RV High Purity Unloading Valve
Unloading (relief) valve protecting a regulator or panel leg from downstream over-pressure.
Built for ultra high purity specialty gas service, the RV belongs to the Cylinder & High Pressure Valves family covering isolation, switching and flow control.
RV High Purity Unloading Valve overview
The RV is a high purity specialty gas valve specified with the listed ports, a flow coefficient of a model-specific and a maximum working pressure of the rated. Unloading (relief) valve protecting a regulator or panel leg from downstream over-pressure. It is intended for the point in a high purity gas system where a clean, repeatable shut-off or switching function is needed without introducing a packed stem seal into the process stream.
A reinforced body, thickened seat area and high-strength stem are used to hold the pressure envelope at cylinder and tube-trailer ratings. Wetted parts remain low-inclusion stainless steel, and the primary seal is metal-to-metal so the valve can be helium leak tested at full working pressure. A short, smooth flow path and low internal volume make purge cycles fast, which matters when a line changes between reactive gases. Available end connections are vcr face seal, orbital butt weld or compression, so the same body can be used on face-sealed tool hook-ups, welded distribution headers or field-installed instrument lines.
Key features and design benefits
- the listed ports, Cv a model-specific — sized for high purity unloading valve flow duty without excess dead volume
- the rated maximum working pressure with a reinforced seat and helium-tested pressure envelope
- A reinforced body, thickened seat area and high-strength stem are used to hold the pressure envelope at cylinder and tube-trailer ratings.
- Electropolished wetted surfaces for fast dry-down and low moisture retention
- Manual or normally closed pneumatic actuation; pneumatic versions fail closed on loss of instrument air
- VCR, butt weld, compression or cylinder-standard end connections to match the installation
- Cleanroom assembly, double-bag packaging and per-valve leak records available
Technical specifications
| Body material | 316L stainless steel |
|---|---|
| Service | Specialty gas distribution |
| Leak test | Helium mass spectrometer |
| Model code | RV |
| Product family | Cylinder & High Pressure Valves |
| Sealing element | Reinforced metal seat, high-strength stem and metal primary seal |
| Wetted surface finish | Electropolished, typical Ra 0.25 um (10 uin) or better |
| Leak testing | Helium mass spectrometer, inboard and across seat; typical 1 x 10^-9 mbar l/s |
| Operating temperature | Typical -10 C to +80 C manual, -10 C to +65 C pneumatic |
| Actuation | Manual handwheel or normally closed pneumatic, 60-90 PSI instrument air |
| Cleanliness | Cleaned, dried and assembled for ultra high purity gas service |
| Packaging | Cleanroom double-bag, sealed for installation |
| Documentation | Material certificate, helium leak record, certificate of conformance |
Values above describe the standard configuration of model RV. Final materials, seat, actuation, test limits and certification are confirmed on the order-specific datasheet issued with your quote.
Model comparison within the Cylinder & High Pressure Valves family
Select the body by flow demand rather than by port size alone. The table below compares the RV with its sibling models on the three parameters that drive a gas system design: port size, flow coefficient and maximum working pressure.
Construction and wetted materials
A reinforced body, thickened seat area and high-strength stem are used to hold the pressure envelope at cylinder and tube-trailer ratings. Wetted parts remain low-inclusion stainless steel, and the primary seal is metal-to-metal so the valve can be helium leak tested at full working pressure. For the RV, the wetted path is machined from 316L VIM/VAR stainless steel with low inclusion and controlled sulfur content, then electropolished. A nickel-based diaphragm or seat alloy can be substituted where halide or hydride gases demand it.
| Component | Standard specification |
|---|---|
| Body | 316L VIM/VAR stainless steel bar stock |
| Wetted finish | Electropolished, typical Ra 0.25 um (10 uin) or better |
| Sealing element | Reinforced metal seat, high-strength stem and metal primary seal |
| Actuator | Manual handwheel or normally closed pneumatic piston, 60-90 PSI supply |
| Process connection | VCR face seal, orbital butt weld or compression |
End connections and port options
The RV is normally ordered with the listed ports. Connection choice affects both cleanliness and maintainability: VCR face seals give a repeatable metal-to-metal seal for tool hook-up, orbital butt welds suit permanent high purity headers, and compression fittings are used where a line must be assembled in the field.
