4" Front Port Pressure Vessels
8 models in this family. Representative models: Serie 4" V4i 21, Permeat assembly, Feed assembly.
International brand dossier
Knappe Pressure Vessels
Knappe Composites manufactures compact FRP membrane housings, RO pressure vessels, Xtype skids, and stainless components for RO and NF systems.Its The brand emphasizes more than 40 years of expertise, in-house manufacturing, and EU PED / ASME Section X design, making it relevant where vessel compactness and code expectations shape skid design.
Knappe Pressure Vessels's position in RO/NF membranes and related equipment is defined by product families such as 4" Front Port Pressure Vessels, 8" Side Port Pressure Vessels, 8" Front Port Pressure Vessels and Extra information.
The portfolio is best understood inside brackish water, seawater desalination, ultrapure water, process separation, reuse, degassing, and membrane system packaging, where engineers compare the technology route, family boundaries, and duty fit before narrowing to individual models.Representative series on this page include Serie 4" V4i 21, Permeat assembly and Feed assembly.Engineers should compare element size, salt rejection, permeate flow, pressure rating, fouling resistance, connection type, and vessel fit.
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Indexed models
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Product families
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Subgroups
Product range and selection
How to choose Knappe Pressure Vessels
This section answers two questions: which main product families Knappe offers, and which parameters to compare before choosing a specific model.
Step 1: Choose a product family by application
The main families shown on this page are 4" Front Port Pressure Vessels, 8" Side Port Pressure Vessels, 8" Front Port Pressure Vessels, and Extra information. Start with the treatment objective, equipment format, and operating duty, then use the model index below to compare exact specifications.
Step 2: Confirm the model by key parameters
After choosing a product family, compare pressure rating, element count, port layout, and code requirement. Replacement projects should also verify installation or loading conditions, interfaces, and compatibility with the existing system; new projects should consider operating practice, maintenance, and spare-parts or consumables availability.
Product family overview
4 product familys on this page.
8" Side Port Pressure Vessels
9 models in this family. Representative models: Serie 8" 3Ss 21, Permeat assembly, Feed assembly.
8" Front Port Pressure Vessels
11 models in this family. Representative models: Serie 8"V2s 21, Permeat assembly, Feed assembly.
Extra information
6 models in this family. Representative models: Knappe Catalog 8" Pressure Vessels, Knappe AnyParts, Knappe AnyRack Single.
Quick Model Index
Fast lookup for 34 indexed products
The table is intentionally compact: use it to scan model names, product families, and source links quickly. Open the profile cards below when you want richer context.
4" Front Port Pressure Vessels
8 indexed models
| Model | Application | Sources |
|---|---|---|
| Serie 4" V4i 21 | This is a 4-inch front-entry reverse osmosis membrane pressure vessel from Knappe's V4i series. | |
| Permeat assembly | This is a Knappe endplate assembly for 4-inch RO membrane vessels, designed for the permeate/brine side application. It supports various union options rated up to 300 PSI. | |
| Feed assembly | This is a Knappe Pressure Vessels feed assembly, model 14EP4-C, designed as an endplate for RO membrane housings. | |
| Serie 4" V4i 31 | The Knappe Pressure Vessels Serie 4" V4i 31 is a front-entry reverse osmosis membrane pressure vessel. | |
| Serie 4" V4i 42 | The Knappe Pressure Vessels Serie 4" V4i 42 is a front-entry reverse osmosis membrane housing designed for one to six elements. | |
| Serie 4" V3 70 | This is a Knappe Composites 4-inch front-entry RO membrane pressure vessel designed for reverse osmosis systems. | |
| Permeat assembly | This is a Permeat assembly from Knappe Pressure Vessels, designed for use with RO membrane systems. | |
| Feed assembly | This is a Knappe feed assembly designed for RO membrane pressure vessels. |
8" Side Port Pressure Vessels
9 indexed models
| Model | Application | Sources |
|---|---|---|
| Serie 8" 3Ss 21 | The Knappe Serie 8" 3Ss 21 is an 8-inch diameter, multi-element brackish water reverse osmosis pressure vessel. | |
