Short answer: an RO pressure vessel is a pressurized housing that contains membrane elements, routes feed, permeate, and concentrate, and keeps the seals correctly positioned. A Codeline RO housing is not a water-storage tank, chemical tank, FRP media vessel, or pump pressure tank; each vessel type has a different duty, pressure rating, closure, and inspection requirement.
Updated 30 July 2026: membrane-housing functions, Codeline selection, closure safety, Indonesian safety regulation, and commissioning evidence were clarified.
In the industrial world, especially in water treatment, pressure vessels have a role that cannot be ignored.
A pressure vessel stores energy because the fluid is pressurized. On an RO skid, the shell, ports, saddles, straps, permeate ports, end closures, adapters, interconnectors, and seals must work as one assembly. A mismatch in series, pressure class, element count, port, or spare part can cause leakage, bypass, element damage, and a dangerous closure release.
Identify the vessel type before selecting:
| Component | Actual function | Main selection data | Not a substitute for |
|---|---|---|---|
| RO membrane pressure vessel | Contains RO/NF elements and separates feed/concentrate from permeate | Model, element diameter, element count, pressure rating, ports, closure, adapters, seals | Storage or media tank |
| FRP media pressure vessel | Contains filter media, softener resin, or demin resin under pressure | Diameter, height, pressure class, distributor, bed depth, freeboard, valve | RO membrane housing |
| Hydropneumatic pressure tank | Stores drawdown water and stabilizes pump cycling with an air cushion/bladder | Drawdown volume, pre-charge, cut-in/cut-out, materials | RO housing or raw-water tank |
| Atmospheric tank | Stores raw or treated water near atmospheric pressure | Usable volume, material, vent, drain, structure, sanitation | Pressurized process vessel |
| Special chemical vessel | Contains or reacts process fluid under a dedicated design | Chemistry, materials, pressure/temperature, design code, safeguards | Ordinary unpressurized dosing tank |
This page focuses on RO membrane housings, particularly Codeline. For filter and softener vessels, use the FRP vessel range; for pumped-water systems, use the pressure-tank guide.
Main Functions of Pressure Vessels in Water Treatment
- Contain elements at the correct pressure rating. The housing must match skid design pressure, temperature, service fluid, and transients. Never infer a model pressure rating from diameter or shell colour.
- Route the three RO streams. Feed passes through the element feed spacer, concentrate leaves the train, and permeate enters the product tube. Incorrect adapters or seals can mix feed into permeate without an external leak.
- Retain the elements and closure. Thrust components, retainers, bearing plates, locks, and end closures must follow the series manual. Parts from 40E, 40S, 80E, 80H, 80S, or 80U are not automatically interchangeable.
- Provide connections and mechanical support. Ports, saddles, straps, orientation, and element-removal clearance must fit the skid without unapproved pipe or clamp loads.
Codeline Selection Table for New Skids and Retrofits
| Data collected | New skid | Retrofit or spare part |
|---|---|---|
| Nameplate/model | Select series and pressure rating from process duty | Photograph the full nameplate; do not request only a “4040/8040 housing” |
| Membrane elements | Diameter, nominal length, elements per vessel, adapters and seals | Photograph the old element label, interconnectors, adapters, and element positions |
| Pressure and temperature | Operating, design, cleaning, startup/shutdown, and possible surge | Record actual conditions and investigate the old failure |
| Ports | Size, material, location, feed/concentrate/permeate duty, and flow direction | Measure ports and send photographs of both ends and pipe spools |
| Supports | Saddles, straps, support spacing, horizontal/vertical orientation, service space | Inspect shell, straps, saddles, misalignment, and existing pipe loads |
| Closure | Closure type, drawing, part number, tools, and series procedure | Identify every component; do not mix revisions without confirmation |
PT Watermart Perkasa supplies Codeline 4040 housings, 80E series, and 80S series for suitable applications. Send the nameplate, skid layout, pressure, elements, ports, and spare-part requirement so the quotation can be checked against the actual arrangement.
Closure and Safety Checklist before Opening a Housing
- Stop the pump in the approved shutdown sequence and prevent restart under the facility energy-isolation procedure.
- Isolate every pressure source, including feed, concentrate, permeate, cleaning loop, flush, and air where present.
- Drain and vent until instruments and field verification confirm zero pressure; gauge position alone is not sufficient evidence.
- Confirm that temperature, chemical residual, and retained fluid are safe for the work.
- Clean the area and use the correct series manual and closure drawing.
- Inspect the shell end, groove, locks, plate, ports, O-rings, adapters, seals, and any corrosion or damage.
- Use only spare parts identified for the model and revision.
- After assembly, repressurize gradually from a safe position while checking for leakage; never stand in the potential closure-release line.
Do not strike the shell, grind pressure-retaining parts, improvise a retainer, or open a pressurized closure. Structural repair and return-to-service decisions require competent assessment and manufacturer involvement for the specific case.
Benefits of Using High Quality Pressure Vessels
Quality is not proved by shell appearance. Benefits arise when the model is correct, documentation is available, installation avoids unapproved loads, and inspection is recorded:
| Required outcome | Evidence |
|---|---|
| Mechanical safety | Legible nameplate, suitable rating, working relief/isolation, complete closure, and documented inspection |
| Stable permeate quality | Correct adapters, interconnectors, O-rings, and brine seals without bypass |
| Controlled pressure drop | Correct element count, spacer, flow, staging, and system cleanliness |
| Traceable retrofit | Model, serial, drawing, part numbers, photographs, and replacement history |
| Safe, efficient service | Planned element-removal space, isolation valves, drains, vents, and closure access |
In Indonesia, facility owners should determine the duties applicable under Minister of Manpower Regulation No. 37 of 2016 on Occupational Safety for Pressure Vessels and Storage Tanks. The BPK database records that it remains in force with partial revocation under Minister of Manpower Regulation No. 11 of 2026. Classification, inspection, operator, and documentation decisions require competent parties; this article is not a legal determination.
Commissioning Record for One RO Train
| Evidence | Record |
|---|---|
| Identification | Model and serial of each vessel, train/stage position, element sequence, closures, adapters, seals |
| Installation | Saddles/straps, orientation, alignment, service space, ports, pipe support, drains, vents |
| Leak test | Test medium, staged pressure, hold points, inspected areas, results, and personnel |
| Operating baseline | Feed/permeate/concentrate flow and pressure, temperature, conductivity, recovery, pressure drop |
| Protection | Relief, high-pressure trip, low-suction trip, valve positions, and startup/shutdown interlocks |
| Handover | As-built drawing, series manual, exploded view, spare-parts list, photographs, and inspection schedule |
This baseline helps separate external leakage, internal bypass, membrane problems, and changing pretreatment. When permeate conductivity rises, check instruments, seals, adapters, and element position before declaring the membrane failed.
Conclusion
An RO pressure vessel contains membranes and process pressure; it is not general clean-water or chemical storage. Select Codeline by model, pressure rating, elements, ports, closure, and layout, then prove the installation with inspection and commissioning baselines.
For a technical review, send the nameplate, photographs of both ends, drawing, pressure, temperature, membrane model, element count, ports, and spare-part requirement through the Watermart contact page. Do not open or repair a housing until the system is isolated, depressurized, and verified safe.