1 Industry Background & Market Pain Points

The market demand for micro magnetic gear pumps is not generated in a vacuum; it is driven jointly by the precision, miniaturisation and greening trends of downstream industries. Understanding these trends is the starting point for understanding the product value.

1.1 The Mega-Trend of Precision Fluid Delivery

In recent years, multiple high-tech industries are undergoing a systemic upgrade of fluid-control requirements. The core features can be summarised as the "Five Highs + One Small":

• High precision — semiconductor photoresist coating, developer supply, CMP slurry delivery require flow accuracy of ±1 % or better, while strictly limiting metal-ion leaching.

• High micro-volume — analytical instruments (HPLC, ICP-MS) reagent delivery, medical dialysate proportioning, new-energy electrolyte additive injection require flow rates as low as μL/min with long-term stability and zero drift.

• High pressure — liquid-cooling circulation, chemical micro-reactor feeding, hydraulic lubrication injection require outlet pressure from several bar to tens of bar; the micro pump must withstand high pressure difference in a limited volume.

• High corrosion / high hazard — photoresist, developer, strong acid / alkali solvents, electrolytes etc. are highly corrosive or toxic; shaft-seal leakage causes not only medium loss but also safety hazards and environmental pollution.

• High reliability — semiconductor fabs, data centres and medical equipment require 7×24-hour continuous operation; life requirements range from thousands to tens of thousands of hours, and maintenance windows are limited.

• Small volume — under the equipment-integration trend, pump installation space is severely constrained; traditional standard-size magnetic pumps often cannot fit.

These six trends overlap to form a clear technical-demand space: high-precision, leak-free, long-life micro-fluid metering delivery in a coMPact envelope. The micro magnetic gear pump is a technical route developed precisely to satisfy this demand space.

Table 1-1 Demand-matrix interpretation: how the "Five Highs + One Small" map to pump performance

1.2 Structural Shortcomings of Traditional Pump Technologies

Before the maturity of micro magnetic gear pumps, common micro / small pump products on the market each have advantages, but all share structural shortcomings under precision duty:

Table 1-2 CoMParison of traditional micro / small pumps

1.3 Pain-Point Analysis Specific to Micro Duty

Beyond the common problems of traditional pumps, the micro chemical duty itself brings a series of specific technical challenges that directly determine whether the product can run reliably in real scenarios:

Table 1-3 Pain points specific to micro chemical duty

These pain points are not isolated; they often stack. For example, semiconductor chemical delivery simultaneously involves micro-flow, high corrosion, heavy-metal contamination, and continuous run. This requires the micro magnetic gear pump to be systematically optimised across material, structure, magnetic circuit and bearing — not simply a downsized standard pump.

2 Technical Principles & Structural Anatomy

This chapter starts from the operating principle and disassembles the core technical architecture of the micro magnetic gear pump layer by layer, analysing the key technical challenges that miniaturisation brings and the corresponding engineering solutions.

2.1 Operating Principle of Micro Gear Pumps

The micro gear pump is a positive-displacement rotary pump. Its operating principle is based on the change of tooth-space volume during gear meshing:

• Suction stage: on the side where the gears disengage (suction side), the tooth-space volume increases, creating local negative pressure; the medium is drawn into the tooth space under pressure difference.

• Transport stage: the medium is sealed between the tooth space and the pump inner wall, and is carried by the gear rotation to the discharge side.

• Discharge stage: on the side where the gears re-engage (discharge side), the tooth-space volume decreases and the medium is squeezed out, forming the output flow.

Each gear rotation completes one suction-discharge cycle per tooth space. Because the tooth-space volume is a fixed geometric parameter, under ideal conditions the output flow is proportional to the speed — this naturally gives the gear pump the characteristic of a metering pump: precise flow control is achieved by precise speed control.

Micro gear pumps usually use external-mesh spur or helical gears. Spur gears are simpler to machine but show clear trapped-oil at high speed; helical gears give smoother meshing transition, helping to lower pulsation and noise, but require higher machining accuracy. Some high-end products use modified tooth profiles to optimise meshing characteristics in the micro-scale.

2.2 Magnetic-Drive Principle

Magnetic drive is the core technology that distinguishes micro magnetic gear pumps from ordinary gear pumps. The basic principle is to use magnetic coupling to achieve power transmission, replacing dynamic sealing with static sealing and eliminating leakage paths from the structure:

Table 2-1 Components and function of the magnetic drive

During operation, the motor drives the outer magnetic ring; the alternating N/S poles generate a rotating magnetic field, which penetrates the non-magnetic containment can and drives the inner ring synchronously, which in turn drives the gear shaft. Because the containment can physically isolates the medium chamber from the outside world, there is no rotating shaft penetrating the pump body — this is the essence of the "shaftless" structure.

