Transformer Butterfly Valve: Working Principle, Parameters, Selection Guide & FAQ
The steel plate butterfly valve is a critical component for transformer cooling systems, used to control the flow of cooling oil or air between the transformer main tank and radiators/relays. Below is a complete industry knowledge guide.
1. Working Principle of Transformer Butterfly Valve
A transformer butterfly valve uses a simple yet reliable mechanical principle to regulate flow:
Core Structure: A flat disc (butterfly plate) mounted on a central rotating shaft sits perpendicular to the flow path inside the valve body.
Flow Control:
When the disc is rotated parallel to the flow direction, the valve is fully open, allowing maximum oil flow.
When rotated perpendicular to the flow, the disc blocks the passage, fully closing the valve.
Partial rotation allows precise adjustment of flow rate.
Sealing Mechanism: The disc is fitted with a rubber seal to ensure a tight shutoff, preventing oil leakage when closed.
This design enables quick, reliable on/off control and flow regulation, making it ideal for transformer cooling circuits.
2. Key Technical Parameters
Based on the specifications in the diagram:
Standard Sizes & Dimensions
| Application | Code | DN | D1 | D2 | D3 | A | B | H |
|---|---|---|---|---|---|---|---|---|
| For Heat Sinks | TH.VAF.001 | 50 | 63 | 83 | 125 | 125 | 31 | 156 |
| TH.VAH.001 | 80 | 92 | 115 | 150 | 150 | 31 | 182 | |
| For Relays | TH.VAF.002 | 50 | 63 | 83 | 125 | 93 | 31 | 156 |
| TH.VAH.002 | 80 | 92 | 115 | 160 | 135 | 31 | 192 |
Common Technical Specifications
| Parameter | Details |
|---|---|
| Nominal Diameter (DN) | 50 mm, 80 mm (standard; custom sizes available) |
| Body Material | Steel plate (carbon steel) |
| Seal Material | Oil-resistant rubber (compatible with transformer oil) |
| Operating Temperature | -35°C ~ 105°C (matches transformer oil range) |
| Connection Type | Flange connection (bolt-on to transformer/radiator) |
| Pressure Rating | Designed for transformer cooling circuit pressure (typically up to 1.0 MPa) |
3. How to Select the Right Butterfly Valve
Follow these key steps to choose the correct valve for your application:
3.1 Match the Nominal Diameter (DN)
The valve's DN must match the diameter of the pipe/radiator connection. Common sizes are DN50 and DN80.
Using the wrong size will cause flow restrictions or installation mismatches.
3.2 Choose the Correct Type for Your Application
For heat sinks/radiators: Use the standard butterfly valve (e.g., TH.VAF.001 / TH.VAH.001).
For relays/special circuits: Use the relay-specific valve (e.g., TH.VAF.002 / TH.VAH.002) with modified flange dimensions.
3.3 Check Flange Dimensions
Ensure the bolt hole pattern, diameter (D3), and flange size (A) match the mating connection on your transformer or radiator.
Incorrect flange dimensions will prevent proper sealing and installation.
3.4 Consider Operating Conditions
Temperature: Confirm the valve's temperature rating matches your transformer's operating range (up to 105°C).
Seal Material: Choose oil-resistant rubber seals compatible with mineral transformer oil.
4. FAQ (Frequently Asked Questions)
Q1: What is the purpose of a butterfly valve on a transformer?
A: It controls the flow of cooling oil between the transformer tank and radiators. It allows you to isolate radiators for maintenance without draining the entire transformer, and regulate cooling efficiency based on load.
Q2: Can the valve be installed in any orientation?
A: It is recommended to install the valve with the shaft in a horizontal position to ensure proper sealing and prevent the disc from sticking due to gravity.
Q3: How do I know if the valve is fully open or closed?
A: The valve typically has an indicator on the top of the shaft showing the disc position. Parallel to the pipe = open; perpendicular = closed.
Q4: What maintenance does the butterfly valve require?
A:
Periodically check for leaks around the flange.
Operate the valve (open/close) every 6–12 months to prevent the disc from seizing.
Inspect the rubber seal for signs of aging or damage.
Q5: Can I use a radiator-type valve for a relay connection?
A: No. The flange dimensions (bolt pattern, A/A1 size) are different, and the valve may not seal properly or fit the connection. Always use the valve designed for your specific application.