Performance parameters of slurry pump
The theoretical flow rate (QT) of slurry pump is related to piston diameter, stroke and reciprocating times, but not to push out pressure
The theoretical flow rate of single acting slurry pump is calculated according to formula (2-1)
Where a is the cross-sectional area of piston, m;
S --- piston stroke, m;
--- speed of reciprocating pump.
The theoretical flow of double acting reciprocating piston pump is calculated according to formula (2-2)
Where a - cross sectional area of piston rod, M2
The actual average flow rate of reciprocating pump is smaller than the theoretical value,
In the formula, η V --- volumetric efficiency, which is mainly caused by the lag of valve opening and closing, and the leakage of valve and piston stuffing box
The results were compared with those of the control group.
The instantaneous flow of slurry pump depends on the product of piston cross-sectional area and piston instantaneous velocity. Because of the constant change of piston instantaneous velocity, its flow is not uniform. In actual production, in order to improve the flow uniformity, we can add an air chamber, and use the compression and expansion of air to store the discharged liquid, so as to improve the flow uniformity. The instantaneous flow of multi cylinder pump is equal to the sum of the same instantaneous flow of each cylinder. As long as the relative position of each cylinder crank is appropriate, the flow can be more uniform.
Like centrifugal pump, the head of reciprocating piston pump is also the energy added to the unit mass of liquid by the pump, which is called the head or pressure head of reciprocating piston pump
Because is presses out the liquid by the extrusion action, to the reactivation plug pump's lift may be arbitrarily high, has nothing to do with the flow. But in fact, due to the limited strength of structural materials, the components in the pump have leakage, so the head of reciprocating pump still has a limit, and if the head is too large, the motor or transmission mechanism will be damaged due to excessive load.
The discharge capacity of reciprocating piston pump is related to the displacement of piston, but has nothing to do with the condition of pipeline. This kind of property is called positive displacement characteristic, which must be called positive displacement characteristic. The flow rate of positive displacement can't be regulated by outlet valve.
3. Power and efficiency
The effective power PE of slurry pump is: