Non Slam Check Valve

Check Valve Buyer’s Guide (2021 Update)

Check valves are abundantly found in many industrial applications preventing reverse flow and water hammer. Both phenomena can cause fatal damage to pipework in industries; they can cause rupture or pump damage.

Check valve or one-way valve is a type of valve in which the fluid can flow only in one direction. In case it started to flow in other direction, the valve will close to save the piping and pumps.

Piston Check Valve

Check valves are quite beneficial for the industry; they can save maintenance costs and reduce the chance of damage. The valve efficiently prevents the reverse flow hence protecting essential components and pumps from damage. Water hammer is caused by a sudden pressure rush through a pipeline when the fluid in motion is forced to stop and direction is changed. Water hammer significantly damages the pumps, so check valves come in handy. The valve takes smaller space than traditional valves; moreover, the maintenance cost is meager as there are no moving parts.

Types of Check Valves

Some most common check valves are.

  • Ball Check Valves
  • Double Door Check Valves
  • Lift Check Valves
  • Stop Check Valves
  • Swing Check Valves
  • Tilting Disk Check Valves

Ball Check Valve

As the name prospects, it replaces the disk with a ball to prevent reverse flow. The working is pretty straightforward; under pressure, the ball will lift off the pipe outlet and let the fluid move in one direction, but as the pressure drops, the ball will fall over the outlet and stops the flow.

Double Door Check Valve

Double door or Butterfly check valve features a disc divided into two doors from the center. Both are connected through a hinge that opens up to allow forward water flow and shuts to prevent backward flow. The valve is comparatively small and lightweight, perfect for low-pressure fluid and gas application.

Lift Check Valve

Lift check valve is exceptional; it is the best one for high-pressure usage. In the lift valve, the pressure lifts up the piston or ball to allow the water flow, while as the water starts to flow in the reverse direction, there is no pressure to keep the ball or piston lifted; hence it fell and stops the flow. These valves are also leak-resistant.

Stop Check Valves

Stop check valves are not dependent on gravity or pressure like many other valves. It allows override control regardless of flow direction. We can manually close the stop valve through an external mechanism to control or stop the flow.

Swing Check Valves

The common use of swing check valves is where we have a high percentage of solids in fluid. The disc swings to allow the flow and swings back in its original position to restrict the flow of fluids. It opens and shut slowly and good for pipes where the on/off cycle count is lesser.

Tilting Dish Check Valve

It uses a spring-powered disc to control the flow; it is available in wafer-type and lug-type disks, which tilts up and starts floating under pressure. As the flow reverts, the disc sink and returns to a close position.

Check Valves Applications

We are using check valves in almost every industry because of their benefits and low cost. Below are some industries where check valves are a major component.

Mining

The mining industry is versatile and uses many valves and pumps for many different purposes like dewatering and watering. Check valves are used throughout the mines; many pipes take and bring the water from different locations. A critical application of the check valve is in the dewatering system. The system is responsible for extracting water from the extraction or mining site, and reverse flow will destroy the pumps and bring all the water back to the site. That’s why check valves are necessary.

Moreover, they are used in autoclaving, pump isolation, and discharge.

Food and Beverages

The main problem in the food and beverage industry is contamination by harmful products. Sanitary check valves stop pathogens and other elements from entering the product. Moreover, they are mounted in boiler feed and discharge, cookers, refrigerators, and steam lines to perform their primary task of preventing reverse flow and water hammers. They also guard against the falling pressure by preventing condensate backup when inlet steam is reduced.

Oil and Gas

The oil and gas industry are expensive and has a lot of maintenance costs, so it is better to get a valve with less maintenance cost and incredibly functioning for that check valve. The check valve has a considerably low maintenance cost than other valves, and it precisely performs the task of stopping reverse flow.

Moreover, it has a low-pressure drop which lowers the energy consumption, which also helps in chatter reduction in pipes.

Pharmaceutical

The pharmaceutical industry is pretty much like food and beverage, but it requires extra protection against external elements. The industry also needs effectiveness and efficiency to fight against the reverse flow and water hammer. To overcome the problems of cleanness, water hammer and backflow check valves are used to tackle all three issues systematically.

Power Plant

Power plants are the most important thing for a country; they power the entire country and runs all the industries. They need special care against the reverse flow because a slight flaw can bring the whole system down. That’sThat’s why check valves are so crucial in power plants.

Where to buy Check Valves?

Check valves are a crucial part of every major industry; they play an essential role and save many things from any possible damage. So, it is absolutely essential to buy a high-quality check valve. Numerous manufacturers are selling sub-standard check valves.

So, here are manufacturers whose products are made from high-quality material, and their manufacturing plants are ISO standardized.

DBAOValve (DBV)

DBV is focusing on manufacturing industrial valves since 2001. Over the years, they have brought great innovation and diversity to the check valve market. The well-established DBV is selling valves around the world. They have a great customer base in USA, UK, Japan, Canada, Australia, and European Countries. Moreover, the customer support is excellent.

Warren Valve

Warren valve is providing high-quality products and services for thirty years. They are manufacturing and supplying products and moving quickly to market demands. They have a variety of material options for check valves.

