The 2‑Valve Manifold is used in conjunction with pressure transmitters or pressure gauges. Its function is to connect or disconnect the positive and negative pressure chambers of a differential pressure transmitter to/from the pressure tapping points, or to connect or disconnect the positive pressure chamber from the negative pressure chamber. It is generally used in on‑site control instruments to provide multiple channels for the instrument, reduce installation workload, and improve system reliability. The 2‑Valve Manifold is connected to the process interface of the transmitter, with common specifications of 1/2 NPT and 1/4 NPT. The inlet part has the same specification as the pipeline, with common technical parameters of φ12, φ14, φ16, and φ18.

Working Principle

The 2‑valve manifold consists of two independent valves, commonly used for protection and venting operations of pressure transmitters.

Isolation Valve: It isolates the pressure transmitter from the process pipeline. After closing, maintenance or replacement of the transmitter can be carried out.

Vent Valve: It releases residual medium inside the pressure transmitter for safe operation or calibration.

The 2‑valve manifold is designed for single‑point pressure measurement scenarios, such as oil‑gas transmission pipelines and boiler pressure monitoring.

Technical Parameters of 2‑Valve Manifold

Grease on upper valve stem thread is isolated from the system medium.

Non‑rotating valve tip reduces galling between the valve seat and valve head.

The valve provides backseat function at fully open position.

The handle is fastened with screws at both ends for stable performance.

Factory pressure test is performed.

Each valve shall pass tightness test with nitrogen under working pressure.

Classification and Types of 2‑Valve Manifold

Classified by Structure

Integral 2‑Valve Manifold: The block valve and vent valve are integrated on one single valve body. It features compact structure and fewer leakage points, suitable for high‑pressure service.

Split‑body 2‑Valve Manifold: Two valves are connected by short pipe. It provides flexible installation and allows separate valve replacement, widely used in low‑pressure systems.

Classified by Connection Type

Threaded Connection: NPT, M‑thread and other threads are adopted. Applicable for DN10‑DN20 pipe size, such as front‑end connection for pressure gauge.

Ferrule Connection: Sealed by ferrule compression, suitable for stainless steel tubing for fast installation, commonly used in laboratory instruments.

Features of 2‑Valve Manifold

Simple Structure: Assembled by only two valves, lower cost than 3‑valve or 5‑valve manifold, and requires small installation space.

Integrated Basic Functions: It realizes medium shut‑off and pipeline venting, meeting maintenance requirements of simple measurement systems.

Convenient Operation: Clear on‑off status for quick field switching.

Limitations: Without balancing valve design, it cannot be used for differential pressure measurement. Its pressure‑shock resistance is relatively weak.

Application Fields of 2‑Valve Manifold

Single‑point pressure measurement scenarios:

Industrial Sites: Pipeline pressure monitoring, directly connected with pressure transmitters or pressure gauges.

Water Treatment System: Pressure detection at pump outlet, differential pressure measurement before and after filters.

Laboratory Equipment: Pressure monitoring for gas analyzers and small‑size reaction kettles, widely adopted for simple system and low‑cost advantage.

Low‑pressure non‑corrosive media: Water, air, nitrogen and others. For corrosive gas service, stainless‑steel 2‑valve manifold shall be selected.