Basics

Regardless of pump type or application, there are basic startup steps. In this article, in addition to covering some general startup procedures, we'll also address some often-overlooked details (common mistakes) that can lead maintenance personnel and equipment to disaster. Note: All pumps mentioned in this article are centrifugal pumps.

I've witnessed some costly startup mistakes that could have been easily avoided if the operator had read and observed a few key points in the equipment's Installation, Operation, and Maintenance Manual (EOMM).

Let's start with a few basic, correct steps, regardless of pump type, model, or application.

1) Carefully review the EOMM and local facility operating procedures/manuals.

2) Every centrifugal pump must be primed, vented, and filled with liquid before startup. Pumps to be started must be properly primed and vented.

3) The pump suction valve must be fully open.

4) The pump discharge valve can be closed, partially open, or fully open, depending on several factors discussed in Part 2 of this article.

5) The bearings of the pump and driver must have the appropriate lubricant at the proper level and/or grease present. For oil-mist or pressurized oil lubrication, verify that the external lubrication system is activated.

6) The packing and/or mechanical seals must be correctly adjusted and/or set.

7) The driver must be precisely aligned with the pump.

8) The entire pump and system installation and layout are complete (valves are in place).

9) The operator is authorized to start the pump (lockout/tagout procedures are performed).

10) Start the pump and then open the outlet valve (to the desired operating position).

11) Observe the relevant instruments—the outlet pressure gauge rises to the correct pressure and the flow meter indicates the correct flow.

So far, it seems simple, but let me offer some advice. Do you initially assume you've purchased a smooth-running pump that generates the appropriate flow and head at its best efficiency point (BEP) and can be started without any problems after simple preparation? If so, you've missed several steps in the startup process described above.

We often find ourselves at a pump, unprepared for initial startup, accompanied by an impatient, inexperienced operations supervisor urging us to "start it." The problem is that there's actually a long list of items that should be completed and/or checked before that dramatic startup moment. Pumps are expensive, and it's easy to squander all that cost, or more, in the single second it takes to hit the start button.

This article will limit its discussion to the "things" required and/or recommended before startup. The more complex the pump and system, the more steps and checks are required. I won't cover more complex installations and procedures, as these operators are typically highly trained and experienced.

The decision and actions regarding the correct pump selection begin long before what we call the critical moment of startup (or what we might call "things to do before or during installation").

Preliminary work that should be completed in advance includes foundation design, grouting, pipe strain relief, ensuring adequate NPSH margins, pipe sizing and system configuration, material selection, system hydrostatic testing, monitoring instrumentation, immersion calculations, and auxiliary system configuration and requirements.

ANSI Pumps

American National Standards Institute (ANSI) pumps are one of the most common pump types in the world. Therefore, this article will explain some important aspects of this type of pump.

ANSI pumps include adjustable impeller clearance settings. There are essentially two contrasting styles, but both must be adjusted to the proper clearance before startup. The mechanical seal also requires adjustment and setting. Important: The seal must be set after the impeller clearance is set; otherwise, the settings/adjustments will be off.

The direction of rotation of ANSI pumps is crucial because if the pump rotates in the wrong direction, the impeller will immediately "expand" (loosen from the shaft) into the pump casing, causing costly damage to the casing, impeller, shaft, bearings, and mechanical seal. Therefore, these pumps are often shipped without a coupling installed. The driver rotation direction must be checked before installing the coupling. Unfortunately, this step is often skipped during field commissioning, a common problem.

Priming

The pump must be primed before startup, a fact often misunderstood or overlooked. Even self-priming pumps must be primed before the first startup. Primed means that all air and non-condensable gases have been expelled from the suction line and pump, and only the (pumped) liquid is present in the system. If the pump is in a submerged system, priming is relatively easy. A submerged system simply means that the liquid source is located above the centerline of the pump impeller. To remove the air and non-condensable gases, they must still be vented to the outside of the system. Most systems will include a vent line with a valve or a removable plug to facilitate venting.

Venting Tips

A running pump cannot be properly vented. The heavier liquid will be expelled, while the lighter air/gas remains within the pump, often trapped in the impeller inlet and/or stuffing box/seal chamber. Improper venting explains the squealing noise heard during startup, which disappears after a minute and before the mechanical seal begins to leak due to dry grinding. Most seal chambers/stuffing boxes should be vented separately before startup. Pumps with throat bushings (restrictive) in the stuffing box present specific venting challenges. Some specialized seal flushing systems and accessories will allow for automatic venting of this design. Don't assume your system has a special design.

Vertical pumps have their own unique venting requirements. Because the stuffing box is at a high point, extra precautions are required in these cases (typically with Plan 13 venting).

Pumps with centerline discharge piping are generally suitable for automatic venting, but not necessarily for stuffing box or seal chamber venting. Axially split pumps or pumps with tangential discharge will require additional means of venting the pump casing (typically by installing a vent pipe at a high point in the pump casing). Regardless of pump type, air still needs somewhere to go, so make sure it has somewhere to go.

The pump suction inlet is not submerged

When the liquid source is below the impeller centerline, the pump must be vented and primed in some other way. There are three main methods:

1) Use a foot valve (check valve) on the suction side of the pump nozzle. Liquid can be added to the suction line, and the foot valve will hold it in the line until the pump is started.

2) Use an external device to create a vacuum on the suction line. This can be done with a vacuum pump, ejector, or auxiliary pump (usually a positive displacement pump).

3) Use a priming tank or priming chamber.

