High pressure plunger pump pressure should generally be between 10MPa ~ 100MPa. It is a positive displacement pump, with the help of the cyclical changes in the volume of the working chamber to achieve the purpose of conveying liquid. The mechanical energy of the prime mover can be directly transformed into the pressure energy of the liquid delivered by the pump. The capacity of the pump depends only on the variation of working chamber volume and its The number of changes in the unit of time, in theory, has nothing to do with the discharge pressure. Reciprocating pumps are cyclical changes in the volume of the working chamber by means of reciprocating motion of the piston in the working chamber of the cylinder (or by periodic elastic deformation of flexible elements in the working chamber, such as membranes and bellows). Structurally, the working chamber of the reciprocating pump is separated from the outside by a sealing device, and communicates with the pipeline through a pump valve (suction valve and discharge valve). Its characteristics are summarized as follows: 1. Instantaneous flow is pulsatile This is because in the plunger pump, liquid medium suction and discharge process is alternating, and the piston in the displacement process, its speed is constantly changing. In pumps with only one working chamber, the instantaneous flow rate of the pump varies not only over time but also over time. With the increase of the working chamber, the instantaneous flow rate of the pulse is getting smaller and smaller, and even in practical terms can be considered a steady flow. 2. The average flow rate is constant. In theory, the pump flow depends only on the pump's main structural parameters n (reciprocations per minute), S (piston stroke), D (piston diameter), Z (piston number), and discharge pressure Has nothing to do with the transport medium temperature, viscosity and other physical and chemical properties. So pump flow is constant. 3. Pump pressure depends on pipe characteristics The discharge pressure of the plunger pump can not be limited by the pump itself, but depends on the piping characteristics of the pump unit and is independent of the flow rate. That is, if the delivery liquid is considered to be incompressible, it is theoretically conceivable that the discharge pressure of the reciprocating pump is not subject to any limitation, and any desired discharge pressure of the pump can be established depending on the piping characteristics of the pump unit. Of course, all reciprocating pumps have a pump discharge pressure requirement, which does not mean that the pump discharge pressure will not increase any longer, but merely because of the prime mover rated power and the pump itself, the structural strength limits are not allowed Exceed this pressure of discharge use. 4. Strong adaptability to conveying medium Piston pumps can transport any medium in principle, with almost no restrictions on the physical and chemical properties of the medium. Of course, due to the fluid side of the material and manufacturing processes and sealing technology limitations, and sometimes also encounter can not adapt to the situation. 5. Has a good self-priming performance Plunger pump not only has good inhalation performance, but also good self-priming performance. Therefore, for most reciprocating pumps, it is usually not necessary to prime the pump before starting. Machine efficiency, energy saving. 6. High-pressure piston pump flow pump theoretical flow: Qt = AsnZ Where Qt pump theoretical flow; A plunger (or piston) cross-sectional area; S stroke; n crankshaft speed (or plunger reciprocation per minute) Z number (plunger or piston number) The actual flow of the pump: Q = Qt-Q. Type Q pump flow; Qt pump theoretical flow; Q pump flow loss. Factors that contribute to pump flow loss include: volume loss due to liquid compression or expansion; volume loss due to valve lag due to closure; volume loss due to leakage through the sealing surface due to unsystematic valve closure; , Piston rod or piston ring leakage caused by the volume loss. 7. Pump instantaneous flow Single-cylinder single-acting pump flow curve: Single-acting triple-cylinder pump flow is a single-cylinder single-acting pump flow in the three phases of the superimposed curve is as follows: 8. Pump power pump effective power: Unit time, the pump discharge of liquid from the pump is called the effective power. Ne = PQ where Ne effective power, P total pressure, Q flow. After substitution into the unit becomes: Ne (KW) = 1 / 36.7 × P (Kgf / cm2) × Q (m3 / h). Considering the power loss caused by transmission efficiency, mechanical friction, volumetric efficiency and medium temperature rise, N = 1 / (0.85-0.9) N for low pressure reciprocating pump when selecting the power of the prime mover. For high pressure reciprocating pump, N = 1 / (0.75-0.85) N. Reciprocating Pump Applications Piston pumps are mainly suitable for high pressure and low flow, requiring constant or constant pump flow, delivering a wide range of different media in proportion, or requiring good suction or self-priming performance. In the current energy-scarce world, reciprocating pumps, as energy-saving products, are widely used in many industries, such as energy mining, petroleum refining, food and drug processing. Such pump structure is more complex, strong supporting and poor versatility, variety and small batch.