Blower Protection Valves (Blower Safety Valve)

A range of pressure air recirculating valves (sometimes referred to as Blower Relief Valves), designed to protect your blower against excessive back pressure, which can cause overheating, reduced performance and service life.

The HR Blowers UK Ltd’s range of blower relief valves are designed to protect the blower from system over pressure, venting the excess pressure to atmosphere to protect the blower. Over pressure in the system can cause the blower to overheat reducing the life of the components and in severe cases, complete failure. The valve connections can be manufactured to suit any Customer’s requirements.

Need help sizing your blower? The HR Blower engineering team are here to assist. Contact us today.

Our new valve range has been redesigned to be compact and uses fewer components for improved reliability and cost efficiency. Blower protection valves are available with factory pre-set relief pressures and can also be set to your specific requirement. As our valves are manufactured here in the UK they are available from stock. The valves are manufactured from durable materials to ensure long life in the harshest conditions:


  • Aluminium tube casing
  • Brass valve bell
  • Stainless steel spindle
  • Zinc plated mild steel spring

Sizes and connections

Nominal diameter Connection* Typical Capacity
m3/hr at 500mbg
Typical Capacity
m3/hr at 1000mbg
Blower application
80mm 3″ BSP 850 1100  HRBV, HR Size 10 & 11
100mm 4″ BSP 1300 1700  HR Size 12, 13, 20 & 21
125mm 5″ BSP 2000 2700  HR Size 22, 23 & 31
150mm 6″ BSP 2900 3800  HR Size 32, 33, 41, 42 & 43

*Optional BS404: NP10 flange connection available to order.

Download Data Sheet

Valves for HRBV (RBTM) truck mount blowers

We supply the 80 mm valve for our HRBV blowers with a factory pre-set relief pressure of up to 1240 mbar or to your specification. A 3″ to 2″ BSP adaptor may also be required for this application.

Valves for HR Rotary lobe blowers

The valve size required will vary with the blower size (see table above). Factory pre-set relief pressures of up to 1140 mbar are available, as required.

Vacuum relief valves

Coming soon: We will soon be able to supply relief valves for use with our high vacuum range of blowers.