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Benefits of Vacuum Breaker Check Valves

What It Is

Vacuum breaker check valves relieve unwanted low-pressure conditions within closed systems. They are installed directly into the system and allow air to enter the system when internal pressure drops below atmospheric pressure. When closed tanks are drained of liquid or during a phase change — when water transitions from steam to condensate, for example — the pressure within a pipeline or vessel can fall below atmospheric pressure. This results in a dangerous condition where pressure outside the vessel is greater than pressure inside. A vacuum breaker allows air to enter the system to equalize the pressure and ensure safe operational conditions. Without this safety component, there is the potential for damage, collapse, or rapid implosion. A vacuum breaker can also prevent a siphon and backflow contamination.

How It Works

Benefits of Vacuum Breaker Check Valves

A vacuum breaker check valve is a device that allows for the flow of air in one direction, but closes to prevent flow in the opposite direction. When the system is at normal pressure, the greater the pressure inside the system compared to the pressure of the external environment keeps the door of the vacuum breaker shut. A spring assists in keeping the valve closed. When pressure in the system drops below that of the external environment, the valve opens to allow air into the system, equalizing pressure inside and out. The valve system is selected to control at what pressure difference the valve first opens. The valve spring is designed to allow the valve to open at a set pressure difference (called the “cracking pressure). Valve size selection is important for allowing sufficient airflow into the system, depending on how quickly liquid is being evacuated that needs to be replaced by air or how rapidly pressure is dropping because phase change is occurring. Vessel collapse is prevented.

Once the pressure difference is lowered to an acceptable level, the valve closes, forming a tight seal to prevent outward flow. No system fluid can escape into the atmosphere.


In addition to preventing damage and even collapse in systems that experience vacuum conditions, vacuum breaker check valves can be used to prevent siphoning of tank discharge lines with terminations below the tank fluid level. These devices can also be used to prevent backflow of liquid into system lines when a discharge pipe terminates under the surface of the liquid in another container. The latter example is commonly seen on outdoor faucets.

Benefits of Vacuum Breaker Check Valves

Vacuum breaker check valves are simple mechanisms that respond quickly to small pressure differences. Their quick action can minimize the risk of vessel or piping collapse. These valves can also keep a fluid system safe by preventing siphon-powered backflow and contamination.

Vacuum Breaker Check Valves From DFT® Inc

DFT® Inc specializes in providing high-quality check valves and control valves to our customers. We build each of our DFT® NPT-threaded Vacuum Breakers (BSSV) from stainless steel, with a lapped disc and seat that provides a reliable seal. These valves are available in sizes ranging from one inch to four inches in diameter. Other sizes, materials, and mating configurations are also available. Contact us today to learn more about our products or request a quote to get started.

Vacuum Breakers in the Textile Industry

textilesTextiles is a global industry comprised of a wide array of manufacturing and processing stages. Starting as natural and synthetic fibers and threads, materials like cotton and yarn go through spinning and dyeing processes before their export as finished cloth goods. The textiles industry continues to grow, using diverse materials with different colors, properties, and specialized applications.

To facilitate this production, manufacturers increasingly turn to specialized machinery that can meet the demands of consumer, military, and industrial standards. Regardless of the machine or textile itself, however, most of these machines require the same underlying equipment: boiler and compressor systems that use vacuum breakers, chemical lines, and condensate lines.

Applications of Vacuum Breakers in the Textile Industry

A vacuum breaker is a specialized valve that protects pressure vessels, as well as pressurized tanks and piping. The textile industry has uses for vacuum breaker check valves and control valves throughout numerous stages of production. Some of the most common applications of these components include:

  • Regulating heat from steam boilers. This heat has uses in fabric dyeing and drying processes.
  • Creating pressure relief points. Valves allow pressure release for air compressor systems that need to run continually without downtime.
  • Controlling the flow rate and volume of fluids. Accomplished along with the help of metering pumps, valves ensure a steady, sufficient flow of liquids such as chemicals and water. They also discharge substances from boilers, compressors, and pumps.

Vacuum Breaker Benefits in the Textile Industry

vacuum breaker valveVacuum breakers provide effective protection against the collapse of pressure vessels by preventing back-up material from entering the systems. For example, vacuum breakers can prevent condensate from backing up into previous parts of a system when it goes down or there’s decreased inlet steam.

