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Selection Guide
Learn how miniature diaphragm pumps work, where micro diaphragm pumps are used, and how to compare Keyto models by media, flow, pressure, voltage, power, and motor life.
How It Works
A miniature diaphragm pump is a compact positive-displacement pump. A motor drives an eccentric mechanism, the diaphragm moves back and forth, and inlet/outlet check valves control the direction of liquid or gas flow. The diaphragm also separates the pumped media from the motor side, helping deliver clean, oil-free transfer.
The DC motor rotates an eccentric (off-centre) wheel, converting rotary motion into a reciprocating push-pull stroke on the diaphragm connecting rod.
As the diaphragm retracts, pump-chamber volume increases. Pressure drops below atmospheric, closing the outlet valve and opening the inlet valve to draw fluid in.
As the diaphragm advances, chamber volume decreases. Pressure builds, closing the inlet valve and forcing fluid out through the outlet check valve.
The diaphragm forms a hermetic barrier between the fluid chamber and the motor side — no lubrication contacts the pumped media, enabling use in medical, food-grade, and analytical applications.
Application Industries
Different applications require different flow rates, pressure or vacuum levels, wetted materials, motor life, and control methods. Use the guide below to match the pump type to the system requirement.
Blood analyzers, POC diagnostics, washing, aspiration, and waste liquid handling need clean, stable, oil-free flow.
7121-37121-6Sampling, reagent handling, rinsing, and benchtop liquid transfer often require compact size and stable output.
7521-37122Model Comparison
Compare Keyto miniature diaphragm pump models by media, max flow, pressure or vacuum, voltage, power, and motor configuration.
| Model | Media | Max Flow | Pressure / Vacuum | Voltage | Power | Motor / Life | Details |
|---|---|---|---|---|---|---|---|
| 7521-3 | Liquid | ≥300 mL/min | Output ≥600 kPa Suction ≤-40 kPa |
12V / 24V DC | <12W | Long-life DC motor 10,000H |
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| 7121-3 | Liquid / Gas | 300 mL/min | Output ≥200 kPa Suction ≤-80 kPa |
12V / 24V DC | 7W | BLDC, PWM optional 10,000 hrs |
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| 7121-6 | Liquid / Gas | 600 mL/min | Output ≥200 kPa Suction ≤-80 kPa |
12V / 24V DC | 7W | BLDC, PWM optional 10,000 hrs |
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| 7122 | Liquid | 1,200 mL/min | Output ≥200 kPa Suction ≤-80 kPa |
24V DC | 15W | DC motor >800H |
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| 7102 | Gas | 8,000 mL/min | Output ≥120 kPa Vacuum ≤-70 kPa |
12V / 24V DC | 14W | Brushless motor >10,000 hours |
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| 7101 | Gas | 5,000 mL/min | Output ≥150 kPa Vacuum ≤-65 kPa |
12V / 24V DC | 12W | DC motor >5,000H |
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| 7121-3 Brushed | Liquid / Gas | 300 mL/min | Output ≥200 kPa Suction ≤-80 kPa |
12V / 24V DC | 7W | Brush motor 3,000H |
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| 7121-6 Brushed | Liquid / Gas | 600 mL/min | Output ≥200 kPa Suction ≤-80 kPa |
12V / 24V DC | 7W | Brush motor 3,000H |
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Values are compiled from published product pages. Final pump choice should be validated against actual medium, temperature, duty cycle, and system resistance.
Knowledge Hub
Use these guides to go deeper into pump selection, application design, and integration details.
Application
How pumps support washing, aspiration, and waste handling in diagnostic instruments.
Application
Review new application directions across compact fluid control systems.
Selection
Define medium, target flow, pressure or vacuum, voltage, duty cycle, and material compatibility before selecting a model.
FAQ
A miniature diaphragm pump is a positive-displacement pump that uses a flexible diaphragm driven by an eccentric mechanism to move gas or liquid. The diaphragm alternately expands and compresses the pump chamber, drawing fluid in through an inlet check valve and expelling it through an outlet check valve. Because the pumped media never contacts the motor, these pumps deliver clean, oil-free flow — making them ideal for medical, laboratory, and analytical applications.
Diaphragm pumps use a reciprocating membrane and check valves; they are better at generating higher pressures and handle gas or liquid cleanly. Peristaltic pumps squeeze a flexible tube; they are preferred when zero contact with wetted parts is critical (e.g. aggressive chemicals or sterile bio-fluids). For compact gas handling, pressure generation, and long service life with minimal maintenance, miniature diaphragm pumps are typically the better choice.
Brushless-motor pumps (standard series) offer longer service life, lower maintenance requirements, and lower electrical noise — better for continuous-duty or high-cycle OEM applications. Brushed-motor variants (with-brush series) have lower upfront cost and simpler drive electronics, making them suitable for lower duty-cycle or cost-sensitive designs where long-term lifespan is less critical.
Keyto miniature diaphragm pumps cover a wide range depending on model. Flow rates span from a few mL/min for precision liquid dosing up to standard gas-sampling flow rates. Pressure capability ranges from standard low-pressure models up to the high-pressure 7521-3 series. Consult the specification table above or download the datasheet for exact values.
Yes. All Keyto miniature diaphragm pumps are oil-free by design. The flexible diaphragm creates a hermetic barrier between the fluid chamber and the motor-drive side, so no lubricants contact the pumped media. This is essential for medical diagnostics, food-grade, and analytical applications.
Brushless-motor models are designed for continuous or high duty-cycle operation and typically offer significantly longer service life than brushed variants. Exact service-life figures depend on voltage, pressure, media, and operating temperature — contact the Keyto engineering team for application-specific guidance.
Yes. Keyto offers OEM customisation including voltage variants, port configurations, material selection for wetted parts (PTFE, EPDM, silicone), mounting options, and cable/connector specifications. Contact the Keyto engineering team with your flow rate, pressure, media, and duty-cycle requirements.
Keyto miniature diaphragm pumps are engineered for low vibration and low acoustic noise — a key requirement for bedside medical devices and laboratory bench instruments. Typical noise levels are below 45 dB(A) at standard operating conditions. Refer to individual model datasheets for tested values at specific operating points.
It depends on motor type, pressure load, temperature, and duty cycle. Brushless models are usually better for longer operation.
Keyto diaphragm pumps can be configured with PTFE diaphragms and fluoropolymer check valves for handling mild acids, bases, and solvents. For highly aggressive media, contact the engineering team to confirm material compatibility before specifying.
Tell Keyto your media, flow rate, pressure or vacuum requirement, voltage, duty cycle, and installation space.
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