A duplex webbing sling is a high-strength, flexible lifting sling made from two layers of durable synthetic webbing, commonly used for heavy lifting and secure load handling. These slings are widely preferred in industries such as construction, logistics, and manufacturing due to their lightweight, strong load-bearing capacity, and excellent safety features.

High Strength & Durability
Duplex webbing slings are made from high-quality polyester ,offering excellent load distribution and resistance to wear, UV exposure, and moisture.

Flexible & Lightweight
Unlike chain slings or wire ropes, webbing slings are softer and more flexible, reducing damage to delicate loads while being easier to handle and store.

Increased Safety
With a high safety factor (typically 7:1), duplex webbing slings provide a secure and reliable lifting solution, minimizing the risk of load slippage or failure.

Customizable & Versatile
Available in various lengths, widths, and capacities, these slings can be color-coded for easy identification, ensuring efficient operations on-site.

Where Are Duplex Webbing Slings Used?

· Construction & Infrastructure – Lifting steel beams, precast concrete, and heavy machinery.

· Shipping & Logistics – Securing and lifting cargo safely.

· Manufacturing & Engineering – Handling components with precision and care.

· Automotive & Aerospace – Moving delicate parts without surface damage.

Find the Best Duplex Webbing Sling for Your Needs

At NANJING D.L.T SLING, LTD, we manufacture high-quality duplex webbing slings that meet international safety standards. Our slings are CE and GS certified, ensuring reliability in demanding industrial environments. Contact us today to get expert advice on selecting the right lifting sling for your business!

 

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The ASME (American Society of Mechanical Engineers) standard for webbing slings, specifically ASME B30.9, governs the safe use, maintenance, and inspection of webbing slings, which are used for lifting operations in various industries. This standard provides guidelines to ensure that webbing slings are used safely and effectively, preventing accidents and ensuring the safety of operators and the integrity of loads being lifted.

Webbing slings must be made of materials that are durable and resistant to wear and tear. Common materials used include nylon, polyester, and polypropylene. The ASME standard requires that slings made of synthetic materials be resistant to environmental factors like UV light, abrasion, and chemicals to ensure their longevity and safety.

The ASME standard dictates the minimum size, length, and strength of webbing slings to ensure they can handle the required loads. It also specifies how slings should be designed to minimize damage during use, such as avoiding sharp edges and ensuring the slings have adequate load capacity. The sling's capacity is often indicated on a label that includes the working load limit (WLL).

Regular inspection and maintenance are critical to the safe use of webbing slings. The ASME B30.9 standard provides detailed guidance on the inspection process. It requires operators to examine slings for signs of wear, fraying, and other types of damage before use. Slings should also be cleaned after each use to maintain their integrity.

ASME B30.9 outlines the importance of using the proper lifting techniques to prevent accidents. This includes ensuring the load is balanced and that the sling is correctly positioned. Operators must also be trained on how to safely use webbing slings to ensure the load is secured properly and the sling is not overloaded.

Webbing slings must undergo rigorous testing to ensure they meet the required safety standards. The ASME standard mandates load testing procedures to verify that slings can safely handle the specified weight limits. All webbing slings should be certified, and the certification labels should be visible and legible.

 Webbing slings have a limited lifespan, depending on their usage and the conditions they are exposed to. The ASME B30.9 standard requires that slings be retired after a certain number of uses or when they show signs of damage. Proper disposal procedures are also part of the standard to prevent accidents due to the use of damaged slings.

Graphite heat exchanger

Function: Wall - type heat exchange between two media. There are various structural forms, such as: shell - and - tube graphite heat exchanger, round - block - hole graphite heat exchanger; rectangular - block - hole graphite heat exchanger, etc.

Graphite falling - film absorber

Function: Mass and heat transfer. Carry out falling - film absorption on soluble gases and remove the absorption heat at the same time. For example: shell - and - tube graphite falling - film absorber; round - block - hole absorber.

Combustion synthesis device

Function: Combustion or synthesis of combustible substances. It can also complete synthesis, cooling and absorption in one device at the same time; for example: water - jacketed hydrogen chloride synthesis furnace, three - in - one hydrochloric acid synthesis furnace, etc.

 

Graphite sulfuric acid dilution cooler

Function: Dilute (cool) sulfuric acid and other media, and can remove the dilution heat (cooling) in one device at the same time.

 

Graphite tower - type equipment

Function: Mass - transfer equipment for gas - liquid phase or liquid - liquid phase. Including plate towers and packed towers, etc.