| Permeat assembly | This is an Endplate ASSY Sideport for the Knappe Series S3s RO membrane pressure vessels. | |
| Feed assembly | Feed assembly is a membrane housing or pressure vessel for RO/NF membrane systems, best compared by port format, element count, and installation envelope. | |
| Serie 8" 3Ss 31 | The Knappe Series 8" 3Ss 31 are 8-inch diameter sideport brackishwater reverse osmosis membrane pressure vessels designed for 60-inch elements. | |
| Serie 8" 3p 42 | The Knappe Pressure Vessels Serie 8" 3p 42 is an 8-inch diameter brackish water RO membrane pressure vessel rated for 600 PSI. It features a FRP shell, PVC liner. | |
| Permeat assembly | This is an Endplate Assembly for Knappe Pressure Vessels' Series S3p, designed for RO membrane applications. | |
| Feed assembly | This is an endplate assembly designed as a sideport for Knappe Pressure Vessels Series S3p, with a closed permeate. | |
| Serie 8" SXp 70 | The Knappe Pressure Vessels Serie 8" SXp 70 is an 8-inch diameter FRP and PVC reverse osmosis membrane pressure vessel designed for seawater applications. | |
| Feed assembly | This is an Endplate Assembly Sideport for Knappe Composites Series S3p, designed with a permeate closed configuration. |
8" Front Port Pressure Vessels
11 indexed models
| Model | Application | Sources |
|---|---|---|
| Serie 8"V2s 21 | This is a Knappe Pressure Vessels Series 8"V2s 21 front-entry membrane housing designed for brackish water applications. | |
| Permeat assembly | This is a front port endplate assembly designed for RO membrane pressure vessels by Knappe Composites. | |
| Feed assembly | This is a feed assembly for RO membrane pressure vessels, including various EPDM O-rings. It is an O-rings and endplate assembly with additional listed components. | |
| Serie 8"V2s 31 | The Knappe Pressure Vessels Serie 8"V2s 31 is an 8-inch front-entry FRP pressure vessel designed for brackish water applications and can house multiple 40-inch membrane... | |
| Serie 8"V2s 42 | The Knappe Pressure Vessels Serie 8"V2s 42 is an 8-inch front-entry reverse osmosis membrane pressure vessel. It is constructed with an FRP shell, PVC liner. | |
| Permeat assembly | This permeate assembly is the Endplate ASSY Frontport model 18EP-M-BW-V2s from Knappe Pressure Vessels, designed for RO membrane systems. | |
| Feed assembly | This feed assembly is designed for RO membrane pressure vessels. It includes multiple EPDM O-rings for sealing. | |
| Serie 8"V2 70 | This is a Knappe Series 8" V2 70 front-entry RO membrane pressure vessel designed for reverse osmosis applications. | |
| Permeat assembly | This is a Knappe Permeat assembly, the front endplate for RO membrane pressure vessels. It is rated for 1000/1200 PSI and includes EPDM O-rings for sealing. | |
| Feed assembly | This Knappe Pressure Vessels feed assembly is designed for RO membrane systems. It features EPDM O-rings and is rated for pressures up to 1200 PSI. | |
| Serie 8"V2 84 | The Knappe Serie 8"V2 84 is an 8-inch, front-entry FRP seawater RO membrane pressure vessel. |
Extra information
6 indexed models
| Model | Application | Sources |
|---|---|---|
| Knappe Catalog 8" Pressure Vessels | Knappe Catalog 8" Pressure Vessels are designed as RO membrane housings featuring the AnyClic self-sealing endplate and AnyDistance shimming system. | |
| Knappe AnyParts | These Knappe AnyParts are permeate port adapters designed for RO membrane housings. Available in various materials like PVC, PA66, PP, and SS 316L. | |
| Knappe AnyRack Single | The Knappe AnyRack Single is an RO membrane pressure vessel designed for water treatment applications. | |
| Knappe AnyRack Double | The Knappe AnyRack Double is a pressure vessel designed for RO membrane systems. | |
| Knappe Assembly & Operating Instructions 4 inch | This is a 4-inch front port composite vessel designed for RO/UF applications, built to ASME X code for brackish or seawater desalination. It features food-grade PVC, PPE. | |
| Knappe Assembly & Operating Instructions 8 inch | This composite vessel is designed for reverse osmosis, nanofiltration, and ultrafiltration applications, housing any make of 8-inch spiral-wound membrane elements. |
AI-ready Product Profiles
Product cards for screening and future AI matching
These cards are designed as reusable product profiles: the same format can later appear in AI search results, shortlist views, and assisted product matching.
