The Piston Pump Pneumatic
Piston pumps are a high-precision way to transfer liquids. They also produce a high level of pulsating flow, which is addressed with a pulsation dampener. However, they can be expensive and require a large investment to maintain.
The pistons are offset from each other by a reaction ring to reciprocate. The amount of time they spend on each piston pump pneumatic stroke determines the displacement of the pump.
Compressed air supply
The piston pump pneumatic is a versatile tool that uses compressed air to transfer fluids. It can be used for a variety of applications, including spraying paints and adhesives. It is also ideal for transferring low, medium, and high-viscosity oil. Its reciprocating motion allows for continuous operation and can handle a wide range of fluid viscosities.
The cylinder in a pneumatic piston pump is turned by the drive shaft, which causes the piston shoes to bear against an angled swash plate (Figure 3-16). This action forces the pistons to reciprocate up and down. The pistons pass the inlet port during the upstroke and the outlet port during the downstroke.
The force of the instroke is less than the outstroke, as the piston’s effective cross sectional area on the air side is smaller than that on the fluid side. The size of the piston rod can vary, but it should be sized big enough to provide adequate strength. This ensures that the pressure on the piston is high, but it should not be too high to cause damage.
Intake stroke
The intake stroke of a piston pump pneumatic consists of the movement of compressed air to fill the pump with power fluid. The force of this air can be adjusted to control the flow and pressure of the pumped power fluid. The adjustment is based on the distance between the center point of the rotor and that of the cylinder block, which can be varied. The varying distance between these centers produces different piston strokes and delivery volumes.
The rotary piston is housed in the cylinder and moves within it by means of a hinge pin. One end of the inlet valve (a cylinder) is constantly open to the work chamber, while the other end continuously contacts (or rides on) the rotary piston. As the drive shaft turns, this contact causes the rotary piston to reciprocate.
During the intake stroke, the inlet valve closes to prevent backflow, and the piston’s forward motion compresses the power fluid inside the cylinder, increasing its pressure. When the compression stroke is complete, the outlet valve opens and pressurized fluid flows out of the cylinder and into the discharge line.
Compression stroke
The compressor stroke is when the piston moves down in its cylinder. It reduces the volume of its chamber and compresses the adhesive in it, forcing fluid out through a discharge valve. This is the first stage of the pumping process.
The next step in a double-acting piston pump is the intake stroke. As the piston moves forward, it creates a negative pressure in the chamber behind it, which draws fluid into the pump through an inlet valve. The pump then begins its power stroke, which dispenses the fluid.
During this process, the force and rotational speed transferred to the piston are proportional to the distance between the rotor center and the piston center. If the rotor is aligned with the piston center (as shown in view A of Figure 3-13), there is no pumping action. Conversely, if the piston is centered in the cylinder, there is no suction or discharge. This is because the cylinder’s pressure rapidly changes with high frequency, which can cause vibration of the cylinder and swash plate. This vibration is avoided by ensuring the swash plate has an adequate clearance.
Discharge stroke
The discharge stroke of a piston pump occurs when piston pump pneumatic supplier the air distribution system redirects compressed air to the opposite side of the piston. This pushes against the diaphragm connected to the piston and reduces the volume of the chamber, compressing the fluid inside. The resulting pressure forces the fluid out through a discharge valve and into the pump outlet.
The upper piston also moves down, causing spent power fluid to enter the lower end of the valve body. This power fluid is then pushed by the yoke return spring and the compensator valve to decrease the pump displacement.
The piston velocity during this cycle is controlled by the size of the hole (known as an orifice) in the part that bumps the yoke off its seat at the end of the upstroke. The smaller the orifice, the slower the upstroke for a given injection pressure. This control mechanism prevents damage to the cylinder and pumping system. This type of piston pump is typically used in oil extraction applications. It can be single or double acting, with the latter requiring the piston to move in both directions to complete a full pumping cycle.
Continuous operation
The reciprocating action of the piston within the cylinder alternately draws in and discharges fluid, creating a continuous flow. This is a significant advantage over plunger pumps, which must have an external suction and discharge valve. The piston pump can also withstand high pressures without suffering from fluid surge. It is also able to handle fluids with varying viscosities, making it suitable for many applications. However, it is important to note that the pump should be fitted with a pressure unloader and a regulating valve for safety reasons. These devices reduce pulsations and vibrations in the pipework, thereby extending the life of the hydraulic components downstream from the pump.
In addition, the speed of the pump can be controlled by adjusting the size of the hole, or orifice, in the part that bumps the reversing valve off its seat at the end of the upstroke. The smaller the orifice, the slower the pump will stroke for a given injection pressure. Separation of power fluid from the pumped liquid is achieved by metal-to-metal seals around the middle rod. If these seals leak, it can result in reduced pump speed and efficiency.