Suspended solids & SVI analysis.Discover S3A

Belfield valve sizing & selection

Bring liquid properties, flow and installation conditions together to select the model and float setting.

Specify the duty, not just the pipe size

The valve body and float setting must suit the actual phases and installation. Required flow, available head and downstream conditions affect capacity; the specific-gravity difference determines the phase-response duty.

The published figures provide a starting point for selection. They are not a guarantee of flow across all liquids, temperatures and pipework arrangements.

Send PMA the process data and a vessel or P&ID sketch so the model, wetted materials and configuration can be reviewed together.

PMA team planning a Belfield valve application in a meeting room

Compare the published model range

The brochure lists two carbon steel models and three stainless steel models. Confirm current availability and the configuration for your application.

Nominal capacities at a reference head of 25 ft (7.5 m). Capacity is in imperial gallons per hour; connection sizes are in inches.
Model Capacity
imp gal/h
Inlet
in
Main outlet
in
Side run-off
in
MS/LC 1,500 2 1½ 1½
MS/STD 10,000 4 2 2
SS6 1,500 2 1 1
SS8 3,000 3 2 2
SS10 10,000 4 2 2

These are published reference capacities, not guaranteed flows for every installation. Confirm the actual liquid properties, head, temperature, pressure and discharge conditions before choosing a model.

Conditions that change the selection

Pressure & head

The published design pressure is 75 psig; hydrostatic test pressure is 112.5 psig. The capacity table uses a 25 ft (7.5 m) reference head. Test pressure is not an operating rating.

Temperature

For the brochure’s atmospheric-discharge duty at up to 50 ft (15 m) head, water up to 80°C uses nominal capacity. From 80–95°C, the brochure specifies a 25% reduction. Other conditions need review.

Viscosity

Up to 50 cSt at operating temperature has little or no effect on published capacity. From 50–100 cSt, the brochure specifies a 25% reduction; consult PMA above 100 cSt.

Liquid density

Review both specific gravities at operating temperature, especially the smallest difference expected. The average 5% figure does not establish suitability for every liquid pair.

Solids, wax & emulsions

State any suspended solids, wax, persistent emulsion or flashing tendency. Low-flow duties with solids need particular review, including inspection and cleaning arrangements.

Connections & materials

Do not reduce the inlet below the stated model size. Confirm outlet restrictions, downstream pressure, material and seal compatibility before specifying the pipework.

Prepare a complete selection enquiry

Liquid properties

Identify both phases, their specific gravities and viscosities at operating temperature. Include solids, emulsions and wax where present.

Process conditions

Provide minimum, normal and maximum temperature and pressure, required flow, available head and downstream backpressure.

Installation & materials

Include connection sizes, wetted-material and seal requirements, the discharge route, and a vessel or P&ID sketch.

Over 50 years of process expertise

PMA has supported process measurement and analysis since 1971. We bring the valve and its application together: the liquids, the vessel, the discharge route and the information your team needs.

Share your process conditions and a vessel or piping sketch. Our team can help you review selection, installation requirements and ongoing support.

Technical resources

Belfield valve brochure

Published operation, materials, model capacities and application limits.

Operating manual

Installation and operating guidance for the configured valve and process duty.

Dedicated Belfield website

Explore the wider Belfield technical library and application background.

Belfield valve questions

Is 112.5 psig the working pressure?

No. The brochure identifies 75 psig as the design pressure and 112.5 psig as the hydrostatic test pressure. Final operating conditions must match the reviewed configuration.

Can the listed capacity be used directly for a quotation?

It is a nominal reference figure at 25 ft (7.5 m) head. Actual liquids, viscosity, temperature, available head, downstream conditions and pipework must be considered.

Does the 95°C figure apply to every installation?

No. The brochure qualifies its temperature guidance for atmospheric discharge at up to 50 ft (15 m) head and specifies a capacity reduction from 80–95°C. Higher head, other pressures or temperatures require review.

Let’s talk about your application.

Speak to the PMA team about your instruments, reagents or service requirements. Tell us what you need, and we’ll help you find the right next step.

  • Advice for your application. Find the right instruments, sensors and chemical reagents for your process.
  • Practical service support. Discuss commissioning, calibration, maintenance or an instrument issue with our team.
  • Clear next steps. Ask a technical question or request a callback, with your site and measurements in mind.
  • An enquiry, not a mailing list. Your details are used to respond to you. You won’t be added to a marketing database.

Trusted by our clients

Prefer to speak with us?

Call 01484 843 708

You can also email [email protected].

Tell us how we can help

Share your requirements below. All fields are required.


Your enquiry goes directly to our team. Your details are used to respond to you, and you won’t be added to a marketing database. Read our privacy policy.