2.3 Technical Challenges of Miniaturisation

Scaling a magnetic gear pump down to micro size is not a proportional shrink. Several physical quantities do not scale proportionally after the size shrink, bringing a series of unique engineering challenges:

2.3.1 Ultra-small Gear Machining

Micro gear-pump gear modules may be as low as 0.3 – 0.8 mm, with tooth width only a few mm. Such small gears demand extremely high machining accuracy:

• tooth-profile error must be controlled at μm level, otherwise tooth-space volume inconsistency directly causes flow pulsation and metering-accuracy drop;

• surface roughness affects friction, wear and medium shear — Ra < 0.4 μm is required;

• radial clearance (gear to housing) and axial clearance (gear face to side plate) must be precisely controlled in 5 – 15 μm — too large → internal leakage and efficiency drop; too small → seizure risk;

• non-metal gears (PEEK, ceramic) require very different processes from metal gears — special moulding or precision grinding is needed.

2.3.2 Magnetic-Circuit Design

After miniaturisation the magnet-ring volume drops markedly, and the available magnetic-coupling force (torque) decreases with it. Achieving sufficient torque transmission within the limited volume is the core challenge of magnetic-circuit design:

• pole count, pole-arc coefficient and air-gap thickness must be optimally matched for torque density;

• thicker can increases the air gap and reduces torque transmission efficiency, but thinner can compromises pressure bearing — must be precisely balanced;

• high-T operation reduces NdFeB magnetic performance (coercivity temperature coefficient ≈ −0.6 %/°C); temperature margin must be reserved at design;

• controlled-slip protection: in overload, controlled slip rather than catastrophic failure; detection means must also be set to identify slipping in time.

2.3.3 Containment-Can Selection & Eddy-Current Heating

The containment can is a key component of magnetic transmission. When the outer ring rotates, if the can is conductive, the alternating magnetic field induces eddy current in the can wall and produces Joule heat — "eddy loss". In a micro pump, because the heat-dissipation area is small, eddy heating is more significant:

• metal cans (316L, Hastelloy) have relatively large eddy loss; temperature rise may affect medium stability and magnet performance;

• non-metal cans (PEEK, CFRP) eliminate eddy loss, but pressure bearing and wall-thickness uniformity control are challenges;

• thermo-magnetic coupled analysis should be done at design to evaluate steady-state T rise; add heat-dissipation structures or select low-loss materials when necessary.

2.3.4 Bearing Matching & Lubrication

Micro magnetic gear pumps typically use medium self-lubrication — the pumped medium itself acts as lubricant. Two challenges arise:

• low-viscosity media (water, solvent) have weak lubricating-film load capacity; at high speed, boundary or dry friction occurs, accelerating bearing wear;

• if micro-particles or crystallisation products exist in the medium, they act as abrasives and accelerate bearing and gear wear.

Common bearing materials include SiC, alumina (Al₂O₃), PEEK / CFRP composites — selection depends on medium properties, speed and load. Some products allow short-time dry running (seconds to tens of seconds) via self-lubricating materials, but prolonged dry running still causes overheat damage.

2.3.5 Thermal-Management Challenge after Miniaturisation

Among the four challenges above (gear machining, magnetic-circuit design, can material, bearing lubrication), there is one cross-cutting hidden factor — heat. After miniaturisation the heat-dissipation area shrinks sharply and multiple internal heat sources stack, making thermal management the key reliability bottleneck. There are three main heat sources in a micro pump:

• Friction heat: gear–bearing friction — micro pumps have small clearance and high linear speed, so friction power density exceeds large pumps;

• Eddy heat: eddy loss in the metal containment can — alternating field in the conductive can wall, directly converted to Joule heat;

• Medium-conducted heat: the pumped medium itself brings heat — when conveying high-T medium, heat is conducted through the pump body into the magnet and bearing areas.

Table 2-2 Stacked effect of three heat sources on key pump components

In actual design thermal management requires systematic thinking: use a non-metal containment can to eliminate the largest heat source (eddy); use high-T magnets to widen temperature margin; optimise bearing PV value to lower friction heat; add fins or forced-air cooling on the housing when necessary. For high-T medium duty, also evaluate the margin between medium temperature and each component's temperature limit to ensure no thermal failure under the worst-case combined duty.