Additional Tips

Foot valves tend to be unreliable and are notorious for failing or sticking in the worst-case scenario in either the fully open or fully closed position. When it fails in a partial position, you might not realize it's not working.

Any air in the suction line still needs to go somewhere (otherwise it's trapped), and the pump won't be able to compress it. You'll need some type of vent line or automatic vent valve. If there's a check valve downstream, the pump won't be able to generate enough pressure to lift and open the check valve.

Self-priming pumps, or those primed from other sources, require lubrication of the mechanical seal during startup and priming. Many self-priming units address this issue by using an oil-filled seal chamber design. Of course, the pump doesn't necessarily have oil in this chamber; you'll need to add it before startup. Other pumps will require an external lubrication source and/or a separate seal flushing system.

A self-priming pump in operating mode won't leak liquid out of the suction line or seal chamber, as these areas are typically under a certain vacuum, but you do realize that air can leak in.

Other Considerations

The following is a summary of other checks and procedures that are often overlooked when starting a pump, in no particular order.

Safety always comes first and should be the primary guideline. Remember, you may be working with a hot, acid-containing, and automatically starting pressurized system. You are also working next to rotating equipment, which will not hesitate to fight back if the correct operating procedures are not followed.

No matter where you start up equipment, there is a 99% chance that the owner has certain mandatory procedures to follow.

However, the most common oversight I see is the operator's manual being discarded, leading to a long list of incorrect operating habits that include things that should be done on-site but are not. Users must understand that no industrial pump is "plug and play."

A simple check is to crank the pump by hand (also known as "cranking"). The pump should turn freely, without binding or friction. Larger pumps may require additional torque due to inertia, and appropriate tools can be used to overcome this torque (be mindful of how and where you use the tool to prevent damage to the pump shaft).

Cranking should be performed after lubrication or startup, but before seal setting. (If the seal flushing system is active or the seal chamber is filled with flushing fluid and adequately vented, cranking can be performed after seal setting. Three to five cranking turns are typically sufficient.) Furthermore, cranking is much easier before coupling assembly.

This means that the system must be locked out and tagged out (e.g., to prevent accidental startup).

Never power a centrifugal pump without first checking the direction of rotation on the unconnected driver! Incorrect cranking is probably the second most common mistake I see.

New systems often have a significant amount of dirt and debris left in the construction lines. Before starting the pump, it is prudent to install a temporary (commissioning) filter in the suction line. The filter must have sufficient flow area to allow adequate flow without significantly affecting the NPSH margin. The filter must have some method of measuring its own differential pressure; otherwise, you won't know when it's clogged.

Pump systems with long, empty discharge lines will experience problems during initial startup. When the pipeline is full of liquid, the pump has little resistance, so it runs at the "end" (i.e., runout) of the curve. You can introduce temporary artificial resistance by partially closing the outlet valve. The risk of water hammer and related damage also increases when the pipeline system is filled.

Before starting the pump, you should know the expected flow rate and pressure (which will be displayed on the instrument). Also, know the expected ampere readings, frequency (if using a variable frequency drive (VFD)), and power readings in advance. If the facility does not have these devices, I like to bring my own strobe tachometer, vibration probe, and infrared digital thermometer (note: permits are usually required, and many facilities do not allow the use of personal equipment).

Before starting the pump, verify that the mechanical seal support system is working. This is especially important in API seal flushing plans 21, 23, 32, 41, 52, 53, 54, and 62.

For pumps using packing in the stuffing box, check to ensure that a flush line is present and, if so, is it connected to a clean liquid source. Also, check that the stuffing box has sufficient pressure (flow). It's best to start the seal flush before opening the pump's inlet and outlet valves. Consult your pump and/or packing supplier to verify the correct packing leakage rate, which will vary with fluid temperature and other physical properties, shaft speed, and size.

If you can't find a reliable answer for your application, use a standard of 10 drops per minute per inch (per 25 mm) of shaft diameter. During the initial break-in period, I typically choose a more generous leakage rate (30 to 55 drops per minute), regardless of diameter.

Adjust the gland in small increments—adjust each gland nut one equal increment at a time—over several adjustments, taking 15 to 30 minutes to complete. Patience is the key to properly adjusting the packing.

Use all your senses when starting the pump and its auxiliary equipment. Check for sparks, smoke, and friction, such as from improperly set bearing isolators or oil deflectors. Listen for the popping of bubbles in the impeller or the squeal of a mechanical seal desperately in need of lubrication. Can you smell it? The packing shouldn't be smoking. Is the equipment loose due to imbalance or cavitation? Can you feel vibration in the floor and/or piping?

Always minimize the time the pump operates in or near the minimum flow area (left side of the curve). Equally important, avoid operating the pump on the extreme right side of the curve (near the runout point).

If you are pumping high-temperature media, avoid thermal shock issues by following a warm-up (pump warm-up) procedure before startup. Large pumps may have minimum and maximum allowable temperature rises and cool-down rates. Many multistage pumps will require a warm-up procedure that also involves slow rotation on the cranking gear for a specified time or a predetermined temperature differential.

During startup, closely monitor the bearing metal temperature (or oil temperature). Do not feel the temperature with your hand, as it is not an accurate method. More importantly, most people will feel the bearing housing is hot at 120°F (49°C). Bearing metal or oil temperatures approaching 175°F to 180°F (80°C to 82°C) are not uncommon. The key parameter to observe is the rate of temperature change. A rapid temperature rise is a red flag. When this occurs, it's recommended to shut down the unit and investigate the root cause. The location where the temperature is measured is also important. A platinum RTD inserted into the bearing or on the bearing outer ring provides a more accurate and timely reading than the bearing oil sump or return line temperature.

