Vacuum priming systems are engineered vacuum systems designed for the specific application of removing air from the negative pressure side of the piping so that flow can ensue and be maintained.
Vacuum priming systems are used in several applications, but predominately to prime centrifugal pumps when installed without a flooded suction. The vacuum priming system floods the suction piping so that the pump can be started. Automatic systems maintain the prime between pump operation so that any pump connected to the vacuum priming system can be started without delay. Siphons are another huge application for vacuum priming systems. Whether siphoning from a river, reservoir, pond or ocean a siphon priming system is designed to prime the siphon to initiate flow, and maintain the siphon so flow is not diminished or interrupted with loss of prime.
The application is critical to the design of a priming system. Many factors can affect system performance and equipment reliability. Designs that are well suited to maintaining a prime to multiple centrifugal pumps are not necessarily well suited to priming a reservoir siphon.
Siphons are particularly well suited for priming systems. Large capacity siphons need to have their prime maintained once flow has been initiated. The priming system serves two functions, prime the siphon to initiate the flow and to maintain the siphon by continuously removing air that outgasses or leaks into the system.
No, a properly sized automatic priming system can prime and keep primed several pumps together, allowing start-up of any pump when needed without delay.
Condensation buildup in the priming system’s vacuum tank is normal and typically varies seasonally. Regular draining keeps condensation buildup in check. LYNN offers automatic vacuum tank drains that can be furnished with our systems or easily added to existing systems.
Complete system flooding occurs with a failure of the priming valve seat or improper sizing of the priming valve. Properly designed priming systems provide complete protection of the vital system components in the event of flooding.
Priming valves are basically an air release valve. They are employed in conjunction with a priming system for the removal of air in the negative pressure sections of piping to either prime a pump or siphon. A key feature of the valves is to automatically close on a prime condition, preventing the carryover of water back into the priming system’s vacuum pump.
I was sold a liquid separator/water trap as a part of my new priming system to protect the system against flooding. However, I regularly loose prime to my pumps and my system still floods.
Liquid separators, also commonly referred to as water traps are frequently employed improperly to protect the vacuum pumps from flooding in a poorly designed priming system. With their typically small capacity they rapidly accumulate normal condensation. If unchecked they isolate the priming system, and the prime is lost. A properly designed automatic priming system fully protects critical components against flooding. LYNN’s system designs incorporate protection from flooding and carryover. The use of external separators is actually more of a nuisance than an asset.
The NPSHR of my pump is greater than the NPSHA of my installation. Can a priming system be used to increase the NPSHA so that my pump will not cavitate?
No, a priming system does not change the NPSHA of a given installation.