Reliable Transformer &
Cable Accessory Solutions

Source factory-direct components with stable quality, practical lead times, and export-ready support.

  • ISO 9001 Certified Quality
  • Factory Direct OEM/ODM Support
  • Fast Global Delivery

Request A Quote

Fill out the form below to receive our catalog and pricing.

Contact Form Demo
Transformer Accessories Series

Transformer Valves for Oil-Immersed Transformers

Radiator butterfly valves, ball valves, drain and sampling valves, and check valves for oil-immersed transformer systems.

Four Valve Series Connection Options Technical Catalogues
Request Quote View Specifications
Product RangeFour Valve Families
System LocationsRadiator, Tank & Oil Circuit
ApplicationOil-Immersed Transformers
Product Definition

Match the Valve to Its Role in the Oil System

Transformer valves provide access and control at radiator connections, oil drain points, and cooling pipework. The right choice begins with the operating duty, followed by the connection geometry, materials, and service conditions.

  • 1
    Isolation & Routing — butterfly and ball valve configurations serve radiator and oil pipe connections.
  • 2
    Drainage & Sampling — dedicated drain valves combine an oil outlet with an oil sampling port.
  • 3
    Reverse-Flow Control — check valves serve forced oil circulation systems, commonly at the pump outlet.
Choose the required function first. A matching nominal size alone does not establish interchangeability between valve designs.
Radiator ConnectionButterfly Valve
Oil Pipe Isolation / RoutingBall Valve
Oil Drain & Sample PointDrain Valve
Pump Outlet / Cooling CircuitCheck Valve
Series Configurations

Choose the Right Transformer Valve Series

Compare the four product families by function and construction. Each catalogue provides the corresponding series details for quotation and drawing review.

Radiator butterfly valve for transformer oil pipe connections

Radiator Butterfly Valves

Select metal-to-metal seated or single-eccentric soft-seal construction for radiator connections. Seat selection affects shut-off performance and seal maintenance.

  • DesignsMetal seat / Soft seal
  • Metal-seated sizesDN25–DN350
  • Primary dutyRadiator isolation
Selection FocusConfirm the seat design, body shape, bolt pattern, and required leakage acceptance criteria.
Request QuoteCatalogue PDF
Transformer ball valve product view

Ball Valves

Ball valves serve transformer drainage and radiator pipework. Connection options include flanged, threaded, and welded types, with T-port and L-port three-way configurations also available.

  • ConnectionsFlanged / Threaded / Welded
  • Flanged sizesDN15–DN200
  • Three-way flow pathsT-port / L-port
Selection FocusSpecify the connection and flow path. Confirm a full-port design where bore area is a selection requirement.
Request QuoteCatalogue PDF
Forged brass transformer oil drain valve with sampling port

Drain & Sampling Valves

Forged brass drain valves combine handwheel operation with an oil sampler and a chained outlet cap or plug for transformer oil service.

  • Threaded sizes1 in / 2 in NPT
  • Valve bodyForged brass
  • Service featureOil sampling port
Selection FocusCheck access for the handwheel, drain connection, and sampling operation at the tank outlet.
Request QuoteCatalogue PDF
Transformer check valve for forced oil circulation systems

Check Valves

Dual plate and single disc swing designs control reverse flow in forced oil circulation systems. Selection depends on the pump and cooling circuit arrangement.

  • DesignsDual plate / Single disc swing
  • Dual plate connectionsWafer / Flange
  • Single disc connectionFlange
Selection FocusProvide pipe size, flow direction, installation orientation, and pump operating conditions.
Request QuoteCatalogue PDF

Additional Product Views

Radiator butterfly valve additional product view
Radiator Butterfly Valve
Transformer drain and sampling valve additional product view
Drain & Sampling Valve
Transformer check valve additional product view
Check Valve
Technical Data

Engineering Specifications by Configuration

Use these configuration-specific values to narrow the selection, then match the final assembly to your project drawing.

A. Metal-Seated Butterfly Valves

ParameterConfiguration Details
Nominal sizeDN25, 40, 50, 80, 100, 125, 150, 175, 200, 250, 300, 350
Body materialsCarbon steel / Stainless steel / Ductile iron
Body formsSquare, round, X-shaped, and rectangular; availability depends on size
MountingSelect the bolt circle, hole type, and thickness from the relevant drawing
Design / test referenceBS/EN 50216-8, as listed in the catalogue
TemperatureConfiguration-dependent temperature options; confirm the complete valve for the intended duty

B. Flanged Ball Valves

ParameterConfiguration Details
Nominal sizeDN15, 20, 25, 32, 40, 50, 80, 100, 150, 200
Body materialsCarbon steel / Stainless steel
Carbon steel temperature−30 to 160 °C
Stainless steel temperature−46 to 160 °C
Flange referencesASME B16.5, EN 1092, GOST 12815/33295
Configuration scopeThese values apply to the flanged type; confirm three-way, threaded, and welded versions separately