During commissioning, the motor may be started frequently. Be aware of the number of starts allowed per unit time for your motor. Generally, larger motors with fewer poles have fewer starts allowed.

Pump Outlet Valve Status

I'm often asked: Should the outlet valve be open or closed when the pump starts? My answer is: It depends, but the pump inlet valve should always be open.

Next, let's look at the impeller. There are many things to consider, but the main question we'll answer today is: What is the impeller geometry? Based on this geometry, we'll determine the range of specific speed (Ns), as shown in Figure 1. To understand the concept of specific speed, let's focus on the directional path of the liquid, specifically how it enters and leaves the impeller. Ns is a predictor of the shape of the head, power, and efficiency curves.

Figure 1: Specific Speed ​​Values ​​for Different Impeller Types

Low Specific Speed

If the liquid enters the impeller parallel to the shaft centerline and leaves it at a 90-degree (perpendicular) angle to the shaft centerline, the impeller is in the low specific speed range.

Medium Specific Speed

If the liquid enters the impeller parallel to the shaft centerline and leaves it at a near 45-degree angle, the impeller is in the medium specific speed range. These are mixed flow or Francis blade impellers.

High Specific Speed

If the liquid enters the impeller parallel to the shaft centerline and leaves it parallel to the shaft centerline, this is a high specific speed impeller. This type of axial flow impeller looks similar to a propeller on a ship or aircraft.

Specific Speed ​​vs. Pump Power Curve Shape

Don't know your impeller's specific speed? Ask the equipment manufacturer.

For low specific speed pumps, as you open the pump outlet valve and increase flow, the required brake horsepower (BHP) increases. As you might intuitively expect, this is a direct relationship. For medium specific speed pumps, the BHP curve and its maximum point shift to the left by a nominal amount. In the past, you might not have noticed this change. Axial flow pumps have high specific speeds, and BHP approaches its maximum at lower flow rates, actually decreasing as flow increases. Perhaps contrary to your expectations? Notice that the slope of the power curve changes when the impeller design changes from low to high specific speed.

Children's toy safety kinetic energy testing is a key testing item for assessing whether the kinetic energy generated by toys in motion (such as projectile, rotation, impact, etc.) may cause mechanical injury to children. It is one of the core indicators of toy safety compliance. Its core purpose is to ensure, through scientific measurement and calculation, that the kinetic energy of a toy's moving parts or movable objects is within a safe range, thereby avoiding risks such as contusions, lacerations, and eye injuries to children caused by excessive kinetic energy.

1. Toy Kinetic Energy Tester Features

The toy kinetic energy tester incorporates multiple features designed to simplify the testing process and enhance accuracy. Notable attributes include a large color display capable of showing charts for up to five tests, providing a comprehensive visual representation of test results. Additionally, the device is equipped with two measurement channels—internal and external sensor channels—to accommodate toys of varying sizes, ensuring the versatility and adaptability of the testing method.

The addition of microcomputer control functionality further enhances the efficiency of the testing process, allowing users to input parameters such as object weight and sensor spacing. These inputs are then used to automatically calculate test speed, kinetic energy, and maximum and average values, eliminating the need for manual calculations and minimizing the likelihood of human error.

Furthermore, the integration of a thermal printer facilitates the generation of experimental results, simplifying documentation and compliance with regulatory standards. This feature not only streamlines the testing procedure but also supports traceability and accountability for toy manufacturers.

2. Toy Kinetic Energy Testing Principle

(1) Projectile Kinetic Energy

Under normal usage conditions, use a method capable of measuring energy with an accuracy of 0.005 joules to measure the toy's kinetic energy. Conduct five measurements. Take the maximum value from the five readings as the kinetic energy. Ensure that the readings are taken in a manner that allows the maximum energy to be determined.

If the toy includes multiple types of projectiles, measure the kinetic energy of each type of projectile.

(2) Kinetic Energy of the Bow and Arrow

For the bow, use arrows specifically designed for that bow, and pull the bowstring with a force not exceeding 30 newtons, to the maximum extent allowed by the arrow, but not exceeding 70 centimeters.

Under normal usage conditions, measure the toy's kinetic energy using a method capable of determining energy with an accuracy of 0.005 joules. Take five measurements. Take the maximum value of the five readings as the kinetic energy. Ensure that the readings are taken in a manner that allows the maximum energy to be determined.

3. Application and compliance with safety standards

The kinetic energy testing machine is designed to comply with internationally recognized safety standards, including ISO 8124-1, GB6675-2, EN-71-1, and ASTM F963.

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In the field of occupational safety and health, the EN ISO 20345:2022/A1:2024 standard serves as the authoritative specification for personal protective equipment—safety footwear. It provides comprehensive guidance for the design, manufacturing, and testing of safety shoes. This article will delve into the key testing requirements outlined in the standard to enhance understanding of its performance specifications for safety footwear.

Key Test Standard Requirements

1. Impact and Compression Testing

The primary function of safety footwear is to protect feet from impact and compression injuries. The EN ISO 20345:2022/A1:2024 standard requires safety footwear to withstand at least 200 joules of impact energy (equivalent to a 20-kilogram object dropped from a height of 1,020 millimeters) and 15 kilonewtons (kN) of compression force (equivalent to a 1.5-ton weight applied to the toe area). These tests evaluate protective performance by simulating real-world workplace risks of heavy object impacts and crushing injuries.