2.4 Breakdown of Core Components

Although small, micro magnetic gear pumps have very high component-level technical content. Each key component is broken down by function below:

Table 2-3 Breakdown of core components

2.5 Material System & Selection Logic

Material selection is the core means to adapt the micro magnetic gear pump to different medium duties. Different materials trade off corrosion resistance, mechanical strength, wear resistance, temperature range, and processability; system-level matching is required for a specific medium:

Table 2-4 Material-coMParison matrix

Material selection must follow the "full medium-contact-chain matching" principle — every part in contact with the medium (gear, bearing, pump inner wall, seal, containment can inner surface etc.) must be coMPatible with the medium. Any incorrect material choice can cause corrosion-product contamination, component failure, or seal leakage.

3 Performance Indicators & Reliability Validation

A technical white paper must be supported by data and test methods, not just concepts. This chapter establishes a data-driven performance-validation system for micro magnetic gear pumps from three layers: core performance dimensions, key test items, and common failure modes.

3.1 Core Performance Dimensions

Evaluating the performance of a micro magnetic gear pump cannot rely only on flow and pressure. A complete performance profile should include the following dimensions:

Table 3-1 Core performance dimensions of micro magnetic gear pumps

Note that the parameters above are not independent — metering accuracy drifts with viscosity; pressure rise increases internal leakage and reduces effective flow; too low a speed increases the pulsation share. Therefore performance evaluation must be done under clear medium conditions (viscosity, temperature, density) and system conditions (back pressure, piping resistance).

3.2 Key Test Items

3.2.1 Leak-Free Verification Test

Purpose: verify static-seal integrity of the magnetic-drive structure; ensure no leakage across the full pressure-difference range.

• Pressure-hold test: block outlet; pressurise inlet to 1.3 – 1.5× rated; hold 10 – 30 min; observe pressure drop & external leakage.

• Helium leak test: helium mass-spectrometer leak detection on critical seal surfaces; leak rate < 1×10⁻⁶ Pa·m³/s (per application).

• Cyclic pressure test: 0 – rated cycle more than 1 000 times; verify seal fatigue reliability.

3.2.2 Long-Life Endurance Test

Purpose: evaluate pump life & performance decay under continuous duty.

• Run continuously at rated duty (flow, pressure, medium); record flow-decay curve, noise change, current fluctuation.

• Typical test duration: 2 000 – 5 000 h (depending on application); some critical applications require 10 000 h+.

• After test, dismantle and inspect gear wear, bearing clearance change, magnet demag etc.

3.2.3 Medium-CoMPatibility Test

Purpose: verify chemical stability and long-term coMPatibility of pump materials in the target medium.

• Immersion test: immerse material coupons in the target medium for a specified time (72 h / 168 h / 30 d); detect weight change, dimensional change, mechanical-property change.

• Circulation test: cycle the target medium under real duty; monitor medium-purity change, particle increase, material leaching.

• Key media to test: photoresist (PGMEA etc.), NMP, IPA, electrolyte, strong acid / alkali, DI water.

3.2.4 Environmental-Adaptability Test

Table 3-2 Environmental-adaptability test matrix

3.2.5 Dry-Running Tolerance Test

Purpose: evaluate short-time dry-running capability. Magnetic gear pumps in principle do not allow dry running, but real use inevitably includes transient dry-run scenarios such as start-up venting and medium switching.

• Run at rated speed without medium; record bearing T rise, torque change, abnormal sound.

• Typical dry-run tolerance: 10 – 60 s (depending on bearing material & speed); beyond this time must stop immediately.

• Self-lubricating bearings (e.g. carbon-fibre PEEK) have better dry-run tolerance than pure ceramic bearings.

3.2.6 Accelerated Life Test (ALT)

For high-reliability industries such as semiconductor and aerospace, conventional rated-duty long-life tests lasting thousands of hours cannot meet product-iteration verification timelines. Accelerated Life Testing (ALT) applies combined stresses above rated conditions to trigger potential failure modes in a much shorter time and extrapolate equivalent life at rated duty.

Table 3-3 ALT acceleration dimensions

Key ALT principle: acceleration stress must not introduce failure mechanisms absent at rated duty ("acceleration validity" check). E.g. temperature acceleration must not exceed the magnet Curie T causing irreversible demag — that failure does not occur at normal duty and would invalidate the life extrapolation. A typical ALT flow: identify critical failure modes → choose acceleration stresses → design the experiment matrix → run & record failure times → fit accelerated-life curve with a statistical model (Weibull etc.) → extrapolate rated-duty life.

