Reciprocating pumps are positive displacement pumps that use a rotating or reciprocating movement of one or more pistons in a cylindrical housing, and a connection between the pump inlet and outlet. The reciprocating pump works in a similar way to a piston engine—one or more pistons move back and forth within the pump housing. The movement of the pistons forces fluid in and out of the pump, creating a vacuum which draws fluid in from the inlet and expelling it from the outlet.
In a single-acting (SA) reciprocating pump, pistons move back and forth within the pump’s housing. The upstroke of the piston draws liquid in from the inlet port, while the downstroke forces liquid out of the outlet port. The pressure of the delivered liquid depends on the distance the piston moves and the size of the piston.
Double-acting (DA) reciprocating pumps have two pistons that move in opposite directions. As one piston is extended, it draws liquid in from the inlet port. As the second piston retracts, liquid is forced out of the outlet port. These types of pumps can produce higher pressure, depending on the size of the pump and the displacement of the pistons.
Reciprocating pumps are well-suited for a variety of applications, including water supply, irrigation, fire protection and general industrial processes. The simple construction, wide range of sizes and broad operating range of these pumps make them highly versatile. Reciprocating pumps are also able to produce high pressures and can accommodate fluids with high viscosity and low lubricity.
The construction of a reciprocating pump is relatively simple. It generally consists of a cylindrical housing with inlet and outlet ports, a connecting rod, and one or more pistons. The connecting rod is attached to the piston and drives the pistons back and forth within the housing as it rotates. Valves and seals located between the ports help to control the flow of fluid in and out of the housing.
The working principle of a reciprocating pump can be divided into four consecutive stages. The first stage is the suction stroke, where the piston moves to the lower part of the cylinder, creating a vacuum which causes fluid from the inlet port to be pulled into the inner chambers of the pump.
The second stage is the compression stroke, where the piston is moved to the upper part of the cylinder, forcing the fluid to compress.
In the third stage, the power stroke, the connecting rod rotates, moving the piston to the lower part of the cylinder and forcing the compressed fluid out of the pump.
The fourth stage is the return stroke, where the piston returns to the upper part of the cylinder in preparation for the next cycle.
The performance of a reciprocating pump can be improved by adding devices such as valves and booster pumps. Valves help control the flow of fluid, while booster pumps increase the pressure of the delivered fluid.
Reciprocating pumps are simple to operate and maintain, making them a popular choice for various applications, from water supply to industries such as pharmaceuticals and oil production. These pumps are also highly reliable and can operate for extended periods of time with minimal downtime.
