Low temperature breaks pumps in ways that are easy to miss until the pump is running. The same machine that handles an ambient fluid without complaint can seize, leak, or shatter a seal once the medium drops to −40°C, and the trouble only deepens toward cryogenic temperatures. Carbon steel turns brittle, elastomer seals lose their grip and start to weep, parts shrink at different rates and open up clearances, and a cold liquid near its boiling point flashes to gas at the inlet. A pump chosen from a room-temperature catalogue rarely survives any of this. This page covers how Aulank pumps handle low-temperature and cryogenic fluids, down to liquid nitrogen at −196°C, and which pump architecture fits which duty.
Why Low Temperature Defeats Standard Pumps
Cold does not attack a pump in one way; it attacks several at once. The failures below tend to arrive together:
● Metals turn brittle. Carbon and low-alloy steels pass through a ductile-to-brittle transition as they cool, losing the toughness that keeps them from cracking. A casing or shaft that is fine at ambient can fracture under cold-start stress.
● Elastomer seals go hard and leak. Near their glass-transition temperature, O-rings and lip seals stiffen, stop rebounding, and lose contact stress — so a joint that sealed at room temperature seeps or whistles in the cold, and a dynamic shaft seal is the first thing to fail.
● Differential contraction opens clearances. Metals and elastomers shrink at different rates on cooldown. Squeeze falls out of spec, running clearances change, and seal faces can lift — the colder the duty, the larger the movement.
● Lubricants thicken or freeze. Conventional bearing greases and oils stiffen at low temperature, raising start-up friction and starving bearings exactly when the load is highest.
● The fluid flashes at the inlet. A cryogen or cold solvent sitting near its boiling point vaporises as soon as inlet pressure dips, so the pump sees two-phase flow, loses prime, and cavitates unless suction and insulation are handled deliberately.
● Ice and frost form. Atmospheric moisture freezes on cold surfaces, and water trapped in the wrong place becomes ice that jams moving parts.
The Aulank Approach: Sealless, Elastomer-Free, Contraction-Tolerant
Most of the failures above trace back to two components: the dynamic mechanical seal and the materials around it. Aulank's low-temperature pumps remove the first and choose the second for the cold:
● No dynamic seal to embrittle. A sealless magnetic-drive or canned design transmits torque through a static containment shell, so there is no rotating elastomer or spring-loaded seal face to harden, lose squeeze, and leak. This is the single biggest reliability gain at low temperature, and the same principle behind our leak-proof pump solutions.
● Austenitic stainless wetted parts. 300-series stainless steel keeps its toughness at cryogenic temperature rather than passing through a ductile-to-brittle transition, so wetted casings and internals stay sound in the cold. Where a duty calls for it, nickel-copper and other cold-rated alloys are available.
● Process-lubricated bearings. Silicon-carbide bearings are lubricated by the pumped fluid itself, not by grease or oil that would freeze. The cold medium does the cooling and the lubricating, so there is no lubricant to solidify.
● Wide-temperature magnets and contraction-tolerant clearances. The magnet system and the running clearances are specified for the cold operating point and the cooldown transient, so torque transmission and fits hold as the pump contracts.
● Insulation and suction design for two-phase fluids. For cryogens and near-boiling media, the hydraulic path, insulation, and inlet are configured to limit heat ingress and keep the liquid below its vapour point at the inlet, which protects prime and suppresses flashing.
One honest boundary: the deepest cryogenic duties — liquid hydrogen at −253°C, liquid helium, and large air-separation or LNG trains — are a specialised field of their own. Aulank's range reaches liquid nitrogen at −196°C, which covers the great majority of industrial low-temperature and cryogenic process duties.
Pump Types and Working Principles
AYDH Magnetic Liquid Nitrogen Pump (cryogenic, to −196°C)
The AYDH magnetic liquid nitrogen pump is the cryogenic member of the range, built for liquid nitrogen and comparable cryogens. It is fully sealless, with cold-rated wetted materials, process-lubricated bearings, and a hydraulic and insulation design that handles the two-phase behaviour of a cryogen near its boiling point. It is the pump for transferring, circulating, or dosing liquid nitrogen without a shaft seal to embrittle. Selection detail for this duty is in our cryogenic liquid nitrogen pump selection guide.
