Table of Contents
- 1 What is the purpose of recirculation line?
- 2 What is the use of recirculation line in boiler feed pump?
- 3 What is pump recirculation?
- 4 What is minimum flow line?
- 5 Why do you need to open the startup vent before starting the boiler?
- 6 How do I choose a boiler pump?
- 7 How can you prevent damage from internal suction recirculation?
- 8 What is of minimum recirculation flow for centrifugal pump?
What is the purpose of recirculation line?
Automatic recirculation valves, sometimes referred to as pump protection valves or minimum flow valves are installed on the outlet of a centrifugal pump discharge line. Their purpose is to prevent the pump from overheating by ensuring that there is a minimum flow through the pump at all times.
What is the use of recirculation line in boiler feed pump?
If the pump draw exceeds the NPSH, the inlet line pressure would drop below the vapor pressure, therefore resulting in flashing and cavitation. This recirculation line ensures that the boiler feedpump has the required flow available to protect the pump at all boiler load conditions.
Why is balancing line provided in BFP?
Balance line is used to balance the centrifugal pump shaft from axial thrust. Due to the axial thrust, pump bearings and internals will get damaged.
What is pump recirculation?
Abstract. Recirculation in centrifugal pumps is a flow reversal at the inlet or at the discharge tips of the impeller vanes. Through analysis and tests, it is now possible to determine the flow patterns that must exist to produce the observed results.
What is minimum flow line?
The minimum flow quoted for continuous operation is usually referred to as minimum continuous stable flow, or its more common abbreviation, MCSF. A pump’s MCSF is the flow below which the pump should not be operated continuously. The primary purpose of MCSF is to achieve satisfactory bearing and seal life.
What is the difference between circulation and recirculate?
As verbs the difference between circulate and recirculate is that circulate is to move in circles or through a circuit while recirculate is to (l) again.
Why do you need to open the startup vent before starting the boiler?
Leave a vent open to prevent pressure build up during the dry out period. Maintain the water level to replace any that leaves the drum due to the heating process.
How do I choose a boiler pump?
16 Steps to Proper Boiler-Feed-Pump Selection
- Determine the control method to be used.
- Calculate the base flow rate.
- Add for continuous boiler blowdown flow.
- Add for bypass flow, if required.
- Determine the total flow rate required.
- Calculate base head for the feed pump.
- Add all suction-piping head components.
What is offline leak?
Balance leak off line is used to balance the centrifugal pump shaft from axial thrust. During pump operation, especially in multistage centrifugal, suction will have less pressure compared to discharge.
How can you prevent damage from internal suction recirculation?
Other than avoiding the low flow suction recirculation zone all together, or selecting only low suction energy pumps, the normal first fix for a suction recirculation problem is to install external by-pass lines to bring the net flow rate above the start of suction recirculation.
What is of minimum recirculation flow for centrifugal pump?
If you need to operate a centrifugal pump back on the curve, the minimum suggested point is at 10\% of BEP (Best Efficiency Point). For example, a 620 pump with a full impeller has a BEP of 44\% at 24 GPM. Therefore, the minimum flow should be limited to 10\% of 24 or 2.4 GPM.