2. Puncture Resistance Testing

Puncture resistance testing is a critical metric for evaluating the ability of safety shoe midsoles to resist penetration by sharp objects. The EN ISO 20345:2022/A1:2024 standard provides detailed specifications for puncture resistance testing, including test methods for both metallic and non-metallic puncture-resistant inserts. For metal anti-penetration plates, the standard requires no more than 3 corrosion points, with an average area not exceeding 2mm². For non-metallic anti-penetration plates, such as composite materials (PL and PS types), the standard requires no perforations after multiple tests and no separation of layers.

3. Slip Resistance Testing

Slip resistance is a critical characteristic of safety footwear, particularly in wet, slippery, or oily work environments. The EN ISO 20345:2022/A1:2024 standard has eliminated the previous SRB and SRC slip resistance ratings, revising the requirements for slip resistance testing. Currently, slip resistance testing is primarily conducted on ceramic tile surfaces using dodecyl sulfate solution. For specific requirements, additional glycerin testing may be performed. Furthermore, testing locations have shifted from the heel and midfoot to the first and third sections of the sole, as well as the heel and forefoot areas, enabling a more comprehensive evaluation of safety footwear's slip resistance performance.

4. Additional Tests

Beyond the fundamental tests outlined above, the EN ISO 20345:2022/A1:2024 standard specifies several supplementary tests to address specific requirements in diverse work environments. These additional tests include electrical conductivity testing, antistatic testing, thermal insulation testing, and waterproof testing. For instance, the waterproof test requires safety footwear to maintain an internal dry environment under specified conditions, preventing moisture penetration that could cause foot injuries.

The EN ISO 20345:2022/A1:2024 standard finds extensive application across all industries. Whether in manufacturing, construction, agriculture, or other sectors requiring safety footwear, adherence to this standard is mandatory for selecting and using safety shoes. These testing standards not only ensure the protective performance of safety footwear but also enhance workers' safety and comfort on the job. Simultaneously, the standard provides manufacturers with clear guidance and requirements, contributing to the standardized development of the entire industry.

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Fully automated fabric stiffness testing serves as a critical method for evaluating a fabric's resistance to bending (stiffness and softness), widely applied in quality control for textiles such as cotton, wool, synthetic fibers, and home textiles. Its core principle involves automatically measuring the bending deformation of fabric samples under specific conditions via mechanical devices to calculate stiffness values. This method offers advantages including high precision, excellent repeatability, and reduced human error. The following details the fully automatic fabric stiffness testing method across six dimensions: testing principle, standard basis, instrument structure, operational procedure, data processing, and precautions.

I. Testing Principle

Fabric stiffness fundamentally represents a fabric's resistance to bending deformation, closely related to fiber type, yarn structure, fabric weave, and finishing processes (such as coating or calendering).

Fully automated testing employs the “cantilever beam method” (the mainstream approach): one end of the fabric specimen is fixed as a “cantilever,” while the other end is allowed to hang freely. The instrument automatically applies a small external force (or relies solely on the sample's own weight) to bend the sample to a specific angle (e.g., 45°, 30°, 15°). The bending length (L) or bending moment (M) at the free end is recorded at this angle. This value is then combined with the sample's mass per unit area (g/m²) to calculate the stiffness index.

Bending Length (L): The horizontal distance the free end extends beyond the fixed end when the specimen is bent to a specified angle, measured in cm.

Stiffness Value (S): Commonly expressed as “bending length × mass per unit area” (unit: mg·cm). Higher values indicate greater fabric stiffness.

II. Reference Standards

Testing standards in different countries/regions specify requirements for specimen dimensions, bending angles, environmental conditions, etc. Common standards include:

GB/T 18318-2009 Textiles—Determination of bending length of fabrics—Cantilever method

ISO 9073-7:1998 Textiles—Test methods for nonwovens—Part 7: Determination of bending length and bending stiffness

AATCC 124-2020 Evaluation of fabric appearance smoothness and stiffness

JIS L1096:2020 Test methods for textiles

III. Test Procedure

Using GB/T 18318-2009 (45° bend angle) as an example:

1. Sample Preparation

Randomly select at least 5 specimens from different areas of the fabric sample. Each specimen should measure 25mm (width) × 150mm (length). Test 5 specimens each in the warp and weft directions to evaluate stiffness differences between warp and weft.

Avoid fabric edges (≥10cm from edge) and defects (e.g., holes, oil stains). Sample edges must be straight (cut with a dedicated cutter to avoid frayed edges).

Environmental Conditioning:

Balance samples in standard temperature and humidity conditions for at least 24 hours (20±2°C, 65±4% RH). Maintain stable conditions throughout testing (prevent airflow interference with specimen bending).

2. Instrument Calibration

Before testing, calibrate the instrument using a standard calibration block (metal strip with known bending length):

Secure the calibration block in the fixture and set the bending angle to 45°;

Initiate the test. If the displayed bending length deviates ≤0.1mm from the calibration block's standard value, the instrument is functioning correctly; otherwise, adjust the optical sensor or mechanical precision.

3. Parameter Setting and Testing

Power on the instrument and its software, select the test standard (e.g., GB/T 18318-2009), and set parameters:

Bending angle: 45°;

Test direction: Warp (or weft);

Sample quantity: 5 pieces (per set);

Movement speed: 5 mm/s (standard recommendation).

Clamping the specimen:

Place one end (lengthwise) of the specimen into the fixture, ensuring it lies flat against the fixture without tension or slack. After clamping, the free end of the specimen should hang naturally downward.