 

Graphite mechanical equipment

Function: Equipped with a power device, used for mixing, reacting, concentrating, evaporating, etc. of materials.

 

Graphite - lined equipment

Function: Equipment with graphite rotors or plates as anti - corrosion linings.

Graphite pipelines and pipe fittings

Function: Used for transporting media and connecting equipment.

 

Graphite sealing materials

Function: Used for end - face sealing, packing sealing, flange sealing.

Graphite protective anode in cathodic protection system

Function: Used as an external - current protective anode in the cathodic protection system.

Fluoroplastic magnetic pumps replace dynamic seals with static seals, keeping the flow components completely sealed. This solves the problems of leakage, spouting and dripping that cannot be avoided by mechanical seals in other pumps. The magnetic pump selects engineering plastics, corundum ceramics and stainless steel with corrosion resistance and high strength as manufacturing materials. Therefore, it has good corrosion resistance and can prevent the conveyed medium from being contaminated. The magnetic pump has a compact structure, beautiful appearance, small size, low noise, reliable operation and convenient maintenance.

If no protective measures are taken for the flange of the fluoroplastic magnetic pump and it is exposed to a corrosive environment or contaminated industrial atmosphere, the corrosion rate will be very fast. In addition, due to the complex geometric shape of the flange connection, gap corrosion between the two flange faces and galvanic corrosion between different metals are prone to occur, which will seriously damage the integrity of the pipeline system. So how can flange connections prevent corrosion?

1. Mechanical solutions: mainly by using protective covers and clamps to seal the gaps between flanges and flange faces, usually made of stainless steel or plastic with rubber sealing strips. This protection method is less flexible and requires storage of covers or clamps that match the size of various flanges completely.
2. Thermoplastic solutions: Thermoplastics are essentially a kind of waxy fusible polymer heated at high temperature, which is sprayed onto the surface of the base material through professional thermoplastic equipment. The advantage of this protection method is that it can be remelted and reused, saving costs. However, this method still requires hot work, professional equipment and construction services. Although it can be reused, it is not easy to open and seal during maintenance.
3. Tape or semi-solid anti-corrosion tape solutions: Rolled tapes (such as petrolatum tapes, wax or elastic polymer bandages) are protected by winding on the surface of the base material. Due to the good water resistance of semi-solid polymers, this protection method can provide reliable anti-corrosion protection.
4. Maintenance paint solutions: Maintenance paint is a hard film that can be directly bonded to the base material, generally epoxy or polyurethane coatings. There are many corners and edges on the flange. Due to the edge thinning effect, conventional paint systems are difficult to effectively cover the edges. Although thickening the coating will solve the edge protection problem, it will also seal the fasteners and make them unable to be disassembled during subsequent maintenance. In addition, operating the bolt will damage the coating and must be repainted after maintenance.
5. Polymer sealing bag solutions: The sealing bag can completely wrap the flange. Its composition consists of low-permeability polymers, corrosion inhibitor vapors and desiccants. It is easy to install, but the two ends of the bag are only sealed with tape instead of using a durable and effective mechanical bond. There is a large area of steam space inside the bag, which is easy to gather a lot of water, and the corrosion inhibitor will also be consumed over time.

 

The GH series floating-head tubular graphite heat exchanger, simply known as the floating-head tubular heat exchanger and also referred to as the graphite heat exchanger, is one of the products of Shengshi Datang, a graphite heat exchanger manufacturer with more than twenty years of production experience. Due to the special design of the equipment head and the use of graphite tubulars as the heat exchange medium for the internal tube sheets, it is named the GH series floating-head tubular graphite heat exchanger.

 

This article introduces three major design structures of the GH series floating-head tubular graphite heat exchanger of Shengshi Datang:

 

First, the design of this equipment takes into account the reduction of fluid resistance and is divided into two types: one is an ordinary heat exchanger, and the other is a condenser with a gas-liquid separator for an ordinary heat exchanger.

 

Second, this product is applied in technological transformation projects. The values are calculated based on the middle diameter of φ32/22 graphite tubes. For detailed design parameters (design pressure, design temperature, heat exchange area, etc.), please contact the technicians of Shengshi Datang, the graphite heat exchanger manufacturer.

 

Third, the floating-head tubular heat exchanger is widely used. This equipment is mainly used as a cooler, heater, condenser, and heater, etc. The following picture shows the structure diagram of the GH series floating-head tubular graphite heat exchanger of Shengshi Datang.