MDW / MDH / MDS Stainless Vortex Magnetic Pumps (low-temperature, high head)
For low-temperature circulation that needs more head than flow — cold coolant loops, brine and refrigerant circuits, low-temperature solvent transfer — the stainless vortex (regenerative-turbine) magnetic pumps fit well. The MDW, MDH, and MDS are sealless, stainless-wetted, and generate high head at modest flow, the opposite of a centrifugal pump's profile. They are configured for the cold operating temperature of the specific duty. The whole Magnetic Vortex Pump Series shares this regenerative-turbine principle.
MDC-K Magnetic Gear Pump (cold viscous and metered, to −60°C)
When the cold fluid is viscous, or the duty needs a steady metered volume rather than a head-flow curve, the MDC-K magnetic gear pump is the better fit. As a sealless positive-displacement pump it delivers a fixed volume per revolution regardless of how the viscosity climbs as the fluid cools, and its temperature range covers cold service down to roughly −60°C. It is the low-temperature choice for thick or precisely dosed media.
Where Low-Temperature Pumping Solves a Real Problem
The same set of cold-duty problems recurs across very different industries:
● Liquid nitrogen handling. Transfer, top-up, and dosing of LN2 for freezing, inerting, cold traps, and sample storage — duties where a leaking seal is both a process loss and a safety hazard.
● Semiconductor low-temperature coolants. Circulating fluorinated heat-transfer fluids and low-temperature brines for process cooling and test chambers, where leakage of an expensive engineered fluid is unacceptable. Aulank vortex magnetic pumps are used in exactly this service.
● Battery and component cold testing. The cold side of thermal-cycling rigs, where the coolant viscosity swings sharply as temperature drops and a sealless pump avoids the repeated seal failures that thermal cycling causes.
● Low-temperature chemical reactions. Circulating and dosing reagents and solvents held well below ambient for selective or exothermic chemistry, where temperature and zero leakage both matter.
● Refrigerant, glycol, and brine loops. Secondary-coolant circulation in cold storage, food freezing, and process chilling, where a clean sealless pump runs maintenance-light.
Matching the Pump to the Temperature
As a starting point, the duty and temperature point to the architecture:
| Duty | Fluid / temperature | Key requirement | Recommended pump |
| Liquid nitrogen transfer, circulation, dosing | LN2, −196°C | Elastomer-free, contraction-tolerant, two-phase capable | AYDH magnetic LN2 pump |
| Low-temperature coolant circulation (high head) | Fluorinated fluids, brine, refrigerant | Sealless, high head at low flow, leak-free | MDH / MDW / MDS vortex magnetic |
| Cold cooling-loop circulation | Glycol, refrigerant, cold process water | Clean, leak-free circulation | MDW vortex magnetic |
| Cold viscous or metered transfer | Cold oils and media, to −60°C | Volumetric output across viscosity, leak-free | MDC-K magnetic gear |
The table is a first cut. The actual choice depends on the full picture below, and the lowest temperature the pump will ever see — including cold-start and excursions, not just the steady operating point.
Key Selection Considerations
When you specify a low-temperature pump, the details that decide success are:
● The minimum temperature, including transients. Give the coldest temperature the pump will see, not the average — cold-start and process excursions set the material and clearance requirements.
● The fluid and its vapour pressure. Whether the medium sits near its boiling point at the operating temperature decides how hard the suction and insulation have to work to prevent flashing.
● NPSH at the cold operating point. Vapour pressure and suction layout at temperature determine the available NPSH; cryogens and near-boiling fluids leave little margin, so the suction side has to be designed, not assumed.
● Materials for the medium and the cold. Wetted materials have to suit both the chemistry and the temperature — austenitic stainless as standard, cold-rated alloys where the duty calls for them.
● Insulation and two-phase handling. For cryogenic and near-boiling duties, confirm how heat ingress is limited and how the pump handles any vapour at the inlet.
● Flow and head, or metered volume. A circulation duty is defined by flow and head; a dosing or viscous duty is defined by the volume per unit time and the viscosity range across temperature.
Get a Low-Temperature Pump Configuration for Your Process
Tell us the fluid, the minimum and operating temperatures, the flow and head or the metered volume, and the suction layout, and our engineering team will configure a sealless low-temperature or cryogenic pump for the duty — from liquid nitrogen at −196°C to cold coolant and brine loops. For the high-temperature end of the range, see our high-temperature pump solutions.
Talk to our team: Contact Aulank | WhatsApp: +86 13773157367 | Email: info@aulankpump.com
Related reading: cryogenic liquid nitrogen pump selection guide · magnetic drive pump selection guide