3.3 Common Failure-Mode Analysis & Optimisation

Understanding failure modes is the prerequisite for reliable selection and use. The most common failure modes of micro magnetic gear pumps in real applications, with their root causes and optimisation directions:

Table 3-4 Common failure modes & root causes

4 Downstream Industry Application Scenarios

This chapter breaks down the typical application scenarios of micro magnetic gear pumps by industry. For each scenario we start from duty requirements, analyse the pain points of the existing solution, explain the value of the micro magnetic gear-pump solution, and provide typical parameter reference.

4.1 Semiconductor Industry

4.1.1 Duty Requirements

• Photoresist coating: flow accuracy ±1 % or better; very low pulsation; no metal-ion contamination (Fe, Na, K below ppb level).

• Developer / stripper supply: strongly alkaline or acidic media; needs corrosion resistance and leak-free.

• CMP slurry delivery: contains nano-abrasive particles; very high wear-resistance requirement.

• Wet-cleaning chemicals: multiple strong-acid blending; frequent medium switching.

4.1.2 Pain Points of Existing Solutions

Traditional mechanical-seal gear pumps have shaft-seal micro-leakage that causes chemical vapours to corrode the equipment environment; metal gear and bearing wear particles may contaminate the wafer. Peristaltic pump pulsation and tube-particle shedding are not suitable for precision coating. Diaphragm pump flow pulsation cannot meet precision-ratio requirements.

4.1.3 Solution

Micro magnetic gear pump adopts PEEK or ceramic gear + non-metal containment can, achieving zero metal leaching across all medium-contact surfaces; static-seal structure ensures zero leakage; positive-displacement metering ensures ±1 % flow accuracy; stepper-motor drive enables pulse-level flow control.

Table 4-1 Semiconductor-industry parameter reference

4.1.4 Selection Risk Alerts

• Bubble risk: if the medium contains bubbles (e.g. insufficiently degassed photoresist), install an online degasser before the pump inlet, otherwise bubbles cause flow surge and coating defects.

• Abrasive wear: CMP slurry contains nano-hard particles; long-term operation accelerates gear / bearing wear. SiC ceramic gear + SiC bearing recommended, with shortened maintenance intervals.

• Temperature sensitivity: photoresist is temperature-sensitive (high T may trigger polymerisation). Evaluate pump-chamber T rise effect on the medium; consider non-metal can to eliminate eddy heat.

4.2 Analytical Instruments & Medical Equipment

4.2.1 Duty Requirements

• HPLC: mobile phase delivery needs extremely low pulsation, high repeatability; flow from μL/min to mL/min.

• Biochemical analyser: reagent micro-dispensing; rapid response, precise metering, no cross-contamination.

• Medical dialysis / infusion equipment: extremely high safety requirements; medium is saline, dialysate etc. biocoMPatible liquid.

4.2.2 Pain Points

HPLC traditionally uses piston pumps — accurate yet structurally complex, high maintenance, and pulsation must be suppressed by a damper. Biochemical analysers often use syringe pumps — dispensing speed limited and no continuous supply. Peristaltic pump accuracy & pulsation do not meet analytical-grade requirements.

4.2.3 Solution

The micro magnetic gear pump can serve as a precision metering or transfer pump in analytical instruments, paired with micro-step stepper motors for smooth low-flow output. In medical devices, the leak-free structure meets biosafety requirements; PEEK / ceramic materials meet FDA & USP Class VI biocoMPatibility standards.

Table 4-2 Analytical-instrument / medical parameter reference

4.2.4 Selection Risk Alerts

• Pulsation control: analytical-grade use is extremely sensitive to pulsation. Gear-pump inherent tooth-frequency pulsation must be paired with a damper or helical-gear design; otherwise baseline noise rises and analytical precision drops.

• Cross-contamination: biochemical analysers switch reagents frequently; residual medium in the pump chamber may cause cross-contamination. Recommend small chamber volume + standardised cleaning (clean volume ≥ 5× chamber volume).

• Safety redundancy: medical-device pump failure may pose patient-safety risk. Configure flow / pressure sensors for fault detection & alarm to avoid abnormal delivery.

4.3 New-Energy Industry

4.3.1 Duty Requirements

• Alkaline water electrolysis: KOH solution circulation; highly corrosive; explosion-proof required.

