Industrial Refrigeration
System Overview
Industrial Refrigeration — System Overview
Cold stores, food freezing, dairies, breweries and chemical plants use ammonia (R-717) pumped-recirculation systems and secondary glycol or brine circuits. Seals must contain toxic ammonia, resist icing at the atmospheric side, and use elastomers that stay flexible at sub-zero temperatures and are compatible with ammonia.
Primary Systems Covered:
- Ammonia pumped recirculation: liquid ammonia pumps feeding evaporators from a low-pressure receiver.
- Secondary coolants: propylene / ethylene glycol and calcium chloride brine circuits.
- Process chilling: chilled water and brine for food, beverage and chemical processes.
Which mechanical seal suits liquid ammonia pumps?
Liquid ammonia recirculation pumps are typically fitted with dual pressurised cartridge seals on API Plan 53A with a compatible refrigeration-oil barrier, silicon carbide vs. carbon faces and EPDM or chloroprene elastomers. FKM is not suitable for ammonia, and copper alloys must not be used in ammonia service.
Root-Cause Failure Analysis — Field Example
Symptom: Glycol chiller pump seal leaks; ice build-up on the gland.
├── Diagnostic Evidence Required:
│ ├── Is moisture from the air freezing on the atmospheric side of the faces?
│ ├── Are the O-rings hard and cracked (below their low-temperature limit)?
│ ├── Is there no quench to keep the atmospheric side dry?
└── Engineered Solution:
├── Add a Plan 62 quench with dry nitrogen or glycol to keep moisture away from the faces.
├── Change to low-temperature EPDM rated below the minimum fluid temperature.
├── Use SiC vs SiC faces.
Frequently Asked Questions
Why do seals ice up on sub-zero pumps?
Below 0 °C, moisture in the air condenses and freezes on the atmospheric side of the seal, jamming the faces and springs. A quench (Plan 62) with dry nitrogen or glycol keeps the area dry, or a dual seal with a non-freezing barrier removes the problem.
Which elastomers are compatible with ammonia?
EPDM and chloroprene are commonly used with ammonia. FKM is attacked by ammonia and should be avoided. Always check the low-temperature limit of the chosen compound.
Request a Seal Selection
Send your pump make and model, refrigerant or coolant, minimum and maximum temperature, pressure, shaft size and speed to info@gipfelengg.com or use our enquiry form. Related: food, dairy & beverage, chemical plants. Gipfel Engineering (ISO 9001:2015, NSIC-registered MSME, Mumbai) designs and manufactures mechanical seals, seal support systems and process pumps.
Equipment solutions: Compressors & Bearing Chambers · Overhung Pumps.
Pump Duty & Mechanical Seal Selection Matrix
Typical values for selection guidance only. Final selection is made against the pump data sheet; check elastomer low-temperature limits for each duty.
| Pump duty | Fluid | Typical temp. | Typical pressure (bar) | Seal arrangement | Faces / elastomer | API piping plan |
|---|---|---|---|---|---|---|
| Liquid Ammonia Recirculation | Liquid anhydrous ammonia (R-717) | −33 to −15°C | 1.0–4.5 | Dual pressurised cartridge, steel / stainless wetted parts (no copper alloys) | SiC vs antimony-free carbon / EPDM or chloroprene (FKM is unsuitable for ammonia) | API Plan 53A (compatible refrigeration-oil barrier) |
| Sub-Zero Glycol Chiller | Propylene / ethylene glycol solution | −35 to −15°C | 3.5–5.5 | Single balanced cartridge, low-temperature elastomers | SiC vs SiC / low-temperature EPDM | API Plan 11 + Plan 62 (dry nitrogen or glycol quench to prevent icing at the atmospheric side) |
| Calcium Chloride Brine | Calcium chloride brine | −40 to −20°C | 3.0–5.0 | Dual pressurised cartridge, super duplex wetted parts | SiC vs SiC / low-temperature EPDM | API Plan 53A (glycol-based barrier that will not freeze at duty temperature) |
Reviewed by Gipfel Engineering’s technical team.
Technical Information Disclaimer
The information on this page, including process descriptions, flow diagrams, operating ranges, seal arrangements, materials and piping plans, is general technical guidance for information only. Values shown are typical industry ranges, not guaranteed ratings or specifications of any Gipfel Engineering product. Each application differs. Seal selection, material compatibility, installation and operation must be verified by qualified personnel against the specific equipment data sheet, process conditions, applicable codes and the pump manufacturer’s instructions. A binding recommendation is given only in a written quotation or technical offer from Gipfel Engineering.
References to standards (such as API 682, ISO 21049, ISO 3069, FDA 21 CFR 177.2600 and NACE MR0175 / ISO 15156) describe common industry practice. They do not mean that any product is certified, qualified or approved to that standard unless this is confirmed in writing for a specific order. Third-party company and product names, including “equivalent to” references, are used for identification only and remain the trademarks of their owners. No affiliation, endorsement or OEM approval is implied.
Compliance with safety, hazardous-area, environmental and statutory requirements at the user’s site remains the responsibility of the plant owner or operator. To the extent permitted by law, Gipfel Engineering accepts no liability for loss or damage arising from reliance on this general information without a confirmed written recommendation. Content may change without notice.