If you want to know more about where to find graphite heat exchangers, graphite condensers, graphite falling-film absorbers, graphite heaters and other graphite corrosion-resistant equipment, feel free to follow Anhui Shengshi Datang Chemical Equipment Group Co,Ltd.

 

Knowledge of pumps

 

Magnetic drive pumps and centrifugal pumps are two common types of pumping equipment. They are different in structure, working principle, characteristics of use, and scope of application.

 

Structural difference

Centrifugal pump

Centrifugal pump usually consists of a motor, pump body, impeller, seal and other components, the motor drives the impeller to rotate at high speed, and the liquid is transported by centrifugal force.

Magnetic pump

The magnetic pump cancels the mechanical seal, uses the magnetic vortex generated by the internal and external magnetic to drive the impeller, and the internal and external magnetic rotor transmits power through the magnetic coupler to achieve no leakage transport of the medium.

 

Working principle

Centrifugal pump

Centrifugal pumps use impeller rotation to generate centrifugal force, suction liquid from the inlet and discharge from the outlet.

Magnetic pump

The magnetic pump transmits power through the magnetic coupler, and the magnetic interaction between the inner magnetic cylinder and the outer magnetic cylinder makes the impeller rotate synchronously, and the medium is in a closed state throughout the whole process to prevent potential leakage.

 

Usage characteristics

Centrifugal pump

Centrifugal pumps are simple and compact, suitable for high-flow transportation, and can be manufactured with corrosion-resistant materials, but there may be mechanical seal leakage problems and relatively low efficiency.

Centrifugal pumps are widely used in the transport of clean water, pure water and other liquids, as well as some specially designed centrifugal pumps can transport suspension and bulk solid suspension.

Magnetic pump

The magnetic pump has the advantages of zero leakage, no independent lubrication and cooling water, static seal of the pump shaft, overload protection, etc., but the price is relatively high, and it is not suitable for transporting media containing particles.

The magnetic pump is suitable for transporting flammable, explosive, volatile, toxic and valuable liquids, especially for industries with more stringent safety standards.

 

 

The design of fluoroplastic magnetic pumps not only has the advantages of ordinary magnetic pumps such as compact structure, attractive appearance, small size, low noise, and reliable operation, but also all of their flow components are made of "Plastic King" (fluoroplastic), which currently has the best corrosion resistance performance. The isolation sleeve is made of materials with high mechanical properties, eliminating the magnetic eddy current phenomenon existing in ordinary magnetic pumps. Therefore, fluoroplastic magnetic pumps can convey corrosive media such as acids, alkalis, oxidants, etc. of any concentration (strength) without damage.

Fluoroplastic magnetic pumps adopt a rear-pull structure, which allows a single person to easily perform internal inspections and part replacements without disassembling the pipeline, greatly facilitating daily maintenance and repair work. Proper maintenance is more conducive to extending the service life of the magnetic pump.

 

Details of Reasons Why Fluoroplastic Magnetic Pumps Are Prone to Damage:

1. Pumping Liquids with High Specific Gravity

a. When the specific gravity is too high, the torque of the fluoroplastic magnetic pump is poor, and the power transmission of the ordinary external magnetic coupling is limited.

Solution: Select a suitable fluoroplastic centrifugal pump, which has high efficiency and cost performance, and is equipped with a water-cooled mechanical seal. If you still want to use a fluoroplastic magnetic pump, you need to configure a high-strength magnetic group rotor assembly at a higher price. Or reduce the impeller diameter to reduce the torque.

b. The reason for the pump shaft breakage of the fluoroplastic magnetic pump: when the outlet head is high and the medium specific gravity is large, there is no check valve in the outlet pipeline. When the machine shuts down, the liquid falls at a high speed, and the water hammer effect damages the impeller and the pump shaft, causing the impeller to be displaced. When restarting, the impeller rubs at high speed and melts and adheres.

Solution: Install a check valve more than 1 m above the outlet pipeline to prevent the water hammer effect from damaging the impeller and the pump shaft.

c. When pumping liquids with a relatively large specific gravity and high speed, the torque is insufficient, and the pump shaft of the fluoroplastic magnetic pump breaks.

Solution: For pumps above 15 kW, a control cabinet can be matched. Before starting, start softly. Normally, it starts from 2900 rpm in 5 seconds and is controlled to reach 2900 rpm in 15 seconds, gradually increasing the power to prevent the pressure generated by high-speed rotation from twisting off the fluoroplastic magnetic pump shaft. Or reduce the impeller diameter to reduce the torque.

