Most cold storage companies in Vietnam import pressure vessels and install them. Tan Long manufactures them in its own factory. That difference is not a branding matter — it changes how a project is designed, and changes what the business receives at handover.
What pressure vessels a refrigeration system contains
- High pressure tank — stores liquid refrigerant for the system
- Liquid separator — stops liquid refrigerant returning to the compressor
- Oil separator — recovers lubricating oil carried over with the refrigerant vapour
- Intermediate tank — cools the compressed vapour between stages in a multi-stage compression system
- Shell-and-tube condenser — rejects heat for water-cooled systems
This group falls under the category with strict occupational safety requirements: inspection is mandatory before use and on a periodic basis thereafter.
Why made-to-order manufacturing matters
Off-the-shelf pressure vessels come with fixed volumes and specifications. When the equipment does not match the calculated heat load, there are only two options: choose equipment larger than needed — costly and space-consuming, or accept equipment that is smaller — the system fails to meet its design.
Made-to-order manufacturing allows the reverse: calculate the heat load first, then build equipment to exactly those specifications. Beyond volume, nozzle positions, installation orientation and overall dimensions can all be adjusted to suit the machine room layout.
The difference in documentation
This is the benefit least often mentioned but with the biggest downstream impact. The documentation accompanying a pressure vessel comprises the design drawing, the strength calculation, material certificates, welding records, non-destructive weld examination results, the pressure test report and the equipment data record.
When the equipment is made in-house, this documentation is created during production itself. When it is bought through an intermediary, the business has to trace it backwards — and if it has passed through several hands, the full set may be unobtainable. See what pressure vessel inspection documentation comprises.
The manufacturing process
- Design calculation based on working pressure, refrigerant type and the specific operating conditions of the project
- Material selection matched to the refrigerant — note that NH3 corrodes copper and copper alloys
- Fabrication and welding by certified welders, following an approved welding procedure
- Non-destructive examination of the welds
- Pressure testing at the workshop, with a report
- Surface finishing and fitting accessories: safety relief valve, pressure gauge, level sight glass
- Creating the equipment data record and the accompanying documentation set
What businesses should ask for
Whichever contractor you choose, this is the list to put in the contract:
- Design drawing and strength calculation at the design pressure
- Material certificates for the steel used
- Welding procedure and welder certificates
- Non-destructive weld examination results
- Workshop pressure test report
- Equipment data record — the document that follows the equipment through its whole life
- Clarity on whose scope the first inspection cost falls within
Requiring these from the contract stage is far cheaper than chasing them once the inspection body has arrived.
When made-to-order manufacturing is genuinely necessary
- Large-capacity systems, where the difference between correctly sized and approximately sized equipment is significant
- NH3 systems, because of their specific material and safety requirements
- Cramped machine rooms or projects with constraints on dimensions and installation orientation
- Projects needing complete documentation for GSP or HACCP assessment, or for export markets
- Replacing equipment in a running system, where it must match existing nozzle positions
For small systems, standard off-the-shelf equipment is usually more sensible on time and cost. Made-to-order manufacturing pays off when the problem carries real constraints.
Tan Long's capabilities
Tan Long manufactures pressure vessels for refrigeration systems at its own factory, serving both projects Tan Long installs and standalone orders. The equipment is built to the specifications calculated for each project, complete with technical documentation and the records needed for inspection.
Alongside this is command of all three refrigerant families — NH3, CO2 and Freon — so the equipment solution proposed follows the plant's problem rather than being limited to a familiar refrigerant. See also range of industrial refrigeration equipment.
Frequently asked questions about pressure vessel manufacturing
What pressure vessels does a refrigeration system contain?
High-pressure receivers, liquid separators, oil separators, intercoolers and condensers. This group falls under the category with strict occupational safety requirements: inspection is mandatory before use and on a periodic basis thereafter.
How does made-to-order differ from buying off-the-shelf equipment?
Off-the-shelf equipment has fixed specifications, so when it does not match the heat load you must either choose larger than needed or accept smaller. Made-to-order manufacturing allows the heat load to be calculated first and the equipment built to exactly those specifications, including nozzle positions and dimensions suited to the machine room.
Why does equipment documentation matter?
Because without documentation there can be no inspection, and without inspection the equipment may not be operated. When made in-house, the documentation is created during production itself; when bought through several intermediaries, the full set may not be traceable.
What documentation should be required in the contract?
The design drawing, the strength calculation, material certificates, the welding procedure and welder certificates, non-destructive weld examination results, the workshop pressure test report, the equipment data record, and clarity on the first inspection cost.
When should equipment be made to order?
Large-capacity systems, NH3 systems because of their specific material requirements, cramped machine rooms with dimensional constraints, projects needing complete documentation for assessment, or replacing equipment in a running system that must match existing nozzles.
Do small systems need custom manufacturing?
Usually not. For small systems, standard off-the-shelf equipment makes more sense on time and cost. Made-to-order manufacturing pays off when the problem carries real constraints on capacity, materials or space.