• Lithium-battery manufacturing: electrolyte (containing LiPF₆) precise micro-injection; extremely low moisture, corrosion-resistant.

• Fuel cell: coolant circulation; electrical insulation (low conductivity); no metal contamination.

• Liquid cooling: coolant (e.g. ethylene-glycol water) circulation; long life; low maintenance.

4.3.2 Pain Points

Ordinary stainless pumps cause metal-ion leaching affecting electrolyte quality; strong corrosive KOH ages seals quickly; explosion-proof environment with shaft-sealed pumps has safety hazards; fuel-cell coolant requires ultra-low conductivity; metal-part electrochemical corrosion contaminates coolant.

4.3.3 Solution

Hastelloy or all-non-metal (PEEK / ceramic) flow path for strong-corrosion coMPatibility; leak-free magnetic drive naturally adapts to explosion-proof; all-non-metal flow path keeps coolant conductivity low, protecting the fuel-cell stack. Li-battery electrolyte injection uses stepper motors for precise volume control, avoiding over- or under-injection.

Table 4-3 New-energy-industry parameter reference

4.3.4 Selection Risk Alerts

• Moisture control: Li-battery electrolyte is extremely moisture-sensitive (< 20 ppm); residual moisture in the line and pump chamber must be completely removed. Recommend vacuum bake + dry-N₂ purge before first use, with online moisture monitor in the line.

• Crystallisation risk: KOH electrolyte may crystallise at low T; after stop, flush pump chamber thoroughly with DI water, otherwise crystallised material may seize gears and cause magnetic slip / motor overload on restart.

• Conductivity control: fuel-cell coolant requires ultra-low conductivity (< 5 μS/cm); any metal part (incl. stainless fittings) can raise conductivity through electrochemical corrosion. Ensure full flow path (incl. fittings) is non-metal.

4.4 Fine Chemicals & Micro-Reaction

4.4.1 Duty Requirements

• Micro-reactor feeding: precise ratio of multiple feeds; ratio accuracy directly affects product yield and purity.

• Corrosive chemical media: strong acid / alkali, organic solvent, oxidiser; strict material coMPatibility.

• Lab to pilot scale-up: need wide adjustable flow range to switch between process scales.

4.4.2 Pain Points

Lab syringe pumps are accurate but have limited range, cannot run continuously. Pilot-scale diaphragm pumps have large pulsation, ratio accuracy is hard to guarantee. Corrosive media is a harsh test for ordinary pump seals and materials, leading to frequent maintenance.

4.4.3 Solution

The micro magnetic gear pump maintains stable accuracy over a wide flow range, suitable for multi-channel synchronous control to achieve exact ratios. Hastelloy or PTFE-liner options adapt to strong-corrosive media. Leak-free structure provides intrinsic safety for toxic, volatile chemicals. With a servo motor it can deliver programmable variable-flow, satisfying micro-reaction dynamic adjustment.

Table 4-4 Fine-chemical / micro-reaction parameter reference

4.4.4 Selection Risk Alerts

• Multi-channel synchronisation: micro-reactor multi-channel feed requires strict synchronisation of each channel. Use a single controller to drive multiple pumps to avoid independent-control synchronisation error. Also evaluate back-pressure differences between channels for ratio accuracy.

• Reaction risk: strongly exothermic reaction media may react abnormally in the pump chamber (polymerisation, decomposition); evaluate residence time and T rise in the chamber; lower speed if necessary to shorten residence.

• Medium switching: when switching media in chemical duty, verify the new medium is coMPatible with pump materials, especially seals — FKM is not resistant to some ketones and amines; switch to FFKM or PTFE.

4.5 Printing & Ink Industry

4.5.1 Duty Requirements

• UV-ink supply: high viscosity (200 – 1 000 cP); stable delivery to print head; pressure must overcome head back-pressure.

• Solvent ink delivery: contains volatile organic solvent; anti-evaporation, anti-leakage.

• Digital printing ink supply: flow accuracy directly affects colour consistency; low-pulsation stable supply.

4.5.2 Pain Points

Ordinary gear-pump shaft-seal leakage causes solvent volatilisation, ink loss and workshop safety hazard. Diaphragm pump pulsation causes uneven ink supply, affecting print quality. Peristaltic pump tube ages quickly in organic solvent, replacement cost high and causes production interruption.

4.5.3 Solution

Micro magnetic gear pump can stably convey medium-high-viscosity ink; leak-free structure prevents solvent volatilisation. PEEK gear + FKM / FFKM seal for ink medium. Stepper-motor drive enables precise ink-supply control; with a pressure sensor it forms closed-loop supply, ensuring stable print-head inlet pressure.

