Views: 0 Author: Site Editor Publish Time: 2026-10-26 Origin: Site
Selecting a micro gear pump requires more than matching a pump's maximum flow rate to an equipment specification. A pump that is too small may fail to maintain the required flow under pressure, while an oversized pump can create unnecessary motor load, poor low-speed control, and inefficient operation.
For OEM equipment manufacturers, the correct selection starts with required flow rate, displacement per revolution, differential pressure, fluid viscosity, and available installation space.
Suofu offers precision micro magnetic gear pumps with nominal displacements from 0.1 to 26 mL/rev and published flow ranges up to 65 L/min, providing options for precision dispensing, fluid sampling, spraying, cooling circulation, and industrial fluid transfer.
The first step in selecting a micro gear pump is defining how much liquid the system needs to transfer.
Three operating conditions should be established:
Minimum Flow: The lowest stable flow required during operation.
Normal Flow: The flow used during most of the equipment's operating cycle.
Maximum Flow: The highest required flow during peak demand.
For example, a precision dispensing system may require 0.3 L/min during normal operation and 0.8 L/min at maximum output.
A pump rated for 1.5 L/min could be considered, but only after confirming that it can maintain the required flow at the actual operating pressure and fluid viscosity.
Selecting a pump with the highest available flow capacity does not necessarily improve accuracy or efficiency.
Micro gear pumps are positive displacement pumps. Their theoretical flow rate is determined by the volume displaced per revolution and the rotational speed.
The theoretical flow calculation is:
Q = V × N / 1000
Where:
Q = Theoretical flow rate (L/min)
V = Pump displacement (mL/rev)
N = Rotational speed (rpm)
For example, a pump with a displacement of 0.6 mL/rev operating at 1,000 rpm produces a theoretical flow of:
Q = 0.6 × 1000 / 1000 = 0.6 L/min
However, actual delivered flow may be lower because of internal leakage, differential pressure, and fluid properties.
A more practical calculation includes volumetric efficiency:
Qactual = (V × N × ηv) / 1000
Where ηv represents the volumetric efficiency under the operating conditions.
This is why engineers should evaluate the manufacturer's flow-pressure performance curves rather than relying exclusively on theoretical displacement.
Suofu's NP Series provides several pump configurations covering different flow requirements.
Pump Series | Nominal Displacement | Published Flow Range | Typical Selection Direction |
|---|---|---|---|
NP20 | 0.1 mL/rev | 0–1.5 L/min | Very compact, low-flow applications |
NP42 | 0.2–0.7 mL/rev | 0–2.2 L/min | Precision dispensing and small-volume transfer |
NP51 | 1.0–1.9 mL/rev | 0–6.0 L/min | Small and medium fluid circulation |
NP60 | 2.4–3.5 mL/rev | 0–10.5 L/min | Medium-flow equipment |
NP98 | 4–17 mL/rev | 0–55 L/min | Higher-flow circulation and transfer |
NP106 | 26 mL/rev | 0–65 L/min | Larger flow requirements |
These figures represent published product-family ranges, not guaranteed flow at every pressure, viscosity, or motor speed.
Selection principle: Choose a displacement that provides the required flow within a practical operating-speed range while maintaining sufficient pressure capability and control stability.
A micro gear pump does not generate a fixed operating pressure independently of the connected system.
Differential pressure is determined by the resistance of downstream and upstream components, including:
Tubing and pipework
Filters and valves
Spray nozzles
Heat exchangers
Flow meters
Fluid viscosity
Height differences and process equipment
For example, a dispensing system may require only 0.5 L/min but operate against a substantial pressure drop caused by a narrow nozzle.
In this situation, choosing a pump solely because it exceeds 0.5 L/min under free-flow conditions may lead to insufficient actual delivery.
The selected model must maintain the required flow at the specified differential pressure.
Also distinguish between maximum differential pressure and pump body pressure rating. A high allowable housing pressure does not mean the pump can generate an equivalent pressure difference.
Viscosity directly affects internal leakage, suction performance, motor torque, and the practical operating-speed range.
For low-viscosity liquids, internal leakage can become more significant as differential pressure increases.
For higher-viscosity liquids, internal leakage may decrease, but mechanical resistance, suction losses, and motor load can increase.
