Generant Cryogenic Relief Valve, 1/2" MNPT, 10 to 350 PSI, -320 F
ABOUT THIS PART
Generant brass cryogenic relief valve, 1/2 in MNPT male, factory set and permanently locked. Six set pressures from 10 to 350 psi (0.7 to 24.1 bar). $84.00, with the 10 psi (0.7 bar) on clearance at $60.00.
Buy this size because your port is 1/2 in. It does not relieve faster than the 1/4 in valve.
The short version
- Connection: 1/2 in MNPT male, port code 500B
- Orifice: 0.250 in (6.35 mm), the same orifice as the 1/4 in valve, so capacity is identical
- Flow: 57 SCFM at a 100 psi (6.9 bar) setting, per 3P Certz engineering report ECR-250902-R0
- Full rated flow at 110 percent of set pressure. Back pressure to 10 percent has no effect on the setting
- Brass body, 302 stainless or 17-4PH spring, seal changes with set pressure
- Set pressure is factory locked and stamped on the valve. It is not adjustable
- Not ASME coded. The stamped relief we stock is the Generant RVA, also 1/2 in, in 22 and 100 psi (1.5 and 6.9 bar)
- Cleaned and packaged for oxygen service, 100 percent factory tested, screened Dirt Guard poppet
Set pressures and price
| Set pressure | Price |
|---|---|
| 10 psi (0.7 bar) | $60.00, clearance |
| 22 psi (1.5 bar) | $84.00 |
| 50 psi (3.4 bar) | $84.00 |
| 100 psi (6.9 bar) | $84.00 |
| 250 psi (17.2 bar) | $84.00 |
| 350 psi (24.1 bar) | $84.00 |
The 10 psi is being cleared from stock. Same valve, same factory setting, same warranty. When they are gone the price returns to $84.00.
1/4 inch or 1/2 inch
| 1/4 in CRV | 1/2 in CRV | |
|---|---|---|
| Connection | 1/4 in MNPT | 1/2 in MNPT |
| Orifice | 0.250 in (6.35 mm) | 0.250 in (6.35 mm) |
| Relieving capacity | Identical | Identical |
| Set pressures offered | Nine, 10 to 350 psi (0.7 to 24.1 bar) | Six, 10 to 350 psi (0.7 to 24.1 bar) |
Choose by the port on your vessel, not by expected flow, and do not adapt a 1/4 in valve up to a 1/2 in port.
How cold it goes depends on the set pressure
| Set pressure | Seal | Temperature range |
|---|---|---|
| 10 to 49 psi (0.7 to 3.4 bar) | Fluorosilicone | -85 F to 350 F (-65 C to 176 C) |
| 50 psi (3.4 bar) and above | PCTFE | -320 F to 165 F (-196 C to 74 C) |
The 10 psi and the 22 psi are not -320 F (-196 C) valves. For genuinely cryogenic service order 50 psi (3.4 bar) or higher.
Which pressure goes where
| Location on a 20 LB system | Set pressure |
|---|---|
| Solvent vessel | 250 psi (17.2 bar) |
| Solvent vessel jacket | 100 psi (6.9 bar) |
| Chiller line and jacket inlets | 22 psi (1.5 bar) |
| Material column | 250 psi (17.2 bar) |
| Color remediation column | 250 psi (17.2 bar) |
| Recovery vessel | 250 psi (17.2 bar) |
| Molecular sieve | 250 psi (17.2 bar) |
| CO2 supply | 350 psi (24.1 bar) |
| Manifold | Varies by build |
From 3P Certz Certificate of Conformance 3PC0930. Your build sheet governs.
When to replace
| What the valve does | Replace at |
|---|---|
| Pops off constantly | 3 months |
| Just sees cold and discolors | 6 months |
| Neither of those | 12 months |
Discoloration means cold cycling. More on choosing a relief: Cryogenic relief valve selection.
Usually on the shelf and ships from Bend, Oregon. When a set pressure is out, figure one to two weeks.
SPECIFICATIONS
▦ IN YOUR MANUAL
This part appears in the operator manual that ships with your system. The QR code there links to this page.
◈ REFERENCE FOR THIS PART
COMMON QUESTIONS
Does the 1/2 inch relief valve flow more than the 1/4 inch?
No. Both use a 0.250 inch (6.35 mm) orifice, so relieving capacity is the same. Generant states it in their product literature and our own 3P Certz report ECR-250902-R0 lists the same orifice for both. Choose by the port on your vessel, not by expected flow.
Then why buy the 1/2 inch?
Because your port is 1/2 inch. Fitting the right thread without an adapter is the whole reason. Do not adapt a 1/4 inch valve up to a 1/2 inch port.
Is the set pressure adjustable?
No. Every Generant CRV is factory preset and permanently locked, and permanently stamped with the part number and the setting. It cannot be altered in the field.
Is the 10 psi valve rated to -320 F (-196 C)?
No. At 10 to 49 psi (0.7 to 3.4 bar) the seal is Fluorosilicone and the rating is -85 F to 350 F, which is -65 C to 176 C. At 50 psi (3.4 bar) and above the seal is PCTFE and the rating is -320 F to 165 F, which is -196 C to 74 C.
What flow rate does this valve relieve?
Our third party certification report, 3P Certz ECR-250902-R0, publishes 57 SCFM for the 100 psi (6.9 bar) valve at set pressure through a 0.250 inch orifice. Actual capacity depends on the medium, the set pressure and the back pressure.
Which set pressure goes where on a 20 LB system?
250 psi (17.2 bar) on the solvent vessels, material columns, color remediation column, recovery vessel and molecular sieve. 100 psi (6.9 bar) on the jackets. 22 psi (1.5 bar) on the chiller line and jacket inlets. 350 psi (24.1 bar) on the CO2 supply. From 3P Certz Certificate of Conformance 3PC0930, and your build sheet governs.
How often should a relief valve be replaced?
A valve that pops off constantly should be replaced every 3 months. A valve that just sees cold and discolors is closer to 6 months. A valve that rarely lifts goes 12 months. Discoloration means cold cycling.
Is this an ASME coded relief valve?
No. This is the brass CRV. The ASME BPVC Section XIII coded and National Board stamped valve is the Generant RVA, also 1/2 inch MNPT, stocked in 22 and 100 psi (1.5 and 6.9 bar).
Why is the 10 psi cheaper?
It is being cleared from stock. Same valve, same factory setting, same warranty. When they are gone the price returns to $84.00.
How accurate is the set pressure?
Per EN ISO 4126-1, plus or minus 5 percent at or below 28.90 psi (1.99 bar), plus or minus 1.45 psi (0.10 bar) from 29.00 to 48.30 psi (2.00 to 3.33 bar), and plus or minus 3 percent at or above 48.40 psi (3.34 bar).
What is the lead time?
Usually on the shelf and ships from Bend. When a set pressure is out, lead time is typically one to two weeks, and the longest we have ever seen is 12 weeks.