Table 4-5 Printing / ink-industry parameter reference

4.5.4 Selection Risk Alerts

• Viscosity temperature-sensitivity: high-viscosity ink (500 cP) gets more viscous at low T, possibly causing insufficient start torque and magnetic slip. Recommend ink insulation line or choose larger torque motor + high-T magnet.

• Pigment particles: UV ink may contain pigment agglomerates; long-term operation wears gear tooth surfaces. Install a 50 μm inlet filter; periodically inspect gear wear.

• System sealing: solvent ink has strong volatility; pipe fittings and valves may also leak. Evaluate sealing of the entire ink-supply system, not just the pump body.

4.6 Aerospace & Laboratory Equipment

4.6.1 Duty Requirements

• Aerospace: small fluid-circulation systems (e.g. thermal-management loops); extreme lightweight, high reliability, vibration / shock resistance.

• Laboratory: analytical-instrument supply, reactor feed, sampling systems; precise metering, flexible medium switching, easy maintenance.

4.6.2 Pain Points

Aerospace is extremely weight / volume sensitive; standard magnetic pumps are too heavy and large. Laboratory equipment handles many media types with frequent switching; traditional pump dead-legs and seal coMPatibility issues stand out.

4.6.3 Solution

Micro magnetic gear pump's coMPact volume and lightweight design suit aerospace integration; all-non-metal solution meets special-medium contamination-free requirements. In laboratory use, small pump-chamber volume eases quick cleaning and medium switching; modular design supports fast head replacement.

Table 4-6 Aerospace / lab-equipment parameter reference

4.6.4 Selection Risk Alerts

• Vibration / shock: in aerospace duty the vibration & shock load is large; verify housing structural and magnetic-coupling anti-vibration design — especially inner ring connection to gear shaft — to avoid vibration-induced ring falling-off or misalignment.

• Extreme temperature: aerospace extreme temperature range (−55 °C to +85 °C or wider) causes material CTE mismatch and gear clearance change; use low-CTE materials (ceramic, Invar) and wide-T clearance compensation.

• Cleaning dead-legs: in lab multi-medium switching, pump-chamber dead-legs are high-risk for residual and cross-contamination. Choose a design with no dead-legs and establish standardised cleaning SOPs.

4.7 Liquid Cooling & Data Centres

4.7.1 Duty Requirements

• Data-centre liquid cooling: server cold-plate coolant circulation; low conductivity (anti-short-circuit); long life (limited maintenance window); coMPact installation.

• Immersion cooling: large-flow coolant circulation; the pump must adapt to special coolant (fluorinated fluid, synthetic oil).

• Energy-storage liquid cooling: battery thermal-management coolant circulation; wide T range; vibration-resistant; high reliability.

4.7.2 Pain Points

Data-centre liquid cooling requires strict coolant conductivity (< 10 μS/cm); ordinary stainless pumps' metal-ion leaching raises conductivity and short-circuit risk. Traditional magnetic pumps are too bulky for server-level integration. Limited maintenance window requires very long maintenance-free life.

4.7.3 Solution

All-non-metal flow path (PEEK body + ceramic gear / bearing + non-metal can) ensures coolant conductivity does not rise, satisfying data-centre safety. Miniaturised design fits 1U / 2U server internal installation. Long-life bearing & efficient magnetic circuit deliver > 10 000 h maintenance-free run. With BLDC motor for low-power, low-noise operation.

Table 4-7 Liquid-cooling / data-centre parameter reference

4.7.4 Selection Risk Alerts

• Conductivity full-link: data-centre cooling systems require extremely strict conductivity (< 10 μS/cm); all system components (incl. fittings, valves) must be non-metal; any stainless fitting can be a metal-leaching source.

• Space constraint: server-internal space is very tight; pump + motor + fitting total size must be strictly within design envelope, with inlet / outlet orientation matching piping routing to avoid pipe-bend extra resistance.

• Noise control: data centre requires very low noise (< 45 dB); high-speed pump operation may generate audible noise. Choose BLDC low-speed operation, and evaluate vibration-transmission noise path to the rack.

• Bubble management: coolant may contain micro-bubbles (from line dissolved-gas release); bubbles compressed-expanded in pump chamber cause noise & flow fluctuation. Recommend gas-liquid separator or vent valve before inlet.

