A double-acting piston pump suitable for cryogenic medium

Abstract

The invention designs a double acting piston pump applicable to a low temperature medium. The double acting piston pump applicable to the low temperature medium belongs to the technical field of conveying equipment for fluid substances, and comprises a pump shell, a main liquid inlet pipeline arranged on one end of the pump shell, and a liquid inlet cavity, an air cylinder and a piston rod arranged in the pump shell. The piston rod is subjected to pushing and pulling reciprocating motion in the air cylinder; at least two liquid inlet valves and at least two liquid outlet valves are arranged on the air cylinder; one-way valves are arranged on the liquid inlet valves and the liquid outlet valves; when the piston rod is subjected to pushing movement, one part of liquid inlet valve and liquid outlet valve are at a circulating state, and when the piston rod is subjected to pulling movement, the other part of liquid inlet valve and liquid outlet valve are at the circulating state. The piston pump is high in liquid feeding efficiency and stable in flow state, the manufacturing cost is reduced under the demand of through flow, and the loss of the pump and the pipelines can be effectively reduced.

Description

technical field [0001] The invention relates to the technical field of fluid conveying equipment, in particular to a double-acting piston pump suitable for low-temperature medium. Background technique [0002] In the transportation of cryogenic liquids (liquid oxygen, liquid nitrogen, liquefied natural gas, liquid carbon dioxide, etc.) or other media that require gas-liquid separation and pressurization, pumps are needed to drive the fluid flow. [0003] At present, reciprocating pumps are usually used to transport low-temperature medium in the market, and they are single-acting pumps, that is, equipped with one liquid inlet and one liquid outlet. This type of pump has the following defects: [0004] ①When the cylinder diameter or piston rod diameter is large, when the piston rod and piston reciprocate in the cylinder, the change of the volume space behind the piston will cause the inside of the pump chamber to be in a state of severe turbulence and gas-liquid mixing, result...

AI Technical Summary

Problems solved by technology

[0004] ①When the cylinder diameter or piston rod diameter is large, when the piston rod and piston reciprocate in the cylinder, the change of the volume space behind the piston will cause the inside of the pump chamber to be in a state of severe turbulence and gas-liquid mixing, resulting in pump failure. The efficiency of liquid intake is reduced;

[0005] ②The pump is a single-acting pump, which only performs work in half a cycle, and the liquid flow in the outlet pipeline is uneven, that is, the fluid flow in half a cycle is almost zero;

[0006] ③When it is necessary to increase the flow rate, there are only three ways to choose from: increasing the speed, increasing the cylinder diameter, and extending the stroke, and these methods will aggravate the phenomenon of turbulent flow and gas-liquid mixing inside the pump chamber, and further reduce the pump's intake. Liquid efficiency;

[0007] ④ When it is configured as a single-row single-acting pump (that is, there is only one cold-end fluid inlet), there will be disadvantages of large outlet pipeline pulsation and large motor power required;

[0008] ⑤ For single-acting pumps, under the same flow rate, speed and stroke, the bore diameter will inevitably be larger, and at the same time, the load of the pump and the pulsation of the pipeline will increase, the loss of the pump and pipeline will be increased, the service life will be reduced, and the pump life will be increased. Large equipment operating costs

[0009] The Chinese invention patent with the application publication number CN 105041634 A discloses an ultra-low temperature reciprocating piston pump. The airtightness of the piston pump is improved by a small cylinder with openings, thereby prolonging its life, but it does not fundamentally overcome the above defects

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