Classification of plunger pumps
The plunger pump is generally divided into a single plunger pump, a horizontal plunger pump, an axial piston pump and a radial piston pump.
1.Single plunger pump
The structural components mainly include an eccentric wheel, a plunger, a spring, a cylinder block, and two one-way valves. A closed volume is formed between the plunger and the cylinder bore. When the eccentric rotates one revolution, the plunger reciprocates up and down once, and moves downward to absorb oil, and moves upward to drain oil. The volume of oil discharged per revolution of the pump is called displacement, and the displacement is only related to the structural parameters of the pump.
2. Horizontal piston pump
The horizontal piston pump is installed side by side by several plungers (generally 3 or 6). It uses a crankshaft to pass the connecting rod slider or directly push the plunger to reciprocate the eccentric shaft to realize the suction and discharge of liquid. Hydraulic pump. They also use valve-type flow distribution devices, and most of them are dosing pumps. The emulsion pumps in the coal mine hydraulic support system are generally horizontal piston pumps. The emulsion pump is used for the coal mining face to provide an emulsion for the hydraulic support. The working principle relies on the rotation of the crankshaft to drive the piston to reciprocate to achieve liquid absorption and drainage.
The axial piston pump (English name: Piston pump) is a plunger pump in which the reciprocating direction of the piston or plunger is parallel to the central axis of the cylinder. The axial piston pump operates with a volume change produced by the reciprocating motion of the plunger parallel to the drive shaft within the plunger bore. Since the plunger and the plunger hole are both round parts, a high precision fit can be achieved, and the volumetric efficiency is high.
4. Straight axis swash plate
Straight-axis swash plate type piston pumps are divided into two types: pressure supply type and self-suction type. Pressure-supply type hydraulic pumps mostly use a gas tank with air pressure. The hydraulic oil tank that supplies oil by pressure must operate the machine after the hydraulic oil tank reaches the air pressure after each start of the machine. If the hydraulic fluid tank is not pressurized enough to start the machine, the sliding shoes in the hydraulic pump will be pulled off, which will cause abnormal wear of the return plate and the pressure plate in the pump body.
Radial piston pumps can be divided into two categories: valve distribution and shaft distribution. The valve distribution radial piston pump has the disadvantages of high failure rate and low efficiency. The shaft-distributing radial piston pump developed in the 70s and 80s in the world overcomes the shortcomings of the valve-distributing radial piston pump. Due to the characteristics of the radial pump structure, the radial piston pump with fixed shaft distribution has higher impact resistance, longer service life and higher control precision than the axial piston pump. The variable stroke short pump variable is realized by changing the eccentricity of the stator under the action of the variable plunger and the limit plunger, and the maximum eccentric distance is 5-9mm (depending on the displacement), the variable stroke is very short. . And the variable mechanism is designed for high pressure operation and is controlled by a control valve. Therefore, the pump responds quickly. The radial structural design overcomes the problem of eccentric wear such as axial piston pump shoes. Its impact resistance is greatly improved.
The hydraulic piston pump relies on the pneumatic oil supply tank. After each start of the machine, the hydraulic oil tank must be used to reach the operating air pressure before the machine can be operated. The straight-axis swash plate type piston pump is divided into two types: self-suction type of pressure oil supply type. Pressure-supply type hydraulic pumps mostly use a gas tank with air pressure, and the hydraulic pump itself has a charge pump to supply pressure oil to the oil pump inlet. The self-priming hydraulic pump has a strong self-priming capability and requires no external force to supply oil.