Check valves, also known as non‐return, reflux or one‐way valves are automatic valve types that do not require any manual or electrical intervention to open and close.
Check valves are used to allow flow in one direction only and prevent the reversal of flow. They are also used to protect the system and it’s components from water hammer and pressure surges.
Lug type valves are provided with threaded bolting holes in accordance with API 594.

Features

• Lug Type check valve's OD usually do not need machining, and we do tapping on bolt hole.
• While small size lug valve be installed, the piping flange does not have the problem of installation.
• Do not have install problem of pipe flange, especially for small size.
• Even for small size, still has bolt to set each bolthole.
• Bolt hole to be tapped according to client's requests to particularly customized.
• Retail acceptable.
• Beautifully packaged.
• Customized special valve.

Dual Plate Check Valve Installation Guide:

When installing a check valve, it can be used in both indoor and outdoor environments. However, if the medium is corrosive or the surroundings are prone to rust, it is essential to select a valve material combination that matches the conditions to ensure durability and safety. For special operating conditions, it is recommended to consult TVCCL’s technical team for professional advice.
Before installation, all debris, oxidation scale, and solid impurities inside the pipeline should be thoroughly removed to prevent interference with the valve’s operation. During installation, the flow direction of the medium must align with the arrow marked on the valve body. The piping should be aligned at the front and rear centers, with flange interfaces kept parallel and bolts evenly tightened. Special attention should be paid to the distance between the check valve and the pump, which should be six to eight times the valve size to ensure stable system performance.
For routine maintenance, regular inspections should be conducted to check for leakage, abnormal noise, or vibration. In addition, the valve should be periodically examined for signs of corrosion, jamming, or other irregularities. Necessary cleaning, dust removal, and residue treatment should be performed to maintain proper equipment operation and extend its service life.

Specification

• Size: 6" ~ 60" (DN150 - DN1500)
• Pressure Rating For ASME: 125# ~ 2500# Suit For ASME / MSS / API Flange
• Pressure Rating For ISO: PN10 ~ PN40 Suit For ISO Flange
• Pressure Rating For JIS: 5K ~ 20K Suit For JIS Flange
• Material:WCB,CF8,CF8M,ALBC3,A8904A(MOQ)
• Designed in accordance with API 594
• End Connection: Wafer (TC0), Lugged (TC6, TC9), Flanged (TC4)
• (Other flange connection please contact Taiwan Valves Centre Co., Ltd.)
• *Technical information is only for reference. Taiwan Valves Centre Co., Ltd. reserves the right to change without previous notice.

SELECTION GUIDE

1. Clarify Application Requirements and System Conditions
Begin by thoroughly assessing the environment in which the valve will operate. Key considerations include:
• Type of fluid — Is the medium water, oil, gas, slurry, or a corrosive chemical?
• Operating parameters — What are the system’s maximum pressure and temperature?
• Flow behavior — Is there a risk of sudden flow reversal or water hammer?
• Space limitations — Is the piping layout compact or spacious?
These factors help identify the most suitable valve materials and configurations for your system.
2. Select Materials Based on Fluid and Environment
The valve’s body and internal components must withstand corrosion and wear caused by both the fluid and the surrounding conditions. Common material choices include:
• Stainless steel — Excellent for corrosive or sanitary applications.
• Carbon steel or cast iron — Suitable for general-purpose use with non-aggressive media.
• PVC or engineered polymers — Ideal for low-pressure, non-corrosive systems.
Avoid incompatible combinations—such as using brass or mild steel with aggressive chemicals—as this may result in premature failure.
3. Choose the Correct Size and Pressure Rating
Valve sizing should align with the pipe diameter and expected flow rate:
• Proper sizing minimizes pressure drop and prevents turbulence.
• Ensure the valve’s pressure and temperature ratings exceed system requirements to maintain safety and reliability.
4. Evaluate Valve Dynamics and Performance Characteristics
Different wafer check valve designs offer distinct advantages depending on system demands:
• Spring-loaded or dual-plate wafer valves — Provide quick, silent closure to prevent water hammer in high-cycle operations.
• Standard single-plate models — Adequate for slow, steady flow in simpler systems

Seat Material Options for Dual Plate Check Valves

The seat of a dual plate check valve is available in a wide range of materials to meet various media properties, temperature ranges, and pressure conditions. Selecting the right seat material is essential to ensure reliable sealing performance, extended service life, and stable system operation.

Soft Seat Options:
Soft-seated designs provide excellent sealing performance and are typically made from rubber materials such as EPDM, NBR, or FKM (Viton®).

EPDM – Ideal for cooling water, potable water, and general water treatment applications.

NBR – Suitable for oils, air, and other neutral media.

FKM (Viton®) – Offers superior resistance to high temperatures and aggressive chemicals, making it ideal for chemical and petrochemical industries.

