Piston Pump

Content
1. What is piston pump?
2. How does piston pump work?
3. Piston pump parts and function
4. Types of pistion pump
    4.1. Single piston pump
    4.2. Horizontal piston pump
    4.3. Axial piston pump
    4.4. Swash plate piston pump
    4.5. Radial piston pump
    4.6. Hydraulic piston pump
5. Piston pump specification
    5.1. Triple piston pump
    5.2. Variable displacement piston pump
    5.3. Radial piston pump
6. How to use Piston pump?
7. How to maintain piston pump?
8. How to buy piston pump?

Piston pump is a kind of reciprocating pump and an important device of hydraulic system. It relies on the reciprocating movement of the plunger in the cylinder to make the volume of the sealed working chamber change to achieve oil suction and pressure. The plunger pump has the advantages of high rated pressure, compact structure, high efficiency and easy flow adjustment.
Piston pumps are widely used in high-pressure, high-flow and flow-regulated applications, such as laboratory experiments, industry, agriculture and other fields, as well as hydraulic presses, construction machinery and ships.

The working principle of plstion pump is that relies on the reciprocating movement of the plunger in the cylinder to make the volume of the sealed working chamber change to realize oil suction and pressure. When the plunger pump works, under the action of the cam and plunger spring on the camshaft of the injection pump, the plunger is forced to make upward and downward reciprocating motion, so as to complete the task of pumping oil. When the plunger is pulled outward, the pressure inside the working chamber decreases, the export valve closes, and when it is lower than the import pressure, the import valve opens and the liquid enters; when the plunger is pushed inward, the working chamber pressure rises, the import valve closes, and when it is higher than the export pressure, the export valve opens and the liquid is discharged.be changed by adjusting the angle of inclination of the swash plate.

1. Power side
* Crankshaft
Crankshaft is one of the key parts in this pump. The crankshaft adopts the integral type of crankshaft, which will complete the key step from rotary motion to reciprocating linear motion, and in order to make it balanced, each crankshaft shank pin is 120° from the center.
Connecting rod
The connecting rod transmits the thrust on the plunger to the crankshaft, and converts the rotational motion of the crankshaft into the reciprocating motion of the plunger, whose rod cross-section takes the shape of an I-beam, with the large head being of the split type, the shaft tile adopting the form of a counterpart thin-walled tile, and the small head tile adopting the sleeve type, and is positioned with it.
* Crosshead
The crosshead connects the swinging connecting rod and the reciprocating plunger, which has a guiding role, and it is closed connection with the connecting rod and connected with the plunger clamp.
* Floating sleeve
The floating sleeve is fixed on the machine base, which plays the role of isolating the oil tank and the dirty oil pool on the one hand, and plays the role of a floating support point for the crosshead guide rod on the other hand, which can improve the service life of the moving sealing parts.
* Seat
The seat is the force member for mounting the power end and connecting the hydraulic end part.

2. Hydraulic side
* Pump head
The pump head is made of stainless steel forged as a whole, the suction and discharge valves are arranged vertically, the suction hole is at the bottom of the pump head, the discharge hole is at the side of the pump head, which is connected with the valve cavity, simplifying the discharge piping system.
* Sealing function
The sealing function is connected to the pump head by flange, and the sealing of the plunger is in the form of rectangular soft packing of carbon fiber textile, which has good high pressure sealing performance.
* Plunger
* Inlet and Discharge Valves
Inlet and discharge valves and valve seats, suitable for conveying viscous liquids with low damping, conical valve structure, with reduced viscosity. The contact surface has high hardness and sealing performance to ensure that the inlet and discharge valves have sufficient service life.

Single piston pump is also known as single plunger pump, the main structural components are eccentric wheel, plunger, spring, cylinder body, two one-way valve. Between the plunger and the cylinder body hole to form a closed volume. Eccentric wheel rotation a turn, the plunger up and down reciprocating movement once, downward movement of oil absorption, upward movement of oil discharge. The volume of oil discharged in each revolution of the pump is called the displacement, and the displacement is only related to the structural parameters of the pump.
Horizontal piston pump.

Horizontal piston pump is a hydraulic pump that is installed by several plungers (such as triple piston pump) side by side, with 1 crankshaft through the connecting rod slider or by the eccentric shaft directly pushing the plunger to do a reciprocating motion to achieve suction and discharge of liquid. The emulsion pump in the hydraulic support system of a coal mine is generally a horizontal piston pump. The emulsion pump is used in coal mining face to provide emulsion for hydraulic support. The working principle relies on the rotation of the crankshaft to drive the piston to do a reciprocating motion to realize the suction and discharge of liquid.

