Where reliable liquid separation matters
From oil and chemical processing to environmental protection, the Belfield Valve provides automatic phase separation with very few moving parts.
Find the Right Solution for Your Process
Explore your application or prepare the data needed to select a Belfield Valve.
Tank Dewatering
Drain settled water from storage tanks and retain the lighter product with an automatically closing, specific-gravity-operated Belfield Valve.
Chemical Decantation
Automate the discharge of separated liquid phases in suitable chemical batch and washing duties, with selection based on your process.
Effluent Protection
Help retain unwanted product at the vessel discharge point before it can reach downstream effluent-treatment equipment.
Size Your Valve
Start with your liquids, flow and available head. Use published model data to prepare an enquiry, not an automatic selection.
Liquid separation across demanding industries
The Belfield Valve is a proven solution for phase separation and liquid recovery across a wide range of oil and process-industry applications. Designed for precision and efficiency, it is used in crude-oil storage, reclaimed-oil recovery, floating-roof tank drainage and effluent management.
The valve can be used for practically any decanting operation within the limits of its capacity, pressure and temperature parameters. Whether the priority is preventing contamination, improving separation, recovering product or supporting environmental compliance, the Belfield Valve provides automatic mechanical phase detection.
A proven method for separating the heavier of two liquids
The Belfield Decantation Valve provides a sensitive, versatile alternative to manual decanting across multiphase systems. It responds automatically to the change in specific gravity as the interface reaches the valve.
No waste
Reduces product loss caused by human error, particularly where there is little or no visible colour difference between phases.
Detection
Detects and retains or rejects valuable interface materials that may contain recoverable product.
Safety
Can act as a safeguard on effluent discharge systems, reducing the risk of pollution from oil, solvent or chemical release.
Automatic
Requires minimal routine attention, service and maintenance, helping reduce labour associated with manual decanting.
Robust materials
Standard body construction is carbon steel or stainless steel; internal components are stainless steel in both cases.
Gravity or pumped
The operating principle can be applied to gravity-fed and pumped discharge systems when correctly sized for the duty.
Crude-product and reclaimed-oil tanks
Drainage of water from crude product tanks and reclaimed oil tanks.
Every refinery also has reclaimed-oil tanks for storage of oil recovered from spillage that reaches refinery API separators, where it is skimmed off and pumped to the reclaimed-oil tank. Relatively large proportions of water may also be pumped into these tanks or settlers; after separation from the oil, the water run-off rate can be high.
Numerous Belfield Valves are used for this duty, with specially enlarged equilibrium valves and connections available to help avoid blockage. The resulting water is often heavily laden with suspended solids, which the valve is designed to handle.
- Water drainage from crude-product storage tanks.
- Reclaimed-oil recovery after API separation.
- Handling water containing suspended solids.
- Gravity-fed or pumped transfer systems.
- Product recovery where clear visual phase identification is difficult.
Continuous drainage of rainwater from floating roofs
Refineries use floating-roof tanks for crude storage and other large-capacity duties. This design presents two potential problems:
- The roof may sink if accumulated rainwater is not drained.
- Tank contents may be discharged to the ground or drains if an internal articulated drain joint or hose fails.
A Belfield Valve can be installed on the drain connection at the tank side. With the optional swan-neck outlet, the valve is arranged to remain open while water is present, whether flowing or static, while preventing the outlet from siphoning. When rain falls, water can pass from the roof through the internal drain and out through the Belfield Valve.
If a drain joint or hose leaks, the valve senses the change in specific gravity and closes, helping prevent product from entering drains or contaminating the ground. Optional magnetic proximity devices can indicate whether the float is open or closed and can be arranged for hazardous-area applications. This can provide a remote alarm if the float closes and help reduce the risk of the roof sinking. Float-position sensing is available on the MS/STD model.
Helping protect effluent-treatment systems
The Belfield Valve is increasingly specified on environmental-protection grounds. Wherever wastewater is decanted from process or storage vessels to an effluent-treatment plant, the valve can be applied as an automatic protection device.
By responding to a change in specific gravity, it helps minimise the possibility of accidental discharge of oil, solvents or chemicals into the final effluent-treatment system.
One valve can serve changing two-phase duties
Many different two-phase systems may pass through the same batch vessel or be used through a series of washings. Multiple valves are not necessarily required, provided operating temperatures are reasonably similar and both phases have comparable specific-gravity behaviour with temperature.
The closest approach of the two specific gravities can be established and the float ballasted accordingly. The valve then operates even more decisively where the specific gravities diverge. Where process conditions vary, provide the maximum available information on the specific gravities and temperatures of both phases for each system or wash, and contact PMA for application assistance. Chemical duties may use gravity discharge, pumped discharge or a combination of both, with pumped systems often predominating.
Typical two-phase systems
- Toluene / Water
- Benzene / Water
- Xylene / Water
- Nitrobenzene / Acid
- Nitrobenzene / 70% Sulphuric Acid
- Toluene / Dichloraniline
- Ortho-dichlorobenzene at 80°C
- Organic material / 10% Sulphuric Acid at 90°C
- Aniline / Water at 60°C
- Sodium Sulphite / Organic Nitrile Oil
- Naphtha / Water
- Petroleum Spirit / Water
- Heavy Fuel Oil / Water
- Gas Oil / Water
- Light Distillate / Water
- Aviation Spirit / Water
- Aviation Spirit / Paraffin
Storage drainage and wash-material recovery
Applications include drainage of water from storage tanks, recovery of wash materials such as toluene and xylene, and the final stages of intermediate or finished liquid-base products.
Examples of materials handled
- Epichlorohydrin / Water
- M.E.K. / Water
- MKB / Water
- Toluene / Water
- Benzene / Water
- Trade-name organic materials / Water
Recovering oil for reprocessing
These applications are based mainly on distillation. Water may need to be drained from recovered product and from feed material entering the plant.
Heavy-engineering processes use large volumes of hydraulic and quench oils that are recovered for reprocessing. These oils can become contaminated with significant quantities of water, which is removed after separation in underground sumps or above-ground tanks.
Industries include
- Aluminium production
- Plastic extrusion
- Drop forging
- Engine manufacturing
Dawcul is the official international distributor of the Belfield Decantation Valve
Dawcul is our trusted international distributor, providing global access to our industry-leading liquid separation technology. With decades of experience supplying engineering solutions to the oil, gas and petrochemical industries, Dawcul supports seamless ordering, technical guidance and delivery around the world.
Let’s talk about your application.
Speak to the PMA team about your Belfield Valve requirements. Tell us about your liquid-separation duty, and we’ll help you find the right next step.
- Advice for your application. Discuss the liquids, flow rate and operating conditions for your process.
- Practical valve support. Get help with sizing, installation, maintenance and replacement parts.
- Clear next steps. Request a quotation or a callback, with your site and application in mind.
- An enquiry, not a mailing list. Your details are used to respond to your enquiry.
Belfield Valve customers
Prefer to speak with us?
You can also email sales@pma.uk.com.
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. Read our privacy policy.