5 Engineering Selection & Practical Guide

This chapter is the practical section for engineers. From selection parameters to installation & use, it provides directly actionable engineering reference. Selection is not "pick a pump" — it is a system-matching process covering medium characteristics, duty conditions, system piping, and drive control.

5.1 Key Selection Factors

The selection of a micro magnetic gear pump should follow the decision procedure below, confirming key parameters layer by layer:

Table 5-1 Key selection factors & suggestions

5.1.1 NPSH (Net Positive Suction Head) Calculation & Selection Requirements

NPSH is divided into two values:

• NPSHa (available head): the actual effective head above medium vapor pressure at the pump inlet, determined by supply head, inlet line resistance, and medium vapor pressure. NPSHa = (Pₐ/ρg) ± Hs − Hf − Pv/ρg (Pₐ = atmospheric, Hₛ = supply height, Hf = inlet line resistance loss, Pᵥ = saturation vapor pressure of medium at duty T).

• NPSHr (required head): the minimum inlet head required by the pump itself, determined by the pump's internal geometry, provided by the manufacturer. NPSHr of a micro gear pump is typically 0.5 – 2 m (depending on speed and tooth profile).

Selection criterion: NPSHa ≥ NPSHr × 1.3 (safety factor). If NPSHa is insufficient, take measures:

1. Raise supply level (high-level supply tank, recommend 0.5 – 1 m above pump inlet);

2. Increase inlet pipe size and shorten inlet line to lower Hf;

3. Lower pump speed to lower NPSHr demand;

4. Lower medium T to lower Pᵥ (especially important for volatile media);

5. Add a booster supply pump before the inlet if necessary.

Note: low-viscosity media (water, solvent) + high speed is the cavitation-prone combination; focus on NPSH margin calculation.

5.1.2 Selection Margin Principle

Avoid "exactly fitting" selection. Leaving 20 % – 30 % margin in both flow and pressure is the basic engineering principle. Two reasons: (1) actual duty is usually worse than the nominal condition (line aging, filter clogging → back-P rises); (2) margin lowers the pump's operating load and extends service life. But margin should not be excessive (> 50 %), otherwise the operating point deviates from the efficient range and accuracy and stability suffer.

5.2 Motor-Drive Selection

The motor is the "brain" of the micro magnetic gear pump, directly affecting flow-control accuracy, response speed, and operating stability. The three common drive methods have different applicable duties:

Table 5-2 Motor-drive selection coMParison

Flow-calibration key points: theoretical gear-pump flow Q = n × V₀ × ηᵥ (n = speed, V₀ = displacement, ηᵥ = volumetric efficiency). Actual flow is affected by medium viscosity, temperature, back pressure, speed etc. Therefore real-medium calibration must be done at factory or before use — establish a speed–flow correspondence table or fitting curve in the target medium & duty, as the control reference.

5.3 Piping-Matching Suggestions

The pump's performance depends not only on the pump itself but also heavily on the piping-system matching. Key suggestions:

Table 5-3 Piping-matching best practices

5.4 Common Misuses

The following misuses are frequently observed in real applications. Most early pump failures are not product-design issues but the result of improper use:

Table 5-4 Common misuses & consequences

5.5 Maintenance Key Points

Micro magnetic gear pumps require relatively low maintenance, but the following maintenance items must not be overlooked:

• Daily inspection: regularly check inlet-filter ΔP; clean or replace the filter element when ΔP rises.

• Performance monitoring: monitor operating current / power; current rise may indicate bearing wear or medium viscosity change.

• Abnormal-noise check: listen for pump operating noise change; abnormal noise (e.g. sharp whine, periodic knock) is usually a precursor to failure.

• Periodic calibration: periodically calibrate flow–speed correspondence, compensating flow decay due to wear.

• Medium switching: thoroughly clean pump chamber with coMPatible solvent before switching media, avoiding inter-media reaction or crystallisation.

• Stop maintenance: for long-term stop, drain pump chamber, clean with coMPatible solvent, dry-store, prevent crystallisation & corrosion.

• Periodic replacement: replace seals at recommended interval (typically 1 – 2 years, depending on medium & T), don't wait for leak.