Initiate Test:

The instrument automatically drives the fixture to move, gradually extending the free end of the specimen to initiate bending;

An optical sensor continuously monitors the bending angle. When 45° is reached, the fixture stops moving, and the software automatically records the “Bending Length (L)”;

Repeat the operation to complete testing for all warp and weft specimens.

4. Data Processing and Reporting

Software automatically calculates:

Stiffness value of a single specimen:

S = L×m (where m is the fabric mass per unit area, g/m², pre-measured using an electronic balance with 0.01g precision);

The average (Sˉ), standard deviation (SD), and coefficient of variation (CV% = SD/Sˉ × 100%) for the sample group. CV% must ≤5% (otherwise, resampling is required to eliminate sample non-uniformity effects).

Report Generation:

The report must include: sample name, fabric composition, test standard, temperature/humidity, warp/weft bending length, warp/weft stiffness value, average value, CV%, and be signed for confirmation.

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1. Slip resistance testing of shoes

(1) Ramp Test

Standards: EN ISO 13287, DIN 51130

Procedure:

Test platform: Adjustable-angle ramp (0°–35°),

surface covered with standard test materials (e.g., ceramic tiles, steel plate + glycerin solution to simulate wet and slippery conditions).

The tester wears the shoe sample and gradually increases the incline angle on the platform until slipping occurs.

Critical angle: Record the angle at which the sole begins to slip (the larger the angle, the better the slip resistance).

Grade classification:

DIN 51130: Divided into three grades (A, B, C; Grade A is the highest, suitable for oily industrial environments)

EN ISO 13287: Minimum critical angle ≥12° (dry surface) or ≥8° (wet surface)

(2) Friction coefficient test method (friction tester method)

Standards: ASTM F2913, GB/T 3903.6

Steps:

Contact surface: dry/wet/oily condition;

Pressure: Simulated human foot pressure (e.g., 50 N)

Equipment: Pendulum-type or traction-type friction tester, simulating dynamic/static friction between the shoe sole and the ground

Test Parameters:

Results: Calculate the static coefficient of friction (COF) and dynamic coefficient of friction (generally requiring COF ≥ 0.4).

2. Safety Testing for Footwear

(1) Impact and Compression Testing The primary function of safety footwear is to protect the feet from injuries caused by impact and compression. The EN ISO 20345:2022/A1:2024 standard requires safety shoes to withstand at least 200 joules of impact energy (equivalent to a 20-kilogram object falling from a height of 1,020 millimeters) and 15 kilonewtons (KN) of compression force (equivalent to a 1.5-ton weight applied to the toe area).

Testing methods:

Impact resistance: A specified-weight impact hammer (e.g., 20 kg) is dropped from a specific height (e.g., 30 cm) onto the shoe toe, and the deformation of the shoe toe is measured (must be ≤15 mm), with no sharp edges or cracks inside the shoe toe.

Compression Resistance: Apply vertical pressure (e.g., 15 kN) to the shoe toe using a press, maintain for 1 minute, and inspect for deformation and structural integrity of the shoe toe (no cracking or excessive deformation).

These two tests simulate the risks of heavy object impact and compression injuries in actual work environments to evaluate the protective performance of safety shoes.

(2) Puncture resistance testing Puncture resistance testing is a critical metric for evaluating the ability of the midsole of safety footwear to resist penetration by sharp objects. The EN ISO 20345:2022/A1:2024 standard provides detailed specifications for puncture resistance testing, including testing methods for both metal and non-metal puncture-resistant pads. For metal puncture-resistant pads, the standard requires no more than 3 corrosion points, with an average area not exceeding 2mm²; for non-metal puncture-resistant pads, such as composite materials (PL type and PS type), the standard requires no perforations after multiple tests, and no separation of layers.

Testing method:

Secure the sole sample and use a 3mm-diameter steel nail to vertically pierce it at a specified speed (e.g., 50mm/min), recording the maximum force at the time of penetration (which must be ≥1100N, with some higher standards requiring ≥1500N). Some safety shoes may have steel plates or Kevlar fibers embedded in the sole, and testing must verify their protective effectiveness.

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Hydraulic bursting strength testing is a mechanical property evaluation method used to assess a material's resistance to hydraulic rupture. It is widely applied in quality inspection and performance research for flexible or semi-rigid materials such as films, textiles, leather, rubber, and plastics. The core principle involves applying uniform and progressively increasing hydraulic pressure to the material's surface until rupture occurs, thereby quantifying the material's tolerance limit under dynamic pressure.

I. Understanding the Fabric Bursting Strength Tester

Before conducting bursting strength tests, familiarize yourself with the equipment's key characteristics.

1. Place a specimen of defined area over an elastic diaphragm, secure it with a ring-shaped fixture, and gradually increase pressure beneath the diaphragm via the hydraulic system. This causes the specimen to expand until rupture occurs, determining the bursting strength of woven/knitted fabrics, nonwovens, paper, protective clothing, leather, and cardboard.

2. Specifications and Functions: Understanding the specifications and capabilities of the fabric burst strength tester is essential. This includes its maximum load capacity, test speed, and other relevant parameters.

3. Safety Requirements: Always consult the instruction manual for safety requirements. These may include wearing gloves, safety goggles, and other protective equipment.

4. Testing Standards: Adhere to standards such as ASTM D3786-06, BS 3424-6-B, ISO 13938-1, ISO 3303-B, ERT 80-4.02, and GB/T 7742.1.

