Blocked discharge lines and closed isolating valves are just a few of the ways that pressure can build in a positive displacement pump. Today we’re discussing how to select the right relief valve for Viking pumps in GA.

Unlike centrifugal pumps that will cavitate, positive displacement pumps will continue to generate flow and pressure until something gives. Oftentimes it’s the pump and it results in expensive component repair or replacement.

Relief valves can be an important measure when used within positive displacement pumps. These valves avert fluid flow as pressure builds in the discharge line of the pump, preventing failure. There are two types of relief valves, internal and external. Do you know which is right for your system?

Internal Relief Valves in Viking Pumps in GA

Internal relief valves are integral to the pump construction. As pressure builds in the discharge line and on the discharge side of the pump casing, force is distributed on the surface of the poppet valve. When the pressure is greater than the spring tension, which is set manually using the adjusting screw, the spring compresses and allows fluid to pass around the poppet. This channel then becomes the path of least resistance and allows fluid to flow in a continuous loop through the valve body and pump casing.

Due to friction and pressure, the fluid begins to heat up quickly because of its limited flow path. Typically as heat increases, viscosity lowers, and slip increases. Also, depending on the fluid, this rise in temperature could cause vaporization of the liquid or other unwanted results.

External Relief Valves in Viking Pumps in GA

The external relief valve serves a similar purpose as the internal relief valve, diverting fluid flow to lessen the excessive pressure in the discharge line. However, instead of being continuously circulated through the pump, fluid is diverted back into the feed tank or into the suction line upstream of the pump. This allows heat in the liquid to dissipate before returning to the pump, unlike internal relief valves.

Which Is Right for Your Application?

There isn’t a clear-cut answer to this question, as it depends entirely upon the system and media being used. Following are a few things to consider.

Internal Relief should not be intended as your primary safety relief. These valves are ideal for unexpected situations such as blockages in the discharge line. Ideally, flow should not be diverted through an internal relief valve on purpose, and more so used as a redundant safety mechanism.

External Relief valves should be used in systems where the pump will be isolated but will not be shut down. Due to the nature of these valves, described above, they are used as a long-term method of pressure relief.

Having problems deciding which relief valve is right for you? Ask us about it! We are your expert on Viking Pumps in GA and will be happy to help you make the right choice.  In addition to our products, we proudly offer engineering services, repairs, and replacement parts.