2. Idling of Fluoroplastic Magnetic Pumps

When the fluoroplastic magnetic pump is started with the motor running and there is no medium liquid to cool the internal environment, it generates high temperature during long-term rotation, melting the fluoroplastic lining, and the impeller is damaged and adhered.

 

Fluoroplastic magnetic pumps are compact in structure, attractive in appearance, small in size, low in noise, reliable in operation, and convenient for use and maintenance. The products are widely used in chemical, acid-making, alkali-making, smelting, rare earth, dyeing, medicine, papermaking, electroplating, pickling, radio, scientific research institutions, national defense industry and other units to pump acids, alkali solutions, oils, rare and precious liquids, toxic liquids, volatile liquids, especially for the pumping of liquids that are prone to leakage, flammable, and explosive. It is more ideal to select a matching explosion-proof motor. Applicable temperature: -20°C to 120°C.

Kenmold is one of the leading offshore mold builders for manufacturers in the United States. What separates us from other offshore suppliers?

 

 

 

 

At Kenmold, we pride ourselves with the transparency we provide our customers regarding their projects. When dealing with other offshore mold builders, you may feel that your project is out of your control. Not at Kenmold. We provide you with weekly reports on your project and our US-based customer support team located in Bowling Green, KY is available anytime you need them to answer any questions you may have regarding your project.

 

 

Bonve rotary lobe pumps are widely used in industries for their efficiency and reliability in handling viscous fluids.

However, like any mechanical equipment, they may encounter operational issues over time.

This blog outlines common problems, their root causes, and practical solutions to keep your pump running smoothly.

1.  Pump Fails to Start or Rotate
Possible Causes:
1). Power supply issues: Tripped circuit breakers, blown fuses, or disconnected wiring.
2). Motor failure: Burnt motor windings or damaged bearings.
3). Mechanical jams: Rotor blockage due to debris or solidified media.

Solutions:
1). Check electrical connections, reset breakers, and replace fuses.
2). Test the motor for faults and replace damaged components.
3). Clean the rotor chamber and ensure no foreign particles are obstructing movement.

2.  Low Flow Rate or Pressure
Possible Causes:

1). Incorrect rotation direction: Motor wiring reversed, causing reverse flow.

2). Clogged pipelines or valves: Blockages in inlet/outlet pipes or partially closed valves.

3). Worn rotors or chambers: Erosion from abrasive media reduces pumping efficiency.

4). High fluid viscosity: Exceeds the pump’s design capacity, slowing flow.

Solutions:
1). Verify motor rotation aligns with directional markings and adjust wiring if needed.

2). Clean filters, open valves fully, and clear pipeline obstructions.

3). Replace worn rotors or liners and select a pump suited for higher viscosities.

3.  Excessive Noise or Vibration
Possible Causes:
1). Bearing wear: Lack of lubrication or contamination causes friction.
2). Misaligned couplings: Poor alignment between the pump and motor shafts.
3). Cavitation: Air ingress or low inlet pressure creates bubbles in the fluid.

Solutions:
1). Lubricate or replace bearings regularly.
2). Re-align couplings and ensure the pump-motor assembly is level.
3). Check for air leaks in suction lines and prime the pump properly.

4.  Leakage at Seals or Joints
Possible Causes:
1). Worn mechanical seals: Aging or abrasive media damages seal surfaces.
2). Loose fittings: Improperly tightened bolts or degraded O-rings.

Solutions:
1). Replace mechanical seals or O-rings and ensure correct installation.
2). Tighten connections and inspect pipelines for cracks.

5.  Overheating or High Motor Load
Possible Causes:
1). Excessive discharge pressure: Overloading due to system resistance.
2). High fluid temperature: Inadequate cooling or ambient heat.
3). Internal friction: Rotor scraping against the chamber.

Solutions:
1). Reduce backpressure by enlarging discharge pipes or removing restrictions.
2). Install cooling systems or switch to heat-resistant materials.
3). Adjust rotor clearance or replace damaged components.

Preventive Maintenance Tips
To minimize failures, adopt these practices:
Regular inspections: Check seals, bearings, and alignment monthly.
Lubrication: Use high-quality grease for bearings and gears.

Proper shutdown: Drain and clean the pump after use to prevent media hardening.
Correct installation: Ensure inlet/outlet orientations match design specifications.

Conclusion

Understanding these common issues and their fixes can significantly extend the lifespan of your cam rotor pump.

Always prioritize preventive maintenance and consult professional technicians for complex repairs.

For specialized support, partner with trusted manufacturers to ensure optimal performance.

For more detailed guides, explore our technical resources or contact our team!