II. Technical Specifications:

1. High-definition color touchscreen interface

2. Operates standalone or via computer connection

3. Test platen and collection tray constructed from corrosion-resistant materials

4. Test enclosure features imported high-transmittance POM material with integrated LED illumination for full-spectrum observation of sample testing

5. 32-bit processor; 24-bit high-speed A/D conversion chip

6. Laser displacement sensor measures displacement changes

7. Waste liquid collection system prevents instrument leakage and contamination

8. Overload protection with automatic burst detection system; sensitive and reliable; includes over-range and over-extension protection

9. Built-in thermal printer

III. Test Procedure

1. Power On: Turn on the power supply. Remove the protective cover.

2. Installation: Install the lower fixture: First install the aluminum block, then place the rubber diaphragm (note: the diaphragm has a front and back side; the smooth side faces upward), and finally position the lower pressure plate.

3. Sample Placement: Secure the test sample, ensuring it is properly aligned and tensioned.

4. Parameter Setup: Enter the settings interface to configure test parameters: Set the initial test speed and select the appropriate fixture. Other parameters cannot be modified as they are preset according to standards.

5. Test Initiation: Begin the formal test. Place the sample, clear the data, and click “Test.” Results will display upon completion. You may decide how many tests to perform as needed. Test results will appear after the fabric burst strength test.

IV. Data Analysis and Interpretation

After completing the test, you must analyze and interpret the data—a critical step to ensure the results are usable and accurate. Click the “Check” button to access the results view interface. Click “Print All” to print all results.

Organize the data recorded during testing into a format suitable for analysis. Utilize appropriate tools and methods to analyze the data and draw conclusions about the sample's performance.

By properly familiarizing yourself with the equipment, thoroughly preparing, conducting the test, and analyzing the data, you can ensure an efficient and accurate testing process. Before using any specific equipment, be sure to thoroughly study the operating manual and any relevant training materials. We hope this proves valuable for your testing efforts, ensuring the quality and safety of the products you use.

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About Laboratory Dyeing Machines

Textile manufacturers use laboratory sample dyeing machines to test samples before dyeing large quantities. Textile labs use these machines to research dyeing methods and conduct experiments to achieve the best possible results.

Types of Laboratory Dyeing Machines

Lab-scale dyeing machines are used to simulate the dyeing production process. They can create shades tailored to customer needs and are suitable for large-scale production.

Without a fabric sample dyeing machine, dyeing an entire batch of fabric to the desired shade is risky. Manufacturers can use laboratory dyeing equipment to test their recipes. This allows them to repeat the process until the exact desired shade is achieved. This also helps develop shades at a low cost.

The following are the main types of sample dyeing machines used in the textile and dyeing industries:

Infrared (IR) laboratory dyeing machines

High-temperature laboratory dyeing machines

Oscillating dyeing machines

Laboratory jigger dyeing machines

1. Infrared (IR) Laboratory Dyeing Machine

Infrared laboratory dyeing machines use infrared light to heat the dye bath. They are used to dye a variety of synthetic and natural fabrics. IR dyeing machines use low bath ratios, providing accurate and repeatable results.

The IR dyeing machine is equipped with 24 beakers, allowing for multiple tests to be performed simultaneously. The beakers move in both clockwise and counterclockwise directions, ensuring uniform dyeing.

The IR dyeing machine's beakers are made of stainless steel, allowing for rapid temperature increases and the ability to withstand both standard and high pressures used in the dyeing process.

Infrared heat heats the beaker without any intermediate surface. This reduces electricity costs by up to 50%. A high-precision PT-100 temperature monitoring probe is used to measure temperature.

A digital display shows time, temperature, and program number, simplifying operator control of the machine. The infrared laboratory dyeing machine has a temperature range of 30-140°C and a cooling rate of 0.5-3.5°C/minute.

2. High-Temperature Laboratory Dyeing Machine

High-temperature laboratory dyeing machines can dye synthetic fibers such as nylon and polyester. These machines dye fabrics at a temperature of 140 degrees Celsius, simulating the industrial dyeing process on a small scale.

Using high-temperature dyeing machines facilitates color matching, dye evaluation, quality control, and R&D in synthetic fiber dyeing. They can be used for small-scale fabric dyeing, with each beaker holding up to 300 milliliters of dye.

High-temperature laboratory dyeing machines come with 6 to 24 beakers, depending on the size of the machine. They feature a precise temperature control system, with a digital interface for programming temperature and time.

3. Oscillating Dyeing Machine

An oscillating dyeing machine is used to dye yarn, fiber, fabric, and loose fibers. This machine does not move three-dimensionally. It does not rotate left and right like an infrared dyeing machine.

It uses a reciprocating motion to penetrate the dye solution into the fiber. Oscillating dyeing machines are suitable for dyeing delicate fabrics, such as silk, fine wool, and synthetic microfibers.

The back-and-forth motion reduces wrinkling during dyeing and prevents yarn tangling. It can be used for disperse dyeing at high temperatures. In oscillating dyeing machines, operators use a bath ratio of approximately 1:5 to 1:8 to ensure optimal dye fixation.

The manufacturer's latest oscillating dyeing machines are equipped with a PLC for precise temperature control. You can set the time, temperature, oscillation speed, and direction through the interface.

The unit has a capacity of 24 beakers, each containing 250 ml of dye solution. The shaking distance is maintained at 42 mm, and the operating speed is 0 to 140 rpm.

4. Laboratory Jigger

A laboratory jigger simulates the industrial jigger dyeing process. During jigger dyeing, fabric is passed through a stationary dye bath. The jigger moves with full stretch across a pair of rollers, moving the fabric back and forth in the dye bath.