Vacuum breakers help create safer systems, with some of the tasks they can handle including:

  • Stopping pipe collapses if the transient pressure drops 
  • Breaking siphons
  • Stopping water hammer by allowing more air into the downstream portion of the piping after the check valve
  • Preventing the formation of dangerous vacuums

Why You Need Vacuum Breakers

Vacuum breakers can protect your pressurized system from impairment in the event of pressure loss or over pressurized systems. They prevent dry can, slasher collapse, and pressure vessel collapse. In steam heated drying cylinders, which often dry ink on printed fabric, internal steam can condense into water during system downtime, creating a vacuum in the cylinder. Guarding against this, vacuum breakers can help keep your textile systems running efficiently and on time.

Vacuum breakers provide a tight shutoff to stop steam from leakage when a system is in use and then allow steam to escape during cooling cycles. Without vacuum breakers, the pressure shifts between highly pressurized “on” periods and depressurizing “off” periods can jeopardize the integrity of your equipment and lead to costly damage and downtime.

Vacuum Breakers From DFT® Inc.

The right vacuum breakers have strong seals to prevent leakage but are responsive enough to allow for the release of steam as needed to keep your textile operations running smoothly across each stage of production. Whether your facility specializes in synthetic fabrics, organic and natural fabrics, or dyed and treated textiles, the right equipment makes all the difference in completing orders on schedule and creating consistent products.

At DFT®, we serve our customers with a wide range of check valves and control valves. Our durable stainless steel DFT® Vacuum Breakers (model BSSV) are available in 1-inch to 4-inch diameters with a lapped disc and seat for tight shutoff. Contact us today or download our flyer to learn more about our Vacuum Breakers. You can also request a quote if you are ready to start your order.

Download Vacuum Breaker Flyer

Reverse Osmosis and Purified Water

Clean water is important for industrial processes, but the water a facility receives may not be clean enough. Using a reverse osmosis (RO) purification system can provide the level of purity companies need for product specifications and quality standards. Reverse osmosis water purification is a common technique for removing impurities from water for use in processing everything from pharmaceuticals to food and beverages. Systems using reverse osmosis rely on durable check valves to dependably manage reverse flow and water hammer to purify contaminated water.

Why Check Valves for the Reverse Osmosis Industry?

reverse osmosis system at a plantReverse osmosis processes use pressure and a semipermeable membrane to purify water. In the first stage, unpurified water, or feedwater, enters a system. The system applies pressure so that the feedwater flows from the intake point to downstream operations, passing through a membrane. At this stage, the membrane collects any impurities and allows only purified water through, which is also called permeate water. Valves manage that flow to ensure a steady stream of water that will not overwhelm the system. 

Different check valves provide different benefits, functionalities, and levels of control at various stages. For example, a check valve located after water exits the membrane housing stops backflow and ensures that permeate water continues out the outlet port. Check valves are also required components for reverse osmosis systems that have automatic shut-off valves and pressurized tanks. When a tank is full, it creates enough back-pressure that it could send water surging backward through the system, causing breakage or recontamination. A spring-assisted valve can stop purified water from exiting back through the membrane. Flow only begins again after the back-pressure is below the feed pressure.

While check valves can protect the reverse osmosis setup, they do experience harsh conditions. Corrosive seawater and chemical contaminants can degrade these valves. Over time, dissolved salts (ions), chloride, and other chemicals will break down the seal and housing, which can lead to contaminated water. However, facilities can reduce the risk of deterioration by choosing the right seals and housings for the expected contaminants and environmental conditions. Nickel-aluminum-bronze and duplex stainless steel valves, for example, can withstand constant exposure to seawater. These materials are commonly used in check valves for reverse osmosis/desalination plants throughout Saudi Arabia, Israel, and the coast of California.

Reverse Osmosis Applications and Industries

Water purity is especially essential for the production of consumable goods, and reverse osmosis systems used along with other water treatment systems meet this challenge. Two of the most common industries with applications for reverse osmosis valves are:

  • Food and beverage. Reverse osmosis can purify water to guarantee safety, consistency, quality, and controllable tastes and odors in the final products.
  • Pharmaceuticals. Pharmaceutical manufacturers cannot create safe products without pure water. Even trace amounts of bacteria, organic material, chemicals, or minerals can jeopardize a product. In fact, some of the strictest water purity mandates call for water that has 10,000 times lower impurity levels than safely rated drinking water.