C. Drain & Sampling Valves

ParameterConfiguration Details
End connection1-inch or 2-inch NPT threaded ends
Valve bodyForged brass
Connection fittingsBrass / Stainless steel
End plugBrass / Stainless steel
OperationHandwheel, with oil sampler

D. Check Valves

ParameterConfiguration Details
Dual plate materialsCarbon steel / Stainless steel / Bronze
Dual plate connectionsWafer / Flange
Single disc swing typeFlanged connection
Sizing inputsPipe size, flow rate, pressure duty, and installation orientation

Dimensions & Operating Conditions

  • Metal-seated butterfly valve data do not define the soft-seal version. Some nominal sizes have several mounting configurations.
  • Confirm pressure rating, oil compatibility, temperature, and connection dimensions for the selected valve before ordering.
  • For butterfly valves, seal-material temperature limits do not replace the complete valve operating limits.
Project Supply

Valve Selection for OEM & Replacement Projects

A clear enquiry connects the required valve function with the mechanical interface and supply scope.

OEM Transformer Assemblies

Match radiator, tank, and cooling circuit valves to the equipment layout and purchasing specification.

Replacement Applications

Send the existing valve drawing or measured connection details to assess a replacement configuration.

Material Selection

Identify the required body, seat, shaft seal, and exposed fitting materials for the operating environment.

Connection Matching

Include the flange drilling, thread designation, or weld-end requirements in the enquiry.

Order Scope

List quantities by configuration, including any requested caps, plugs, fittings, and documentation.

Project Scheduling

Share the required delivery date and destination so availability and shipment details can be addressed in the quotation.

Discuss Your Valve Requirements
Selection Guide

How to Specify Your Transformer Valve

These five steps help define a valve that fits both the oil circuit and the installation space.

01

Define the Duty

Identify radiator isolation, oil routing, drainage and sampling, or reverse-flow control.

02

Set Service Conditions

Provide oil type, operating temperature, pressure, and any vacuum requirements.

03

Match the Connection

State DN/NPS, flange standard and drilling, thread size, or weld-end details.

04

Check Installation

Review face-to-face dimensions, operating clearance, flow direction, and mounting orientation.

05

Agree the Order

Confirm the configuration, quantity, drawings, acceptance criteria, and required documents.

Common Selection Mistakes

  • Using nominal size alone to approve a replacement.
  • Applying flanged ball valve ratings to a three-way version.
  • Assuming a metal-seated butterfly valve provides zero internal leakage.

Information to Include in Your RFQ

  • Valve duty, configuration, and quantity
  • Operating conditions and connection dimensions
  • Drawing or existing valve reference
  • Required documents, delivery date, and destination

Send Your Requirements to ZeeyiElec

Quality & Documentation

Technical Requirements & Product Catalogues

Use the series catalogue for initial selection and define the inspection and documentation scope with your order.

Technical Review Before Ordering

  • Configuration & DrawingConfirm the selected construction, materials, connection, and key dimensions against the order requirements.
  • Operating LimitsAgree the applicable pressure and temperature limits for the valve assembly and intended oil service.
  • Inspection & AcceptanceState the required dimensional checks, leakage criteria, and test documentation in the enquiry.
  • Supply DocumentationSpecify material records, inspection reports, and export documents required by your project; confirm the available scope with the quotation.

Download the Series Catalogues

Open the relevant PDF to review product configurations and the technical information for your selected series.

Drawing & Specification Enquiries

Send your connection drawing and operating requirements when requesting a quotation. For replacement work, include the existing valve dimensions and available installation clearance.

Contact ZeeyiElec for Technical Details
FAQ & Resources

Common Transformer Valve Questions

Answers to the configuration and compatibility questions that matter during selection.

Related Resources

Which valve should I use at a transformer radiator?
Butterfly valves are commonly used at radiator connections. Ball valves are another option for radiator pipework. Select against the required connection, available space, operating conditions, and shut-off criteria.
How do metal-seated and soft-seal butterfly valves differ?
The metal-seated design uses metal-to-metal seating and should not be specified on a zero-leakage assumption. The single-eccentric soft-seal design uses a sealing ring; oil compatibility, ageing, and maintenance requirements need consideration.
Do the ball valve specifications also apply to three-way valves?
The DN15–DN200 range, temperature values, and flange references above apply to the flanged type. For a three-way valve, specify T-port or L-port and the required connection, then confirm its dimensions and operating limits separately.
Which drain valve sizes and materials are available?
The drain valves are available in 1-inch NPT and 2-inch NPT sizes. Both use a forged brass body with an oil sampler. Brass or stainless steel options apply to the connection fittings and end plug.
What is needed to select a transformer check valve?
Provide the pipe size, oil flow rate, pump conditions, pressure duty, and installation orientation. The range includes dual plate wafer or flanged designs and a flanged single disc swing design.
Can I select a replacement from a photograph?
A photograph helps identify the construction, but dimensional matching is also necessary. Include the bore size, connection details, bolt pattern or thread, overall dimensions, and operating conditions with your enquiry.