As a supplier of peripheral pumps, I've encountered numerous inquiries from customers regarding the issue of their pumps losing prime. This phenomenon can be quite frustrating as it disrupts the normal operation of the pump system. In this blog, I'll delve into the various factors that can cause a peripheral pump to lose prime and offer some insights on how to address them.
Air Leaks
One of the most common culprits behind a peripheral pump losing prime is air leaks in the suction line. Air leaks can occur at various points, such as loose fittings, cracks in the piping, or faulty seals. When air enters the suction line, it disrupts the normal flow of liquid into the pump, causing the pump to lose its prime.
To check for air leaks, inspect the suction line for any visible cracks or loose connections. Tighten any loose fittings and replace any damaged pipes or seals. You can also use a pressure gauge to check for any pressure drops in the suction line, which could indicate an air leak. If you suspect an air leak at a particular fitting but can't visually detect it, you can apply a soapy solution to the fitting and look for bubbles. Bubbles will indicate the presence of an air leak.
Insufficient NPSH (Net Positive Suction Head)
Another factor that can cause a peripheral pump to lose prime is insufficient Net Positive Suction Head (NPSH). NPSH is the difference between the absolute pressure at the pump suction and the vapor pressure of the liquid at the pumping temperature. If the NPSH available is less than the NPSH required by the pump, the liquid in the suction line can vaporize, leading to cavitation and loss of prime.
To ensure sufficient NPSH, it's important to properly size the suction line and keep the suction lift within the pump's specified limits. You may also need to consider the elevation of the pump relative to the liquid source, as well as the temperature and viscosity of the liquid. If you're unsure about the NPSH requirements of your pump, consult the pump manufacturer's documentation or a qualified engineer.
Clogged Suction Line
A clogged suction line can also prevent the pump from maintaining prime. Debris, such as dirt, sand, or leaves, can accumulate in the suction line over time, restricting the flow of liquid into the pump. This can cause the pump to lose its prime and eventually stop working.
To prevent a clogged suction line, install a strainer at the inlet of the suction line. The strainer will help to remove any large debris from the liquid before it enters the pump. Regularly clean the strainer to ensure that it remains free of debris. If the suction line becomes clogged, you may need to disassemble the pump and clean the suction line thoroughly.
Improper Priming Procedure
Peripheral pumps require proper priming to operate effectively. If the priming procedure is not followed correctly, the pump may not be able to establish and maintain prime. The priming process involves filling the pump housing and the suction line with liquid to remove any air.
To prime a peripheral pump, follow these steps:
- Ensure that the pump is turned off and the power supply is disconnected.
- Close the discharge valve.
- Open the priming port or the air vent valve on the pump housing.
- Slowly fill the pump housing and the suction line with liquid until it overflows from the priming port or the air vent valve.
- Close the priming port or the air vent valve.
- Open the discharge valve.
- Turn on the pump and check for proper operation.
Mechanical Issues
Mechanical issues within the pump itself can also cause it to lose prime. For example, a worn or damaged impeller can reduce the pump's ability to create the necessary suction to maintain prime. Similarly, a faulty shaft seal can allow air to enter the pump housing, leading to loss of prime.
Regular maintenance of the pump is essential to prevent mechanical issues. Inspect the impeller for any signs of wear or damage and replace it if necessary. Check the shaft seal for leaks and replace it if it's worn or damaged. Lubricate the pump bearings as recommended by the manufacturer to ensure smooth operation.
Viscosity and Temperature of the Liquid
The viscosity and temperature of the liquid being pumped can also affect the pump's ability to maintain prime. If the liquid is too viscous, it can be difficult for the pump to create the necessary suction to draw the liquid into the pump. Similarly, if the liquid is too hot, it can vaporize more easily, leading to cavitation and loss of prime.
When selecting a peripheral pump, consider the viscosity and temperature of the liquid you'll be pumping. Choose a pump that is designed to handle the specific properties of the liquid. You may also need to adjust the operating conditions, such as the flow rate or the pressure, to ensure optimal performance.
Conclusion
In conclusion, there are several factors that can cause a peripheral pump to lose prime, including air leaks, insufficient NPSH, clogged suction lines, improper priming procedures, mechanical issues, and the viscosity and temperature of the liquid. By understanding these factors and taking appropriate preventive measures, you can minimize the risk of your peripheral pump losing prime and ensure its reliable operation.
At our company, we offer a wide range of high - quality peripheral pumps, including the Brass Impeller Vortex Pump, the Copper Wire Vortex Pump, and the High Pressure QB Peripheral Vortex Water Pump For Clean Water. Our pumps are designed to meet the diverse needs of our customers and are backed by our expertise and excellent customer service.
If you're experiencing issues with your peripheral pump losing prime or are looking to purchase a new pump, we'd be more than happy to assist you. Contact us today to discuss your requirements and let's start a productive conversation about your pump needs.
References
- Pump Handbook, Karassik, I. J., et al.
- Hydraulic Institute Standards for Centrifugal, Rotary and Reciprocating Pumps.
