What is a high pressure plunger pump

The operating pressure of the high-pressure plunger pump should generally be between 10MPa and 100MPa. It belongs to a positive displacement pump, which uses the periodic change of the volume in the working chamber to achieve the purpose of conveying liquid; the mechanical energy of the prime mover is directly converted into the pressure energy of the conveying liquid through the pump; the capacity of the pump only depends on the volume change value of the working chamber and its The number of changes per unit time is theoretically independent of the discharge pressure. The reciprocating pump uses the reciprocating motion of the piston in the working chamber of the liquid cylinder (or the periodic elastic deformation of flexible elements such as diaphragms and bellows in the working chamber) to periodically change the volume of the working chamber. Structurally, the working chamber of triplex plunger pump the reciprocating pump is separated from the outside world by means of a sealing device, and is communicated or closed with the pipeline through the pump valve (suction valve and discharge valve).

High pressure plunger pump
Features of high pressure plunger pump
1. Instantaneous flow is pulsating
This is because in the plunger pump, the suction and discharge of the liquid medium are alternately carried out, and the speed of the piston is constantly changing during the displacement process. In a pump with only one working chamber, the instantaneous flow of the pump not only varies with time, but is discontinuous. With the increase of the working chamber, the pulsation amplitude of the instantaneous flow becomes smaller and smaller, and it can even be regarded as turbulent flow in practice.
2. The average flow is constant
Theoretically, the flow rate of the pump only depends on the main structural parameters of the pump, n (reciprocating times per minute), S (piston stroke), D (piston diameter), Z (piston number), independent of the discharge pressure, and related to the conveying medium.
Physical and chemical properties such as temperature and viscosity are irrelevant. So the flow rate of the pump is constant.
3. The pressure of the high-pressure pump depends on the characteristics of the pipeline
The discharge pressure of the high-pressure plunger pump cannot be defined by the pump itself, but depends on the piping characteristics of the pump device, and has nothing to do with the flow rate. That is to say, if the conveyed liquid is considered to be incompressible, then in theory, it can be considered that the discharge pressure of the reciprocating pump will not be limited, and any desired discharge pressure of the high-pressure pump can be established according to the piping characteristics of the pump device. . Of course, all reciprocating pumps have a stipulation on the discharge pressure of the pump. This does not mean that the discharge pressure of the pump will not increase, but just means that due to the limitation of the rated power of the prime mover and the structural strength of the pump itself, it is not allowed to Use beyond this discharge pressure.
4. Strong adaptability to conveying medium
In principle, the plunger pump can transport any medium, and is almost not limited by the physical and chemical properties of the medium. Of course, due to the limitations of the material and manufacturing process of the liquid end and the sealing technology, there are sometimes situations that cannot be adapted.
5. Good self-priming performance
The high-pressure plunger pump not only has good suction performance, but also has good self-priming performance. Therefore, for most reciprocating pumps, it is usually not necessary to prime the pump before starting. The machine has high efficiency and energy saving.
Flow rate of high pressure plunger pump
Theoretical flow of high pressure pump: Qt=AsnZ
The theoretical flow of the Qt pump in the formula; A cross-sectional area of ​​the plunger (or piston); S stroke; n crankshaft speed (or the number of reciprocations per minute of the piston)
The actual flow of the high-pressure pump: Q=Qt-Q.
In the formula, the flow rate of the Q pump; the theoretical flow rate of the Qt pump; the flow loss of the Q pump. The factors that cause the flow loss of the pump are: volume loss due to liquid compression or expansion; volume loss due to valve lag when closing; volume loss due to leakage through the sealing surface due to lax valve closure; , volume loss due to leakage of piston rod or piston ring.