No matter the industry or water source, DFT® Inc. manufactures and distributes check valves that can keep reverse osmosis equipment running smoothly. Four of our highly recommended RO valves are:

  • GLC® NAB (Nickel-Aluminum-Bronze) Silent Check Valves
  • GLC® (Duplex Stainless Steel) Silent Check Valves
  • Excalibur® NAB (Nickel-Aluminum-Bronze) Silent Check Valves
  • Excalibur® (Duplex Stainless Steel) Silent Check Valves

GLC NAB check valveExcalibur NAB check valve

These check valves have a spring-assisted and non-slam design with applications in pressurized systems for preventing water hammer and in systems with exposure to extremely harsh conditions. With their use in brine, brackish water, and more, check valves are rated to withstand corrosion and deter marine life. They also feature a nozzle style for easy operation and require little maintenance.

Choose Reverse Osmosis Check Valves From DFT®

Reverse osmosis systems can purify water to make it safe for drinking, industrial processes, and pharmaceutical and food production. In those systems, check valves allow for safe and efficient water processing. For over 75 years, DFT® has innovated to provide its customers with in-line check valves and severe service control valves to fit their specific needs. Contact us today to learn more about our capabilities, or request a quote to start your order.

Check Valves in the Natural Gas Industry: Explore Our eBook

Natural gas demand rises in tandem with economic growth. For example, in the Utica and Marcellus Shale areas, the need for metering facilities and gas compression stations has expanded rapidly in recent years. Forecasts suggest that this ongoing infrastructure expansion should continue for the foreseeable future.

A Large Natural Gas Company in West Virginia was experiencing issues with its piston check valves. They were installed at its compressor station located near the natural gas underground storage.

Six of the 6” 900# WCB/SS DFT® model PDC® Check Valves were the right solution to replace the piston check valves originally installed for this application.

Learn About Our PDC Valves: Download Our eBook

DFT® Model PDC® Features:

  • PDC check valve2” to 26” line size
  • ASME class 150 to 1500
  • RF & RTJ flanged ends
  • ASME B16.10 face-to- face dimensions
  • Standard Body Materials:
    • A216 WCB carbon steel
    • A351 CF8M stainless steel
    • A352 LCC low-carbon
  • Stainless steel trim
  • Center-guided/dual-guided stem
  • Spring assisted silent closing, non-slam
  • Tight shutoff – lapped disc & seat
  • Horizontal or vertical installation
  • Protected spring
  • Axial Flow
  • Nozzle style

Access our eBook to Learn More about the Role of Natural Gas in Today’s World

Proper check valves reduce the likelihood of malfunctions and potentially catastrophic side effects in your natural gas system. Our new eBook, Check Valves in the Natural Gas Industry, explores:

  • Which Check Valves Are Suitable for Natural Gas Applications?
  • How long Do DFT® Check Valves Last?
  • Construction of the PDC® and GLC® Check Valves

Download Your Free Copy Now!

Additional Resources

You can also download our free webinar, Engineered Check Valve Solutions For Natural Gas Applications to learn more about the important role of check valves and how to resolve flow issues and avoid failures.

The experts at DFT® can help you select the best check valves for your needs. If at any time you have additional questions, please contact us or request a quote.

Watch Our New Company Video: DFT® World-Class Manufacturer of Check Valves and Control Valves

For more than 75 years, DFT® has been in the business of manufacturing check valves and control valves in the United States. What sets DFT® apart from our competitors is that we are an engineered valve company. Our objectives are to solve check and control valve problems and prevent issues like water hammer and check valve failure.

Using the latest design and manufacturing technology, DFT® makes reliable products in accordance with our ISO 9001:2015 quality management system.

Our new company video, DFT® World-Class Manufacturer of Check Valves and Control Valves, provides details on our full line of check valves and control valves. Constructed from carbon steel, stainless steel, exotic alloys, and other materials, our valves can meet customer requirements regardless of their industry, size, pressure, or piping configuration. Additionally, our top-of-the-line severe service control valves feature a straight-thru design that is cavitation resistant.

We’re proud to manufacture world-class severe service control valves and silent check valves, including spring-assisted, in-line, nozzle style, and axial flow varieties. To learn more about DFT®, contact our team of experts or request a quote today.