3-Valve Manifolds
Block, equalize and calibrate differential pressure transmitters safely — two block valves and a central equalizer in one compact body, without interrupting the process.
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BETLOCK 3-Valve Manifold
The 3-Valve Manifold is a valve assembly used with differential pressure (DP) transmitters to safely isolate, equalize, and calibrate the instrument without interrupting the process. It consists of two block valves, one on the high-pressure side and one on the low-pressure side, and a central equalizing valve. Closing the block valves and opening the equalizer isolates the transmitter from the process and equalizes pressure across both sides, allowing the zero reading to be checked or adjusted safely. This protects the transmitter’s diaphragm from overrange damage during isolation and startup, and simplifies calibration and maintenance without depressurizing the process line.
Bhavyam offers all BETLOCK manifolds and valves under the BETLOCK range of products. Design & engineering is done as per global standards to meet challenging process demands.
Specifications
| Product type | 3-Valve Manifold |
| Configuration | 2 block valves + 1 equalizing valve |
| Instrument connection | 1/2" NPT female, flanged to transmitter flange standard |
| Process connection | 1/2" NPT male, flanged |
| Body materials | Stainless steel 316/316L, Carbon steel, Duplex, Monel, Hastelloy, others on request |
| Packing | PTFE, Graphite for high temperature |
| End connections | NPT threaded, socket weld, flanged (direct mount to transmitter) |
| Mounting | Direct mount or remote mount with bracket |
| Testing | PMI, Dimensional test, Hydrostatic test, and others on request |
Frequently asked questions.
What is a 3-valve manifold and why is it used with DP transmitters?
A 3-valve manifold is used with differential pressure transmitters to allow safe isolation, equalizing, and zero calibration without removing the transmitter from service or depressurizing the process line. It protects the transmitter from being exposed to a one-sided pressure spike that could damage its sensing diaphragm.
How does the equalizing valve work in a 3-valve manifold?
The equalizing valve connects the high-pressure and low-pressure sides of the manifold internally. When the block valves are closed and the equalizer is opened, pressure on both sides of the transmitter becomes equal, allowing the zero reading to be checked or adjusted safely before returning the transmitter to service.
What is the correct valve sequence when isolating a transmitter with a 3-valve manifold?
The typical sequence is: close the low-pressure block valve, open the equalizing valve, then close the high-pressure block valve, which safely isolates and equalizes the transmitter. The reverse sequence is used when returning the transmitter to service, closing the equalizer last, after both block valves are open, to avoid a pressure spike across the diaphragm.
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