In this Article we can do a simple model of piston pump using syringe.
Brief:
The piston Pump classified one of positive displacement type that transfer the fluid with high pressure and high volumetric efficiency.
Generally the main function of pumps is to convert the mechanical power to hydraulic power, where the pump works through rotation movement generated from motor or engine, then the rotation movement moves the mechanism of pump to transfer fluid from point to another with flowrate and pressure which is "Hydraulic Power".
Theory of operation
- The piston pump works by reciprocating mechanism which converts the rotation movement of crank shaft to reciprocating movement of the piston inside cylinder.
- Reciprocating movement makes two steps in the piston pump:
1. Intake step that the piston suck the fluid from tank by negative pressure.
2. Discharge step that the piston push the fluid to the system with high pressure and high volumetric efficiency.
- The piston pump needs two “Non-return valves” to allow the fluid enter the cylinder during the intake step, and allow the fluid to go out from the cylinder during discharge step.
What’s Volumetric efficiency?
It indicates the amount of leakage that takes place within the pump; this involves considerations such as manufacturing tolerances and flexing of the pump casing under design pressure operating conditions.
Conclusion
The pump pushes the fluid to the system through the output valve, because the position of input valve doesn’t allow the fluid to out.
Otherwise when the pump suck the fluid the input valve allows the fluid to come from tank to the cylinder, and the output valve doesn’t allow suction.
Let’s Go Implementation
Now we can try to make a simple kit of piston pump using a very common components.
List of Components:
- Meccano Structure.
- Syringe.
- DC Motor.
- DC Battery 12V.
- Crank Shaft.
- Non return valve from spray.
- Syringe Hoses.
** you can find non-return valve inside the head of spray.
just disassemble the head of spray carefully and use the check valve inside.
Piston Pump Kit in Action
Improvement
you can improve the piston pump by 2 methods.
1. Closed Loop
by using a sensor that can count the number of DC motor turns, you can control the volume witch out from the pump.
2. Open Loop
in this way you can replace the DC motor by the stepper motor without using sensors, just control the movement of the stepper motor by number of pulses.
Piston Pump Formula
The piston pump controlled by an equation, the input is an angle of the motor and the output is the volume of fluid.
References
- Fluid Power with Applications, Author: Anthony Esposito, Seventh Edition
Get the book from link below
https://www.noon.com/egypt-en/fluid-power-with-applications-7/N32255758A/p?gclid=Cj0KCQjwnJaKBhDgARIsAHmvz6cD5o0YkG-UH84Zaicu6Qu1BI44hdjG9oJmzxTNFu5JEtTaVjZYZbQaAifLEALw_wcB
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