Metal Seat Options:
For high-temperature, high-pressure, or abrasive conditions, metal seats are recommended to ensure enhanced durability and wear resistance.
Metal seats can be manufactured from the same material as the valve body or from stainless steels such as SS304, SS316, SS410, or hard alloys like Stellite 6. The allowable leakage rate for metal seats varies depending on valve size.

For any special rubber material requirements, please feel free to contact us.

HEAD LOSS

Head loss refers to the loss of a fluid’s total energy (or pressure) as it flows through pipelines or valves, caused by factors such as friction, turbulence, changes in flow direction, and resistance within the flow path. In a dual-plate check valve, head loss is the pressure drop that occurs when the fluid passes through the valve plates and internal structure.

The smaller the head loss, the lower the resistance the fluid encounters when passing through the valve, the higher the flow efficiency, and the less energy is dissipated. This reduces the system’s pumping energy consumption and improves overall operational efficiency. Conversely, larger head loss indicates greater flow resistance and requires the pump to expend more power to maintain the desired flow rate. Therefore, analyzing head loss data is an important step in valve selection to ensure system efficiency, pressure control, and economic performance.

Dual Plate Wafer Type Check Valve Operation

The dual plate check valve consists of a valve body, valve plates, stem, spring, and seat. It opens automatically under fluid pressure, allowing flow from the inlet to the outlet. When the inlet pressure drops below the outlet pressure, the valve plates close automatically due to the pressure differential and spring force, effectively preventing reverse flow.
This type of check valve is widely used in industries such as seawater desalination, shipbuilding, energy, water treatment, HVAC, and electronics. It serves as a safety device to prevent backflow and water hammer when pumps shut down, protecting the system from pressure surges and reverse rotation.

Advantages of Dual Plate Check Valves

Dual plate check valves offer several advantages that make them ideal for modern piping systems. Their compact and lightweight wafer design allows easy installation between flanges, saving both space and weight. The two spring-loaded plates close rapidly when flow decreases, effectively preventing backflow and minimizing water hammer.
Because of their simple structure and few internal components, dual plate check valves require minimal maintenance and provide reliable automatic operation without external power or manual control. They are available in a variety of materials and configurations, making them suitable for water treatment, HVAC, marine, power generation, and industrial fluid systems.

Functions of Dual Plate Check Valves

The primary function of a dual plate check valve is to prevent backflow and ensure that fluid flows in one direction only. Its two spring-loaded plates respond quickly to changes in flow, closing rapidly when flow reversal occurs to protect pumps, compressors, and other equipment from damage.
In addition to backflow prevention, dual plate check valves help maintain system pressure stability, minimize water hammer through non-slam operation, and improve overall energy efficiency. Their compact wafer-type design allows for easy installation and reliable performance across water treatment, HVAC, marine, power generation, and industrial pipeline systems.

Applications

• Lug type check valve is suitable for a country, which has high-frequency earthquake. Alternatively, the pipe has violently impact and shake often.
• Dual Plate Lug Type Check Valve is suitable for small pipelines and high temperature and high-pressure environment
• Dual Plate Lug Type Check Valve can be applied to various environments such as water, steam, oil, strong acid oxidizing fluid and urea.
• Lug type check valve is fastened directly to the pipe flange by connecting the pipe flange with bolts to the valve body also drilled with threads.
• Dual Plate Lug Type Check Valve is a good solution whenever required compact dimensions and reduced weight.
• Dual Plate Lug Type Check Valve is suitable for use in clean, dirty and seawater applications.
• Lug type check valve is installed above ground in order to reduce congestion.

More Knowledge about TVCCL valve:

TVCCL Dual plate Lug type check valve has a retainer type (TC6) and retainerless type(TC8-2) design. Lug type can make lining rubber inside the body, full rubber lug type check valve (TC7) can satisfied with sea water and high concentration brine…etc. full rubber type could be suitable to use in the media which corrosive easily. Since the length of lug wafer check valve is shorter than the general check valve, make it more suitable for places with installation space restrictions. Lug type check valve’s flange hole is by tapped, so it’s not like flange type, one flange hole needs two nuts, can also save the cost of nuts.

More Knowledge about dual plate check valve:

WCB - This steel has a good welding characteristic, suitable for use in the environment needs seat overlay welding.
Dual plate Lug type check valve enables the one-sided lugging of pipes. Lug type check valve has protruding lugs in the periphery of a body that provides passage to bolt holes that match with those in the flanges. In a lugged connection the valve is fastened directly to the pipe flange by connecting the pipe flange with bolts to the valve body also drilled with threads. Its tight seal and one-piece body prevents operating fluid leakage, allowing for safer more reliable operations. Because it has threaded bolts around the entire area, the lug valve is a safer option. Lug type dual check valve can be used on lines that provide replenishment to auxiliary systems where the pressure may rise above the system pressure. A dual plate Lug type check valve is combined with body, plate, pin and spring. Due to the short closing stroke of the disc and the spring loading, the water hammer is significantly reduced.

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