Therefore, engineers should provide viscosity data at the actual operating temperature rather than specifying only the liquid name.
For example:
Fluid Condition | Selection Consideration |
|---|---|
Low-Viscosity Liquid | Verify internal leakage and flow at pressure |
Medium-Viscosity Liquid | Balance motor speed and required torque |
High-Viscosity Liquid | Evaluate suction resistance and reduce speed where necessary |
Temperature-Varying Fluid | Check viscosity across the complete operating range |
Material compatibility should also be checked for the pump body, gears, shafts, bearings, and other wetted components.
An oversized pump may appear to offer a convenient safety margin, but it can create additional operating problems.
If a pump with excessive displacement must run at a very low speed to deliver the required flow, the system may experience reduced control resolution, less stable delivery, or unsuitable motor operating conditions.
Conversely, an undersized pump may need to operate continuously near its maximum speed, reducing available adjustment capacity and potentially increasing wear.
For precision fluid delivery, the preferred pump should operate within a stable and controllable speed range under normal conditions.
A reasonable engineering approach is to select a pump based on its normal operating point and then verify the minimum and maximum conditions.
Motor selection is closely related to displacement and flow control.
Suofu offers multiple motor configurations, including brushless DC, stepper, servo, and AC motor options.
Brushless DC Motors: Suitable for adjustable-speed operation in compact OEM systems.
Stepper Motors: Useful where controlled rotational movement and repeatable dispensing cycles are required.
Servo Motors: Suitable for applications requiring closed-loop speed or position control.
AC Motors: Applicable to continuous fluid-transfer systems with compatible drive arrangements.
Motor torque must be sufficient for the required differential pressure and fluid viscosity.
For low-flow precision applications, smooth speed regulation and feedback control may be more important than maximum rotational speed.
Even when hydraulic performance is suitable, mechanical integration can determine whether a pump is practical for an OEM product.
Important dimensions and interfaces include the pump body envelope, mounting arrangement, inlet and outlet port sizes, motor length, and electrical connection.
Inlet design is equally important.
A narrow or excessively long suction line can cause excessive pressure loss and poor filling of the gear chambers, especially when handling viscous liquids.
Suofu recommends short, straight inlet piping and suitable filtration for liquids containing particles.
The inlet pressure and available suction head should be checked to prevent cavitation or unstable flow.
As a manufacturer specializing in precision micro magnetic gear pumps, Suofu provides different NP Series displacements and motor configurations for OEM fluid handling systems.
Our engineering team supports selection based on operating flow, pressure, viscosity, temperature, and mechanical integration requirements.
For projects where standard configurations are unsuitable, our OEM/ODM micro gear pump solutions support customization of:
Pump displacement and operating range
Motor type and speed control
Pump body and wetted materials
Inlet and outlet connections
Mounting dimensions and installation interfaces
Electrical and system integration requirements
By evaluating the complete fluid system, we help equipment manufacturers identify suitable pump configurations instead of selecting solely by nominal flow capacity.
Start by determining the required flow rate, differential pressure, fluid viscosity, and intended motor speed. Use pump displacement to estimate theoretical flow, then verify actual performance using the manufacturer's curves.
Not necessarily. An oversized pump operating at an unsuitable low speed may provide less effective flow adjustment than a smaller pump working within its recommended speed range.
Potentially, but the operating speed, motor torque, suction conditions, and actual flow may change. Compatibility and performance should be confirmed for each liquid.
Displacement is the theoretical volume transferred during one pump revolution, typically expressed in mL/rev. Flow rate describes the volume delivered per unit time, commonly expressed in mL/min or L/min.
Yes. Suofu supports OEM/ODM development involving pump displacement, motor selection, materials, port connections, mounting arrangements, and operating parameters.
The right micro gear pump is not necessarily the smallest model or the one with the highest flow rating.
Reliable selection depends on matching pump displacement, motor speed, differential pressure, and liquid properties to the actual operating conditions.
For equipment manufacturers, evaluating these parameters early in the design process can reduce integration problems, improve flow control, and avoid unnecessary equipment costs.
Need help selecting a micro gear pump?
Contact Suofu Pump with your required minimum and maximum flow, operating pressure, liquid viscosity, temperature range, motor preferences, and available installation space. Our engineers can help evaluate a suitable NP Series configuration and discuss OEM customization options.