| Parameter | Available option |
|---|---|
| Standard port | the listed |
| End connections | VCR face seal, orbital butt weld or compression |
| Seal standard | VCR face seal / orbital butt weld / compression / CGA or DISS for cylinder service |
| Actuation | Manual, or normally closed pneumatic with 60-90 PSI instrument air |
| Optional documentation | Material certificate, helium leak record, certificate of conformance |
Gas compatibility and typical applications
Model RV is selected for high pressure H2, N2, Ar, He, O2 and cylinder-grade specialty gas mixtures at source pressure. Always state concentration, temperature and any moisture or oxygen limit so the wetted alloy and seat can be confirmed before release.
- Semiconductor tool hook-up and gas cabinet isolation branches
- Valve manifold boxes, changeover panels and purge / vent legs
- High purity laboratory, analytical instrument and calibration gas lines
- Photovoltaic, MOCVD and hydrogen distribution systems
- Related application guides:
- Hydrogen & Fuel Cell High Pressure Valves
- Cylinder Cabinets & Bulk Gas Distribution
Installation, purging and handling
Install the RV with the flow direction and port orientation shown on the approved drawing. Keep the protective caps in place until the joint is made, tighten face-seal fittings to the specified torque, and purge with dry inert gas before introducing process gas. Because the internal volume is low, a short cyclic purge is normally enough to reach the required moisture level.
- Handle with clean gloves in a controlled area; do not open the double bag until installation
- Use orbital welding or certified face-seal glands on high purity headers
- Purge with dry N2 or Ar and verify moisture / oxygen upstream before process gas
- Helium leak check the assembled joint, then the inboard and across-seat envelope
- Record the serial number, leak result and gas service in the system dossier
Ordering and configuration
Quote the model code and the options below. Where a gas is corrosive or pyrophoric, include the concentration so the diaphragm or seat alloy can be matched to the service.
| Ordering parameter | Your selection |
|---|---|
| Base model | RV — RV High Purity Unloading Valve |
| Port size | the listed |
| End connection | VCR face seal, orbital butt weld or compression |
| Actuation | Manual handwheel / normally closed pneumatic (60-90 PSI) |
| Wetted alloy | 316L VIM/VAR standard, nickel-based alloy by gas compatibility |
| Documentation | Material certificate, helium leak record, CoC (state if required) |
Ready to specify the RV?
Send the gas, pressure, flow and connection details — we will confirm the model, materials and lead time.
Related models and alternatives
Other valves in the Cylinder & High Pressure Valves family and adjacent groups that may suit a different Cv, pressure or port requirement.
WRVWRV Adjustable Unloading Valve
- Port size1/4
- Max. pressure1000 PSI
- CvOn request
UCV20UCV20 CGA/DISS Cylinder Valve
- Port sizeOn request
- Max. pressure20 MPa
- CvOn request
CV20LCV20L High Pressure Pneumatic Valve
- Port size3/8, 1/2, 3/4
- Max. pressure20 MPa
- CvOn request
CV20ACV20A Pneumatic Cylinder Valve
- Port size3/4
- Max. pressure20 MPa
- CvOn request
Frequently Asked Questions
What are the key specifications of the RV?
The RV is supplied with the listed ports, a maximum working pressure of the rated and a Cv of a model-specific. End connections are vcr face seal, orbital butt weld or compression. The full specification table on this page lists materials, leak testing, actuation and cleanliness requirements.
Is the RV suitable for corrosive or toxic specialty gases?
It is used with high pressure H2, N2, Ar, He, O2 and cylinder-grade specialty gas mixtures at source pressure. Compatibility depends on the wetted alloy and the sealing element, so state the gas and concentration when requesting a quote and we will confirm the material selection.
How is the RV actuated and what is its safe state?
Standard configurations are a manual handwheel or a normally closed pneumatic actuator with 60-90 PSI instrument air. Pneumatic versions close on loss of air, which is the required safe state for most gas cabinet and tool hook-up isolation points.
How do I order the RV?
Quote model RV together with the gas list, operating pressure, required Cv, port size, end connection and actuation. Material certificates, per-valve helium leak records and a certificate of conformance can be supplied with the order.