Basic Knowledge of Diaphragm Pumps
1. What is a Diaphragm Pump?
A diaphragm pump draws in and discharges liquids by moving a rubber or resin “diaphragm” back and forth.
Think of it like a manual air pump, but it moves liquids or chemicals instead of air.
📌 Operation of Diaphragm Pump (Video)
- The rubber diaphragm moving side to side acts as a substitute for a piston
- When the diaphragm is pulled, it draws in liquid
- When the diaphragm is pushed, it discharges liquid
- Both the suction port and the discharge port are equipped with check valves, so the liquid does not flow backward.
2. How a Diaphragm Pump Works
- Air-Operated Type: Uses compressed air to move the diaphragm.
- Motor-Driven Type: Uses motor rotation to move the diaphragm.
In other words, the basic principle is the same; only the power source differs.
3. Advantages
- ✅ Liquid and chemicals rarely contact metal parts inside the pump → Can handle corrosive chemicals.
- ✅ Self-priming capability → Can draw liquid even if the hose is empty.
- ✅ Handles liquids containing foreign matter or solids → Suitable for food, cosmetics, and chemical solutions.
- ✅ Seal-less design → Minimizes leakage and simplifies maintenance.
- ✅ High explosion safety with air-operated type → Safe to use in areas where open flames are prohibited.
4. Disadvantages
- ⚠️Air-operated type requires a large amount of compressed air → Higher running costs.
- ⚠️ Diaphragm wears or may be damaged → Regular replacement is necessary.
- ⚠️ Flow is pulsating (pumps in surges) → Not suitable for applications requiring a smooth, uniform flow.
5. Where is it used?
Diaphragm pumps are widely used across many industries.
- 🍫 Food Factories: Handles high-viscosity liquids such as chocolate, syrup, and sauces.
- 🚗 Automotive Factories: Transfers paints and chemical solutions.
- 🧴 Cosmetics Factories: Handles viscous products such as creams and lotions.
- 🔬 Chemical Factories: Handles corrosive liquids such as acids and alkalis.
- 🏭 Steel and Surface Treatment Plants: For waste liquid treatment and chemical supply.
6. Eichitwo’s Diaphragm Pump Lineup
Here is our product lineup
7. Main Products of Eichitwo
- High-Viscosity Transfer Diaphragm Pumps
- Snake Pumps
- Rotary Lobe Pumps
- High-Viscosity Transfer Sanitary Drum Pumps
- Floating Oil Recovery Skum Skimmers
- pH Neutralization Treatment Equipment
The company is especially strong in transferring high-viscosity liquids, chemicals, and in applications requiring heat resistance.
8. Summary
- Diaphragm pumps transfer liquids using the movement of a diaphragm.
- They are leak-resistant and can safely handle a wide variety of liquids.
- Used across many industries, from food and chemicals to steel manufacturing.
- However, attention is needed for compressed air consumption and periodic part replacement.
Summary
- “Pump Handbook” – Japan Industrial Machinery Association
- Technical Materials – Japan Pump Manufacturers Association
- Technical Materials – Eichitwo Co., Ltd.