The jigger is used to dye fabric to ensure wrinkle-free dyeing. The fabric is stretched and then immersed in the dye bath. The jigger consists of a drum and a trough or tray containing the dye bath.

The fabric moves from one drum to another in the dye bath. It then returns from the second drum to the first. This process helps dye the fabric a uniform color.

A laboratory dye jigger precisely controls a variety of factors. It can control the dye bath temperature, the speed of the fabric, and the frequency of dyeing. It also tracks dyeing time and fabric tension. Modern laboratory dye jiggers are equipped with digital controllers and feature automatic dosing and temperature adjustment systems.

This machine is suitable for dyeing at medium and low temperatures up to 98°C under normal pressure. Fabrics can be dyed using reactive, direct, vat, or sulfur dyes.

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The durability of textiles plays a crucial role in ensuring customer satisfaction and product longevity. By subjecting textiles to rigorous testing, this instrument helps manufacturers identify and address potential issues related to pilling and snagging, ultimately enhancing product quality.

1. The Importance of Textile Durability

Textile durability is a key factor directly impacting customer satisfaction and the overall lifespan of textiles. When textiles exhibit signs of pilling or snagging, their aesthetic appeal is significantly diminished and their functionality compromised. Therefore, manufacturers strive to develop textiles with exceptional durability to meet consumer expectations and maintain competitive market advantages.

2. Test Principle:

Place the specimen tube containing the test sample into the pilling test chamber. Activate the instrument, allowing the samples to tumble and rub against each other within the chamber. After the specified number of tumbling cycles, remove the samples for grading.

3. Sample Preparation:

(1) Pretreatment: If pretreatment is required, samples may be washed or dry-cleaned using methods mutually agreed upon by both parties. (Pretreatment is recommended to protect the friction surfaces of the pilling chamber and sample tubes from residual lubricants or finishing agents on the fabric.)

(2) Cut four specimens measuring 125mm × 125mm from the fabric sample. Additionally, cut one identical piece as a reference sample for grading. Fold two specimens lengthwise with the right side facing inward, and fold two specimens widthwise with the right side facing inward. Sew each fold 12mm from the edge using a sewing machine.

(3) Turn the stitched specimens right side out. Trim 6mm ports at both ends of the specimen tube to eliminate stitching distortion. Slip the specimen over the polyurethane specimen tube and secure with PVC tape (ensuring 6mm of polyurethane remains exposed at each end; tape length should not exceed 1.5 times the tube's circumference).

(4) Humidify.

4. Test Procedure:

(1) Clean the pilling chamber.

(2) Place four sample tubes with attached samples into the chamber, securely close the lid, and set the counter to the required rotation count.

(3) Preset rotation count. Agreed rotation count. In the absence of agreement, coarse fabrics undergo 7,200 rotations, while fine fabrics undergo 14,400 rotations.

(4) Start the pilling machine. After testing, remove samples, trim threads, and grade samples.

5. Result Evaluation: Pilling Grade Determination

(1) Evaluation Environment Requirements

Light source: Use standard D65 light source (color temperature 6500K, illuminance 500lx±100lx). The light source angle to the sample surface is 45°, and the observer's line of sight angle to the sample surface is 90° (vertical observation) or 45° (oblique observation, as specified by the standard, typically vertical observation).

Environment: Avoid direct strong light, dust, and colored backgrounds (use neutral gray background, color code N7) to prevent environmental color interference with pilling observation.

(2) Evaluation Method (Example: GB/T 4802.3)

Comparison with reference images: After resting, lay the sample flat on the neutral gray platform and compare it individually with the standard pilling reference images (Grades 1-5), focusing on the quantity, size, and density of pills on the sample surface:

Grade 5: No pills or only extremely slight fuzz (no noticeable spherical protrusions);

Grade 4: Surface exhibits a small number of fine pills (≤5 pills/cm², diameter ≤0.5mm);

Grade 3: Surface exhibits a moderate number of pills (5–10 pills/cm², diameter 0.5–1mm), with no significant large pills;

Grade 2: Numerous pills on surface (pill count >10/cm², some diameter >1mm), with a few large pills;

Grade 1: Surface completely covered with pills, including numerous large pills (diameter >2mm), with some pills adhering together.

Multiple Assessors: At least two trained assessors independently determine the grade. If the difference between their assessments is ≤1 grade, take the average (e.g., one assessor grades 3, another grades 4, resulting in 3.5). If the difference is >1 grade, a third assessor must re-evaluate, and the two consistent results are adopted.

Result Documentation: Record the pilling grade for each specimen. The final pilling test result for the fabric is the average grade of the three specimens (rounded to one decimal place, e.g., 3.3 grade). Include parameters such as the test standard, abrasive type, and test date.

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1. Basic Introduction to Environmental Chambers

An environmental test chamber is a sealed experimental device capable of precisely simulating various natural or extreme environmental conditions (such as temperature, humidity, air pressure, lighting, gas composition, vibration, radiation, etc.). Its core function is to provide controlled and repeatable environmental scenarios for products or materials, enabling the evaluation of their performance, stability, durability, safety, and other critical metrics under different environmental conditions. It is widely used in product development, quality testing, scientific research experiments, and other fields, serving as an “environmental simulation laboratory” for verifying product reliability.

2. Structural Composition of the Environmental Chamber

（1）Control System: Includes control modules for temperature, humidity, lighting, gas concentration, etc., serving as the “brain” of the environmental chamber, responsible for setting, monitoring, and controlling environmental parameters.

