Shand & Jurs 97190 3-Way Safety Selector Valve

For terminal operators, biogas engineers, and tank-safety designers, the Shand & Jurs Biogas 97190 3-Way Safety Selector Valve allows redundant pressure and vacuum vents or flame arresters to be serviced without depressurizing the protected system.

Unlike conventional practice that requires venting, flaring, or shutting down the tank to remove a relief device, the 97190 directs full relieving flow to the active branch while mechanically sealing the isolated branch, permitting safe removal under live system pressure.

An internal three-way rotor maintains full relieving capacity during changeover, and the anti-dual-block design prevents both branches from being closed simultaneously, so continuous overpressure protection is preserved throughout maintenance.

Rated to 25 PSIG at 100°F (400°F maximum) across 2″–12″ flanged sizes in aluminum or 316 stainless, the 97190 protects tanks, digester covers, vapor headers, and process vessels during routine relief-device service.

Features

Diverter rotor directs full flow to one relief device while isolating the other, and cannot close both paths at the same time.

Isolated branch seals positively, allowing removal of a pressure relief valve or flame arrester for service without depressurizing the vessel or losing containment.

Internal geometry preserves full relieving capacity during changeover and continued operation, so tank protection is never reduced while a branch is isolated.

Lockable nut-drive operator prevents unintended changeover during operation or maintenance, supporting lockout-tagout procedures and verifiable active-path positions.

Clear position indication confirms which relief branch is active at a glance, reducing operator error and supporting documented procedures during changeover steps.

Built-in bleed connections safely vent trapped gas in the isolated branch before removal, and accept pressure indicators to confirm isolation before maintenance begins.

Applications

Redundant PRVs: Enables live isolation of one pressure relief valve in a redundant pair while the second maintains full overpressure protection for the tank or vessel.
Storage Tanks: Preserves continuous relief protection on atmospheric and low-pressure storage tanks during routine PRV service, avoiding tank depressurization and product loss cycles.
Digester Covers: Allows service of pressure-vacuum relief devices on anaerobic digester covers without venting the headspace, maintaining biological process stability and gas containment.
Vapor Headers: Supports inline relief-device isolation on vapor recovery headers, keeping the header under active protection while an individual branch is removed for inspection.
Process Vessels: Installed on low-pressure process vessels where relief redundancy is required and operation cannot be interrupted for individual device maintenance events.
Continuous-Operation Systems: Removes scheduled outages as the only service window for relief devices, extending run time on sites where shutdown costs or production losses are significant.

Specifications

Parameter

Specification

Operating Function

Redundant Relief Selector Valve

Pressure Rating

25 PSIG @ 100°F (400°F maximum)

Sizes

2″ – 12″

Flow Path

Inlet to Outlet A or B; INLET to OUTLET (A/B) or (A&B)

Connections

ANSI 150 RF or 150 FF (RF flange not available for aluminum body)

Operator

Nut Drive

Rotor

Aluminum or 316 Stainless Steel

Hardware

Stainless Steel

Cv Range

2″ 260 | 3″ 620 | 4″ 1070 | 6″ 2720 | 8″ 4520 | 10″ 6935 | 12″ 9947

Optional Accessories

Insulation jacket for cold-climate service; bleed-valve pressure indicators

2026 COST ESTIMATE

Contact Support

If you have questions not covered here, please contact the Cognesense support team for assistance.

Can both relief branches be closed at the same time?

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No. The 97190 uses an anti-dual-block design; the internal three-way rotor directs full flow to one relief device while isolating the other, and is mechanically prevented from closing both paths simultaneously. The vessel is always under active overpressure protection.

How does the 97190 support live relief-valve service?

With the rotor pointed to the active branch, the isolated branch is sealed positively. Integral bleed connections vent trapped gas, and the isolated PRV or flame arrester can be removed for inspection or replacement while the tank remains in operation.

What pressure and temperature is the 97190 rated for?

The valve is rated to 25 PSIG at 100°F, with a 400°F maximum temperature, across 2″ through 12″ sizes. ANSI 150 RF or 150 FF flange connections are available, with RF not offered on the aluminum body.

Can position be locked for procedure verification?

Yes. The operator accepts dual pad locks, preventing unintended changeover during operation and supporting lockout-tagout procedures. A visual indicator confirms the active path and provides verifiable evidence of the operating position.

Is an insulation jacket available for cold-climate installations?

Yes. An insulation jacket is offered to reduce freezing risk and maintain drainage reliability in cold climates. Jacket installations should maintain a heat source as specified, and the jacket protects drainage paths from freeze-related damage.

What is the flow capacity across sizes?

Cv values range from 260 at 2″ to 9947 at 12″ (3″: 620, 4″: 1070, 6″: 2720, 8″: 4520, 10″: 6935). Size selection should match the relieving capacity required by the downstream relief device.

Summary

With over a century of tank-safety heritage inside Cognesense, the Shand & Jurs Biogas 97190 3-Way Safety Selector Valve is chosen when pressure relief must remain active during service. Its internal diverter rotor, anti-dual-block design, and lockable operator let operators isolate a relief device for inspection while continuous protection is maintained through the redundant branch. Installed on tanks, digester covers, and vapor headers, it is trusted wherever you need to measure, monitor, and protect what matters most.

97190 3-Way Safety Selector Valve