4" Front Port Pressure Vessels
8 profile cards
Pressure Vessels
Product profile
Serie 4" V4i 21
This is a 4-inch front-entry reverse osmosis membrane pressure vessel from Knappe's V4i series.
Pressure Vessels
Product profile
Permeat assembly
This is a Knappe endplate assembly for 4-inch RO membrane vessels, designed for the permeate/brine side application. It supports various union options rated up to 300 PSI.
Pressure Vessels
Product profile
Feed assembly
This is a Knappe Pressure Vessels feed assembly, model 14EP4-C, designed as an endplate for RO membrane housings.
Pressure Vessels
Product profile
Serie 4" V4i 31
The Knappe Pressure Vessels Serie 4" V4i 31 is a front-entry reverse osmosis membrane pressure vessel.
Pressure Vessels
Product profile
Serie 4" V4i 42
The Knappe Pressure Vessels Serie 4" V4i 42 is a front-entry reverse osmosis membrane housing designed for one to six elements.
Pressure Vessels
Product profile
Serie 4" V3 70
This is a Knappe Composites 4-inch front-entry RO membrane pressure vessel designed for reverse osmosis systems.
Show remaining 4" Front Port Pressure Vessels profiles (2)
Pressure Vessels
Product profile
Permeat assembly
This is a Permeat assembly from Knappe Pressure Vessels, designed for use with RO membrane systems.
Pressure Vessels
Product profile
Feed assembly
This is a Knappe feed assembly designed for RO membrane pressure vessels.
8" Side Port Pressure Vessels
9 profile cards
Pressure Vessels
Product profile
Serie 8" 3Ss 21
The Knappe Serie 8" 3Ss 21 is an 8-inch diameter, multi-element brackish water reverse osmosis pressure vessel.
Pressure Vessels
Product profile
Permeat assembly
This is an Endplate ASSY Sideport for the Knappe Series S3s RO membrane pressure vessels.
Pressure Vessels
Product profile
Feed assembly
Feed assembly is a membrane housing or pressure vessel for RO/NF membrane systems, best compared by port format, element count, and installation envelope.
Pressure Vessels
Product profile
Serie 8" 3Ss 31
The Knappe Series 8" 3Ss 31 are 8-inch diameter sideport brackishwater reverse osmosis membrane pressure vessels designed for 60-inch elements.
Pressure Vessels
Product profile
Serie 8" 3p 42
The Knappe Pressure Vessels Serie 8" 3p 42 is an 8-inch diameter brackish water RO membrane pressure vessel rated for 600 PSI. It features a FRP shell, PVC liner.
Pressure Vessels
Product profile
Permeat assembly
This is an Endplate Assembly for Knappe Pressure Vessels' Series S3p, designed for RO membrane applications.
Show remaining 8" Side Port Pressure Vessels profiles (3)
Pressure Vessels
Product profile
Feed assembly
This is an endplate assembly designed as a sideport for Knappe Pressure Vessels Series S3p, with a closed permeate.
