Pressure reducing valve with shut off

A pressure reducing valve comprising:

• (a) a valve assembly defining a flow path from an inlet to an outlet;
• (b) a throttling arrangement forming part of said flow path, said throttling arrangement comprising a displaceable throttling element displaceable between a fully-open position in which said flow path is open and a closed position in which said flow path is substantially blocked;
• (c) a spring acting to displace said displaceable throttling element to said fully-open position;
• (d) a control chamber including at least one pressure-actuated surface mechanically associated with said displaceable throttling element such that pressure within said control chamber acts to displace said displaceable throttling element against said spring towards said closed position;
• and
• (e) a switchable hydraulic control circuit in fluid connection with said inlet, said outlet and said control chamber, said switchable hydraulic control circuit assuming:
• (i) a first state in which a pressure within said control chamber is equalized with an outlet pressure, and
• (ii) a second state in which the pressure within said control chamber is equalized with an inlet pressure.