Direct Industry

Direct industry is like amazon for valves. They have all types of industrial products available from many popular manufacturers from around the world. If you are looking to compare products from different brands, then Direct Industry is the spot.

Flowserve

Flow serve is known for its diversity of check valves. They have many different types available in many different materials. Flow serve is rapidly spreading around the world. They are operating in more than 50 countries and growing with the goal of solving fluid motion and control challenges.

For household check valves, you can visit Amazon, Aliexpress, and Grainger.

How to Choose Check Valves?

Check valve is a crucial part of an industry as it is controlling the major flow and prevents disaster due to water hammer. That’s why it is vital to get the right check valve for yourself.

Below are some crucial points that every check valve buyer must consider.

Fluid

Firstly, we have the fluid, typically check valves are designed to handle freshwater and treated water, but they can handle some raw waste. The excess of sewage waste can cause complications. So, you should consider the type of fluid and the percentage of solid matter in the water. In this way, the valve will keep on functioning correctly for a long time.

Flow characteristics of fluid

Considering the flow characteristics of fluid is very important. There are rapidly closing and slowly closing valves. If the water pressure is fast, then the rapid closing of the valve will prevent slamming but causes a surge when the pump will start or shut down. The surge will have effects on the pump because a sudden change in pressure happens.

Construction

Check valves are also used in industries like oil and gas, pharmaceutical companies, food, beverages, and many others. So, a valve has to be able to qualify for all these products. Like in food and pharmaceutical industries, the valve most not cause contamination. Moreover, medicines have certain acids and salts, which can cause a reaction with the valve material hence causing contamination and substandard product. Likewise, in the oil industry, there is a risk of grease buildup so, the valve can work properly.

Lastly, the overall construction is critical because it has to bear strong fluid pressure.

Maintenance

Never forget to consider cost, ease, and speed of maintenance. This is important for the reliability and functioning of the valve. It also covers the type of check valve; for example, we cannot control the flow of fluid in the ball valve, and trying will cause jamming, clogging, and malfunctioning, which will destroy the valve, or you have to pay a lump sum amount to fix it. So, you must choose the right type of check valve for the right function and always consider the maintenance cost, speed and ease.

Non-Slam Characteristics

Non-Slam is the stage when the pump stops, and the flow is reversed. Some fluid may reverse back before the valve gets fully closed. Then the valve is closed, and a change in flow velocity creates kinetic energy, which is turned into the pressure of the fluid.

After closure, you might hear a slamming sound, it is not caused by the closing of the disk or ball, but the pressure spike creates this sound stretching throughout the pipe. We cannot reduce the slamming to zero because of the valve’s geometry; the closure is not fast enough to stop the reverse flow which causes slamming.

Common Causes of Damage in Check Valve

Although check valves are pretty solid and built to last for a long time but some factors can damage the check valve. Here are some common causes of damage in check valves.

Incorrect Installation

Incorrect Installation is the leading cause of check valve damage. By installing it incorrectly, you will create problems in pipelines, pumps, and the valve itself because it might not be able to stop the reverse flow. So, it is better to keep a close eye on the valve and fluid’s flow, positioning, and orientation.

Insufficient Maintenance

Many users neglect the significance of maintenance; it is a definite way to ensure a check valve’s long life and proper operation. One must have them check periodically and look for the signs of wear and tear and check the debris in the pipeline. Ignoring these signs can end up badly.

Reverse Flow

Reverse flow occurs due to improper functioning of the check valve. When the valve allows the reverse flow of water. It is dangerous for the pump because the reverse flow will spin the pump backwards, which will lead to severe pump damage.

Water Hammer

Water hammer is a shock wave that happens when the fluid is forced to stop and change direction. It can cause damage to the pipeline, valve, fittings and joints.

How to Repair a Check Valve?

Repairing a check valve needs a good eye to analyze the problem and good skills to repair it. Major causes of damage are discussed earlier now it’s time to discuss the repairing method.

A check valve cannot be replaced whenever damage occurs. Because the replacement is costly, time-taking typically requires an engineer recommendation and a lot of testing before using the check valve.

So, to avoid all these issues, there is a way to repair the check valve. The repairing needs some special tools but can reduce the money and time investment. There are different ways to repair various damages. Here is a way to fix seat damage in a check valve.

The technician will use his/her experience and special tools. The repairing process is as follows.

  1. Firstly, we will perform liquid penetrant testing. It is the process of testing nondestructive material for flaws like cracks by spreading a liquid dye on pipes.
  2. Then the alloy hardfacing is removed using special machines.
  3. Third step is to perform liquid penetrant testing on the valve surface, and base metal is repaired if needed.
  4. After that, we will install the new hardfacing.
  5. Now it’s time to machine a new seating surface according to OEM specifications.
  6. Liquid penetrant testing is performed again to ensure there is no leakage in the valve.
  7. Lastly, re-assemble the valve and check the seating surface.

Final Verdict

Check Valves are the most crucial part of an industry where the liquid is used. It has great significance in Food & Beverages, Mining and Pharmaceutical industries. Their abundant usage has created many manufacturers, so we have added the list of the best check valves manufacturers. For us, DBV is the best among all; it has high-quality products, years of experience and trusted worldwide.

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