Pressure Vessels
Product profile
Serie 8" SXp 70
The Knappe Pressure Vessels Serie 8" SXp 70 is an 8-inch diameter FRP and PVC reverse osmosis membrane pressure vessel designed for seawater applications.
Pressure Vessels
Product profile
Feed assembly
This is an Endplate Assembly Sideport for Knappe Composites Series S3p, designed with a permeate closed configuration.
8" Front Port Pressure Vessels
11 profile cards
Pressure Vessels
Product profile
Serie 8"V2s 21
This is a Knappe Pressure Vessels Series 8"V2s 21 front-entry membrane housing designed for brackish water applications.
Pressure Vessels
Product profile
Permeat assembly
This is a front port endplate assembly designed for RO membrane pressure vessels by Knappe Composites.
Pressure Vessels
Product profile
Feed assembly
This is a feed assembly for RO membrane pressure vessels, including various EPDM O-rings. It is an O-rings and endplate assembly with additional listed components.
Pressure Vessels
Product profile
Serie 8"V2s 31
The Knappe Pressure Vessels Serie 8"V2s 31 is an 8-inch front-entry FRP pressure vessel designed for brackish water applications and can house multiple 40-inch membrane...
Pressure Vessels
Product profile
Serie 8"V2s 42
The Knappe Pressure Vessels Serie 8"V2s 42 is an 8-inch front-entry reverse osmosis membrane pressure vessel. It is constructed with an FRP shell, PVC liner.
Pressure Vessels
Product profile
Permeat assembly
This permeate assembly is the Endplate ASSY Frontport model 18EP-M-BW-V2s from Knappe Pressure Vessels, designed for RO membrane systems.
Show remaining 8" Front Port Pressure Vessels profiles (5)
Pressure Vessels
Product profile
Feed assembly
This feed assembly is designed for RO membrane pressure vessels. It includes multiple EPDM O-rings for sealing.
Pressure Vessels
Product profile
Serie 8"V2 70
This is a Knappe Series 8" V2 70 front-entry RO membrane pressure vessel designed for reverse osmosis applications.
Pressure Vessels
Product profile
Permeat assembly
This is a Knappe Permeat assembly, the front endplate for RO membrane pressure vessels. It is rated for 1000/1200 PSI and includes EPDM O-rings for sealing.
Pressure Vessels
Product profile
Feed assembly
This Knappe Pressure Vessels feed assembly is designed for RO membrane systems. It features EPDM O-rings and is rated for pressures up to 1200 PSI.
Pressure Vessels
Product profile
Serie 8"V2 84
The Knappe Serie 8"V2 84 is an 8-inch, front-entry FRP seawater RO membrane pressure vessel.
Extra information
6 profile cards
Pressure Vessels
Product profile
Knappe Catalog 8" Pressure Vessels
Knappe Catalog 8" Pressure Vessels are designed as RO membrane housings featuring the AnyClic self-sealing endplate and AnyDistance shimming system.
Pressure Vessels
Product profile
Knappe AnyParts
These Knappe AnyParts are permeate port adapters designed for RO membrane housings. Available in various materials like PVC, PA66, PP, and SS 316L.
Pressure Vessels
Product profile
Knappe AnyRack Single
The Knappe AnyRack Single is an RO membrane pressure vessel designed for water treatment applications.
Pressure Vessels
Product profile
Knappe AnyRack Double
The Knappe AnyRack Double is a pressure vessel designed for RO membrane systems.
Pressure Vessels
Product profile
Knappe Assembly & Operating Instructions 4 inch
This is a 4-inch front port composite vessel designed for RO/UF applications, built to ASME X code for brackish or seawater desalination. It features food-grade PVC, PPE.
Pressure Vessels
Product profile
Knappe Assembly & Operating Instructions 8 inch
This composite vessel is designed for reverse osmosis, nanofiltration, and ultrafiltration applications, housing any make of 8-inch spiral-wound membrane elements.