6 Safety, Compliance & Certification

In industrial applications, product safety & compliance is the entry barrier to the market. The leak-free structure of micro magnetic gear pumps has inherent advantages, but the following dimensions still need attention:

6.1 Safety Value of Leak-Free Design

The static-seal structure of magnetic drive upgrades "leakage prevention" from probabilistic control to structural guarantee. In the following scenarios this safety value is particularly prominent:

Table 6-1 Safety-value map of leak-free design by scenario

6.2 Material Compliance

Table 6-2 Compliance standard matrix

6.3 Explosion-Proof Adaptation

The Ex-proof advantage of the magnetic-drive structure is that the pump body has no dynamic-seal friction face and no rotating shaft penetration, so there is no risk of releasing flammable medium through seal leakage and no ignition source from seal friction. Combined with Ex-proof motor, Ex-proof cable gland and Ex-proof controller, system-level Ex-proof certification can be achieved.

Common Ex-proof grades & applicable zones:

• Flameproof type: Ex d IIB T4 — applicable to Zone 1 / 2, IIB gases (e.g. ethylene, xylene), surface T ≤ 135 °C.

• Flameproof type (IIC): Ex d IIC T4 — applicable to Zone 1 / 2, IIC gases (e.g. hydrogen, acetylene), highest Ex-proof requirement.

• Increased-safety type: Ex e IIB T4 — applicable to Zone 1, increased-safety design, prevents spark by raising safety margin.

7 Industry Trends & Outlook

7.1 Market Trends

The core trends driving growth of the micro magnetic gear-pump market:

• Acceleration of domestic semiconductor-equipment substitution; supporting-demand growth for wet-process equipment; wafer-fab capacity expansion drives chemical-delivery-pump demand.

• AI compute explosion drives rapid penetration of data-centre liquid cooling; coolant-circulation-pump demand grows by orders of magnitude in cold plates and CDUs.

• New energy (Li-battery, hydrogen, energy storage) capacity expansion; electrolyte injection, coolant circulation, electrolyte circulation etc. are in strong demand.

• Analytical instruments trend toward portability & miniaturisation; sustained demand growth for micro precision pumps.

• Chemical micro-reaction technology moves from lab to industrialisation; precise multi-channel micro-feeding demand grows.

Overall, the precision fluid-control market where micro magnetic gear pumps reside is in a demand-side multi-industry-driven growth phase. Domestic market CAGR is expected to stay above 15 % over the next 5 years, where semiconductor and data-centre liquid cooling are the two fastest-growing segments.

7.2 Technology Development Directions

Table 7-1 Technology development directions

7.3 Domestic-Substitution Opportunity & Challenge

The core logic of domestic substitution is not "cheaper price" but "on the basis of sufficient quality, providing faster delivery, more flexible customisation, and more competitive total cost of ownership (TCO)". This requires domestic manufacturers to build competitiveness in precision-machining capability, material technology, test-verification system, application technical support etc. The following is analysed from three layers — current status, gap, opportunity:

Currently, the high-end micro magnetic gear-pump market is still dominated by imported brands, especially in semiconductor and analytical instruments, where domestic market share is low. But the window of substitution is opening:

Table 7-2 Domestic-substitution matrix

For a more direct view of the technology gap & catch-up progress between domestic and imported products, the following is an unnamed coMParison across key performance dimensions (data based on public technical information & industry research, for reference only):

Table 7-3 Performance coMParison: domestic vs imported

From the coMParison, domestic products still have gaps vs imported high-end in metering accuracy, life and smart integration, but have clear advantages in cost, delivery and customisation. The gap is narrowing fast — especially in mid-end applications (liquid cooling, printing ink, chemical micro-reaction), domestic products already have strong competitiveness and are gradually penetrating into high-end fields like semiconductor.

7.4 Differentiated Breakthrough Directions for Domestic Micro Magnetic Gear Pumps

Differentiated competition is the key strategy of domestic substitution. Three directions deserve focus:

• Duty customisation: for domestic customers' specific duties (high-viscosity media such as UV ink & photoresist, easy-crystallisation media such as some electrolytes), develop special tooth-profile design & clearance schemes, providing performance not covered by imported standard products.

• Solution integration: upgrade from "selling pump" to "providing fluid-delivery solution", including pump + motor + driver + sensor system integration, as well as selection consulting, on-site commissioning, maintenance training & full-life-cycle service.

• Cooperative bundling: targeting the localisation trend of downstream equipment (domestic semiconductor equipment, liquid-cooling CDU, analytical instruments), deeply cooperate with downstream equipment manufacturers, intervene in pump selection & customisation at the equipment design stage, forming cooperative-bundling relationship.

7.5 Product Limitations — What Duties Are Not Suitable

To remain technically objective, the following explicitly states duty scenarios where the micro magnetic gear pump is not suitable or must be used with caution:

Table 7-4 Unsuitable / caution-limit duty scenarios