What plastic process equipment is about
Plastic process equipment covers vessels, tanks, exhaust air scrubbers, ventilation ducts, pipe components and entire plant modules made from thermoplastics. Parts are cut from sheets and semi-finished products, formed and welded. They are used mainly where metal would corrode: in chemicals, electroplating and surface treatment, water and wastewater treatment, and utilities and waste management.
The advantage does not come from the material alone but from precise adaptation to the application. A well-designed custom build fits the medium, temperature, space and connections. A poorly designed one is simply more expensive than a standard product.
When plastic makes sense and when it does not
| Makes sense if | Less sensible if | Why |
|---|---|---|
| Standard products do not fit properly | A standard product already meets the requirements | Then a custom solution adds no value |
| Chemical resistance and corrosion protection are central | Very high temperatures or strength are required | Then a metallic material is often more suitable |
| Space, connections or standards are special | The task stays simple and standardised | Then a custom design is needlessly complex |
A typical example is a surface treatment company that must replace a pickling bath in a cramped hall. A standard tank fits neither the recess nor the existing connections, and a stainless steel tank would be attacked by the medium. This is where plastic equipment shows its strengths: the shape follows the room, the nozzles sit where the existing pipes end, and the material is matched to the medium.
The picture is different for a simple free-standing water storage tank. Proven series products exist for this, and a custom build would mainly add planning effort and cost.
Just because plastic is technically possible does not make it the best choice.
Materials and alternatives compared
Equipment construction mainly uses polypropylene (PP), polyethylene (PE), PVC and, for more demanding cases, PVDF. They differ in chemical resistance, permissible temperature, stiffness and price. Which material fits can only be judged on the basis of the specific medium, its concentration and the temperature range. Manufacturers' resistance charts are a starting point but do not replace design by a specialist.
| Option | Strength | Limit |
|---|---|---|
| Plastic process equipment | High chemical resistance, good adaptability, low weight | Less suitable for very high temperatures or mechanical loads |
| Standard product | Quickly available, proven, often cheaper | Often does not fit special processes or installation situations exactly |
| Metallic solution | Strong under temperature, pressure and mechanical stress | Not always the best or cheapest choice with corrosive media |
Process and required documents
The more complete the information at the start, the fewer loops in design and manufacturing. Have the following ready for your first enquiry:
- Medium with concentration, any solids and cleaning agents
- Operating and peak temperatures
- Pressure or vacuum, fill levels, loads from agitators or internals
- Dimensions, available space, access for installation and maintenance
- Interfaces and connections to existing plant
- Applicable standards and regulations, plus documentation requirements
- Existing plans, drawings or photos
- Analyse requirements and classify them technically
- Select the material and define the design
- Approve the design, manufacture and test
- Deliver, install or integrate into the existing plant
Clarify regulations early
In Switzerland, tanks for liquids hazardous to water are subject to water protection requirements, and pressure equipment to its own safety rules. Clarify early with the manufacturer and the competent authority which certificates are needed.
Costs and service life
There are no catalogue prices for custom builds. Costs result from size, material, wall thickness, design effort, testing and documentation requirements and overall complexity. The biggest cost driver is rarely a single item but the sum of these factors.
The purchase price is not the only criterion. Service life, corrosion resistance, maintenance effort, operational safety and follow-up costs matter just as much. In normal operation, maintaining well-designed plastic equipment usually comes down to visual checks and routine inspections. A metal tank that must be refurbished every few years because of corrosion can end up more expensive despite a lower initial price.
- Obtain quotes with an identical specification so they are comparable
- Ask about warranty, test reports and welding certificates
- Include spare parts, accessibility and inspection intervals in the calculation