（2）Test Chamber: Constructed from high-strength, corrosion-resistant materials, it features excellent sealing and insulation properties, with an adjustable internal space designed to accommodate test samples.

（3）Heating and Cooling System: Enables rapid temperature changes and stable control within the chamber, ensuring the accuracy of the test environment.

（4）Humidity Control System: Utilizes humidification and dehumidification devices to precisely control humidity levels within the chamber, meeting various testing requirements.

（5）Circulation System: Ensures uniform distribution of environmental parameters within the chamber, enhancing the reliability and accuracy of testing.

（6）Monitoring System: Continuously monitors environmental parameters inside the chamber to ensure environmental stability and provide reliable data support for testing.

（7）Alarm System: Issues an alarm signal when environmental parameters exceed the set range, promptly alerting users to ensure safe testing operations.

3. Environmental Chamber Usage Process

When using an environmental chamber for testing, the following process should generally be followed:

（1）Preparation: Inspect all components of the equipment to ensure they are in good condition and that cable connections are secure; clean the interior of the test chamber to ensure no debris affects test results; verify that parameters in the control system are correctly set; place the product to be tested into the environmental simulation chamber.

（2）Set Test Conditions: Based on test requirements, use the control panel to set parameters such as temperature, humidity, lighting, and gas concentration; activate the cooling or heating system to adjust the internal temperature to the desired level; activate the ventilation system to maintain airflow within the chamber.

（3）Begin testing: After setting the test conditions, the environmental testing of the product can commence. Throughout the testing process, closely monitor changes in internal parameters such as temperature and humidity, and promptly adjust relevant parameters in the control system to ensure accurate and reliable test results.

4. Application Cases for Environmental Chambers

(1) When developing an outdoor smartwatch, it is necessary to test its screen display, battery life, and sensor sensitivity under extreme conditions of -30°C (extreme cold) and 60°C (high temperature) in a high/low-temperature test chamber. Additionally, the material of the watch strap must be verified in a humid heat test chamber to ensure it does not crack or mold due to high humidity (90% RH).

(2) Medical devices (such as infusion sets) must undergo sterilization compatibility testing in accordance with ISO 11607 standards. This involves simulating the sterilization process in a high-temperature, high-pressure steam test chamber to verify whether the materials deform or experience performance degradation due to high temperatures.

(3) For special industries (such as aerospace, defense, and polar research), environmental test chambers must simulate extreme environments to verify product reliability under “non-routine conditions.”

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The Martindale Abrasion Test is a test of textile products using the Martindale standard system to determine the abrasion resistance of a fabric. Abrasion resistance refers to a fabric's resistance to repeated friction with other materials. Pilling resistance is a key quality indicator of textile products, directly impacting their durability and performance. The Martindale Abrasion Tester is used to test a fabric's abrasion and pilling resistance.

1. Martindale Test Standards

Because different countries and regions have different standards, we can categorize them into international standards, US standards, European standards, and Chinese standards. Details are as follows:

1.1International Standards

ISO 12947.2—1998 Martindale Test for Fabrics — Part 2: Measurement of Specimen Damage

ISO 12947.3—1998 Martindale Test for Fabrics — Part 3: Measurement of Mass Loss

ISO 12947.4—1998 Martindale Test for Fabrics — Part 4: Measurement of Appearance Change

1.2American Society for Materials (ASTM)

ASTM D4966-2010

1.3EU Standards

EN ISO 12947.2-1998 - Determination of fabric resistance to abrasion and pilling by the Martindale method - Part 2: Measurement of specimen breakage

EN ISO 12947.3-1998 - Determination of fabric resistance to abrasion and pilling by the Martindale method - Part 3: Measurement of mass loss

EN ISO 12947.4-1998 - Determination of fabric resistance to abrasion and pilling by the Martindale method - Part 4: Measurement of appearance change

1.4Chinese Standards

GB/T 21196.2-2007 - Determination of fabric resistance to abrasion and pilling by the Martindale method - Part 2: Measurement of specimen breakage

GB/T 21196.3-2007 - Determination of fabric resistance to abrasion and pilling by the Martindale method - Part 3: Measurement of mass loss

GB/T 21196.4-2007 - Determination of fabric resistance to abrasion and pilling by the Martindale method - Part 4: Determination of appearance change

2. How is the Martindale Wear Test performed?

2.1 Preparation: Check the instrument status and prepare the specimen and sandpaper.

2.2 Specimen Installation: Secure the specimen in the specimen fixture and adjust the contact force between the specimen and the sandpaper.

2.3 Test Parameter Settings: Set the rotational speed, wear load, and other parameters according to the test requirements.

2.4 Test Start: Start the instrument, perform the wear test, and record the specimen wear.

3.Note: The standard friction cloth should be replaced before testing each new sample or after 50,000 cycles. Check the standard friction cloth for contamination or wear and replace if necessary. This method is not suitable for fabrics thicker than 3mm. Samples may be washed or dry-cleaned before testing.

4. Test Results Evaluation Methods

There are three Martindale methods for evaluating fabric abrasion resistance: the specimen breakage method, the mass loss method, and the appearance quality change method. The specimen breakage method is the most commonly used of the three methods, as it offers minimal error, intuitive and clear test results, and facilitates comparison of the abrasion resistance of different fabrics. The mass loss method and the appearance quality change method are more complex to evaluate, but they can reflect the abrasion resistance of a sample at different stages of friction. They are highly practical for manufacturers and research institutions in analyzing fabric usage.

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