Axial piston pump is piston pumps in which the direction of reciprocating motion of the piston or plunger is parallel to the central axis of the cylinder. The axial piston pump works by using the volume change generated by the reciprocating motion of the plunger in the plunger bore parallel to the drive shaft. Since the plunger and plunger bore are round parts, a high precision fit can be achieved, resulting in high volumetric efficiency.
The common types of axial piston pumps are variable displacement pump which is also named variable displacement piston pump and fixed displacement piston pump.

Swash plate piston pump is divided into two types: pressure-supplied type and self-priming type. Most of the pressure supply type hydraulic pump is used with an air pressure tank, hydraulic tank by air pressure supply, after each start of the machine, must wait for the hydraulic tank to reach the use of air pressure, before operating the machinery. If the hydraulic tank air pressure is not enough to start the machine, it will cause a pull-off phenomenon to the slide shoe inside the hydraulic pump, which will cause abnormal wear of the return plate and pressure plate inside the pump.

Radial piston pump can be divided into two categories: valve-dispensing flow and shaft-dispensing flow. The valve flow radial piston pump has a high failure rate, low efficiency, and other shortcomings. International the 70s and 80s the development of axial flow radial piston pump to overcome the shortcomings of the valve flow radial piston pump. Due to the characteristics of the structure of the radial pump, the fixed shaft-matched flow radial piston pump than the axial piston pump impact resistance, long life, and high control accuracy. Variable stroke short pump variable is in the variable plunger and limits plunger action, change the eccentric distance of the stator to achieve, and fixed in the maximum eccentric distance of 5-9mm (depending on the size of the displacement), the variable stroke is very short. And the variable mechanism is designed for high-pressure operation, controlled by the control valve. Therefore, the pump's response speed is fast. The radial structure design overcomes the problem of partial wear of the slide show of the axial piston pump, for example. Make its impact resistance greatly improved.

Hydraulic piston pump relies on air pressure to supply the hydraulic oil tank, and after each start of the machine, you must wait for the hydraulic oil tank to reach the use of air pressure before you can operate the machinery. Straight shaft swashplate piston pump is divided into two types of pressure-supplied self-priming oil type. Most of the pressure supply type hydraulic pumps use the tank with air pressure, there are hydraulic pumps themselves with oil filling sub-pump to provide pressure oil to the hydraulic pump inlet. Self-priming type hydraulic pump has a strong self-priming ability, without external oil supply.

Features:
1. Triple piston pump uses handle design, portable and lightweight, small and convenient, easy to move.
2. Shock-absorbing foot design, smooth shock absorption, cushioning shock absorption, easy maintenance.
3. Fine workmanship, surface painting treatment, fashionable and beautiful, not easy to rust.

Features:
1. Variable displacement piston pump is simple structure, small volume, low noise, and high efficiency.
2. Made of cast iron, non-corrosive pump body.

Features:
1. The structure of radial piston pump is solid, and high output force, stable and reliable performance, easy maintenance, and a wide range of applications.
2. Flexible and reliable, long service life.
3. Adopt an energy-saving motor, with high efficiency, and low energy consumption.
4. Small size, light weight, easy to carry.

1. The new piston pump should be washed with anti-corrosion grease on the pump before use, check whether the bolts at each connection are tightened, and do not allow any loosening.

2. Inject mechanical oil (GB3141-82) in the gearbox and transmission, and control the oil volume at the center line of the oil mark.

3. Move the metering pump by hand and make the plunger reciprocate for 1~2 large strokes. There must not be any jamming phenomenon. Then the pump stroke zero position corresponds to the zero position of the regulating table to prevent the drift of the regulating table pointer in transportation.

4. Open the valve on the import and export pipeline, start the motor, check the motor line, and make the pump rotate according to the specified rotation direction. Choose the large stroke to discharge the liquid, so that the air in the liquid cylinder body is completely exhausted.

5. Rotate the handle to calibrate the displacement of the piston pump. To be adjusted to the set displacement, the adjusting handle locking screw should be tightened to avoid impact loosening, causing changes in flow.

6. After the pump runs normally under normal pressure, gradually increase the discharge pressure to the rated value.

7. Check the leakage at the plunger packing, if the leakage amount is more than 10 drops per minute, the packing compression nut should be tightened appropriately, and the compression force should be appropriate to not jam the plunger and not leak.

8. Check the temperature rise phenomenon. The allowable temperature rise of the motor is 70℃, the lubricant temperature in the transmission box should not exceed 65℃, and the stuffing box temperature should not exceed 70℃. If the temperature rise is too high, it should be stopped to check, and then start running after troubleshooting.

1. Regularly replace the hydraulic oil and filter of the piston pump.

2. Regularly drain the oil tank dirt.

3. If the hydraulic oil of the plug
 pump is contaminated, especially when the hydraulic pump or hydraulic cylinder or motor is damaged, all the hydraulic oil must be replaced and the oil tank cleaned.

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