How does a mini diaphragm pump work?

A mini diaphragm pump is a type of positive displacement pump that uses a flexible diaphragm to transfer fluids. These pumps are often small and compact, making them suitable for various applications, such as medical devices, analytical instruments, and other low-flow, low-pressure fluid transfer tasks.

Here's how a mini diaphragm pump typically works:

1. Diaphragm: The pump consists of a flexible diaphragm, usually made of rubber or thermoplastic elastomer, which separates the pumping chamber from the fluid chamber.

2. Inlet and Outlet Valves: The pump has two check valves, one on the inlet side and one on the outlet side. These valves ensure a one-way flow of fluid through the pump.

3. Pumping Action: As the pump starts, the diaphragm moves back and forth due to the reciprocating motion of the pump mechanism. When the diaphragm moves in one direction (for example, to the right), it creates a vacuum in the pumping chamber while compressing the fluid in the fluid chamber.

4. Inlet Stroke: During the inlet stroke, the inlet valve opens, allowing the fluid from the source (e.g., a reservoir) to flow into the pumping chamber. The outlet valve remains closed at this point to prevent backflow.

5. Outlet Stroke: During the outlet stroke, the diaphragm moves in the opposite direction (for example, to the left). This action closes the inlet valve to prevent fluid from flowing back into the fluid chamber, and the outlet valve opens to allow fluid to be expelled from the pumping chamber to the destination (e.g., a discharge line).

6. Fluid Transfer: With each stroke of the diaphragm, a fixed volume of fluid is drawn into the pumping chamber during the inlet stroke and expelled during the outlet stroke. This creates a continuous flow of fluid through the pump.

7. Check Valve Function: The check valves ensure that the fluid flows in only one direction through the pump. They also prevent any backward flow, maintaining the pressure difference required for pumping action.

8. Sealing: The diaphragm acts as a seal between the pumping chamber and the fluid chamber, preventing any leakage of the fluid and ensuring that it moves in the desired direction.

The pumping rate and pressure of a mini diaphragm pump are influenced by various factors, such as the size and material of the diaphragm, the stroke length, and the speed of the reciprocating mechanism. These pumps are popular for their reliable and precise fluid transfer capabilities in small-scale applications.