The main components of the reciprocating pump: pump cylinder, piston, piston rod and suction valve, discharge valve.
Working principle: When the piston moves from left to right, negative pressure is formed in the pump cylinder, and the liquid in the storage tank enters the pump cylinder through the suction valve. When the piston moves from right to left, the liquid in the cylinder is squeezed, the pressure increases, and it is discharged from the discharge valve. The piston reciprocates once, and each sucks and discharges the liquid once, which is called a working cycle; this kind of pump is called a single-acting pump. If the piston goes back and forth once, and the liquid is sucked and discharged twice, it is called a double-action pump. The movement of the piston from one end to the other is called a stroke.
The flow of the reciprocating pump has nothing to do with the head, but is related to the size of the pump cylinder, the stroke of the piston and the number of reciprocations. The theoretical flow of the single-acting pump is QT=Asn The actual flow of the reciprocating pump is smaller than the theoretical flow, and decreases with the increase of the head, which is caused by leakage.
The pressure head of the reciprocating pump has nothing to do with the flow rate of the pump and the geometric size of the pump, but is determined by factors such as the mechanical strength of the pump and the power of the prime mover.
Reciprocating pump installation height and flow adjustment
The reciprocating pump does not need to be filled with liquid when starting, because the reciprocating pump has self-priming ability, but its suction vacuum height also changes with the atmospheric pressure, liquid properties and temperature in the area where the pump is installed, so the installation height of the reciprocating pump is also limited. .
The flow of the reciprocating pump cannot be regulated by the valve on the discharge pipeline, but should be realized by using a bypass pipe or changing the number of reciprocations of the piston and changing the stroke of the piston.
The valve in the discharge line must be opened before the reciprocating pump is started. The piston of the reciprocating pump is connected to the prime mover by the connecting rod crankshaft. The prime mover can be either an electric motor or a steam engine.
The reciprocating pump is suitable for the transportation of high pressure head, small flow and high viscosity liquid, but it is not suitable for the transportation of corrosive liquid. Sometimes it is directly driven by a steam engine to transport flammable and explosive liquids.