Pressure Relief Valve — YSF Series
Spring-loaded, rapid-opening valve mounted on the transformer tank. When internal pressure exceeds the set value — during an internal fault or oil overpressure — the valve opens within milliseconds to discharge oil and gas, then reseals automatically.
- YSF-35/25(SKJD)
- YSF-35/50KJ(SD)
- YSF-55/50KJ(SD)
- YSF-55/80KJ(SD)
- YSF-55/130KJ(SD)
- YSF-70/130KJ(SD)
- YSF-85/130KJ(SD)
- YSF-138/130KJ(SD)
Model format: YSF-(opening pressure)/(effective diameter)(option codes). KJ = electric and mechanical signal switch · D = directional pilot injection · TH = damp-hot / TA = dry-hot environment (omitted for general areas).
Technical Data
Values below are taken from the manufacturing partner's published catalogue.
| Model | Opening pressure | Effective diameter | Signal switch | Pilot injection |
|---|---|---|---|---|
| YSF-35/25(SKJD) | 35 kPa | Φ25 mm | Yes | Yes |
| YSF-35/50KJ(SD) | 35 kPa | Φ50 mm | Yes | Yes |
| YSF-55/50KJ(SD) | 55 kPa | Φ50 mm | Yes | Yes |
| YSF-55/80KJ(SD) | 55 kPa | Φ80 mm | Yes | Yes |
| YSF-55/130KJ(SD) | 55 kPa | Φ130 mm | Yes | Yes |
| YSF-70/130KJ(SD) | 70 kPa | Φ130 mm | Yes | Yes |
| YSF-85/130KJ(SD) | 85 kPa | Φ130 mm | Yes | Yes |
| YSF-138/130KJ(SD) | 138 kPa | Φ130 mm | Yes | Yes |
Flange mounting dimensions (mm)
| Size | Oil nozzle Ø | Outside Ø D | Connecting pipe Ø × d | Body height H | Hole centre Ø | Bolt holes | Sealing ring Ø A | Spray cover Ø B |
|---|---|---|---|---|---|---|---|---|
| JB/4 | 25 | 112 | 45 | 105 | 90 | M12 × 3 | 64 | 60 |
| JB/5 | 50 | 160 | 80 | 150 | 130 | M12 × 4 | 106 | 100 |
| JB/6 | 80 | 195 | 130 | 230 | 170 | M14 × 6 | 150 | 170 |
| JB/7 | 130 | 265 | 155 | 270 | 234 | M18 × 6 | 200 | 224 |
Basic parameters
| Oil nozzle Ø | Outside Ø D | Tank cover hole Ø | Body height H | Cover + body height | Thread × pitch |
|---|---|---|---|---|---|
| Φ25 | 60 | 40 | 70 | 90 | 38 × 2 (33 × 2) |
| Φ50 | 100 | 80 | 80 | 105 | 60 × 2 |
The valve opens automatically when tank pressure reaches the set value and reseals itself afterwards, keeping internal pressure normal. Outdoor construction; Φ50, Φ80 and Φ130 products are available with the electric signal switch. Opening pressure must match your transformer's tank design — send us the nameplate data and we will confirm the correct setting.
Compliance
Documents are matched to the models and the destination country on your order.
Test and conformity documents applicable to the models you buy are supplied as copies with your quotation and again with the shipping documents. Tell us the destination country and any standard you must satisfy when you enquire — we confirm what can be supplied before you commit.
Document availability is confirmed per model and destination before you order. See how we handle quality & compliance →
Frequently Asked
How do I choose the opening pressure?
It is set according to the tank's withstand pressure — usually specified by the transformer manufacturer. Tell us the transformer model or nameplate data and we will confirm the correct setting with the factory.
Does the valve need maintenance after operation?
The valve reseals automatically after discharge, but any operation should be investigated. We supply replacement gaskets and full valve units.
Need a specific opening pressure?
Send the transformer nameplate — we confirm the setting and quote within 24 hours.