FUEL INTERCEPTION VALVE WITH POSITIVE ACTION, APPROVED AND CALIBRATED INAIL (EX ISPESL)
The advantages off ered by using fuel interception valves are considerably greater than those for thermal discharge valves, as defi ned in the Standard Index denominated “ R “ which, when the request for fuel interception valve is indicated, confirms the alternative possibility to use the thermal discharge valve (self-activating valve, with positive safety, where the shutter opens due to the excessive high temperature and closes again when it decreases. This means that an amount of the produced heat is transferred to the outside, by the discharge of water, in order to reach the preset temperature limit of the same water).
The most signifi cant advantages are outlined as follows:
• Installation is far easier (the thermal discharge valve is in fact also connected to a solenoid fuel valve and /or a valve that allows the reinstatement of the discharged fluid).
• When a thermal discharge valve is foreseen “with reinstatement” when operating the introduction of cold water causes drawbacks to the generator (thermal shock).
• When the thermal discharge valve is foreseen “without-reinstatement” when operating the amount of discharged fluid can, in most cases, flood the boiler room.
• The interception valve makes it easier for the plant designer to choose, as the sizing is per formed entirely according to the sizes of the fuel adduction pipes.
• The fuel interception valve is also a much cheaper solution.
The valve consists in two parts:
• The body of the valve through which the liquid or gas fuel flows.
• The control device fi tted with a sensitive (diathermic fluid) element.
• The valve shutter rod is connected to the control device so the valve can be closed (blocked) when:
• a) the temperature of the generator exceeds the set value;
• b) there is a leak of diathermic liquid (positive action).
In the case of a block, the valve closes and can only be operated by manual intervention.
This operation can occur when the temperature of the heat generator decreases below 87°C.
The positive action occurs whatever the temperature of the sensitive element.
Under normal conditions (temperature less than 97°C) the rod (4) rests on the control piston (6) and the valve remains open.
If the piston moves to the left due to the expansion of the fluid content in the sensitive element (9) it will cause the valve to close instantly.
If the piston moves to the right due to a leak of fluid from the capillary (breakage) it will cause the valve to close instantly.
To perform manual resetting (when the temperature decreases below 87°C) use the reset latch (1).
The valve is patented and totally conforms to all INAIL (ex ISPESL- National Institute for prevention and safety) Standards and Specifi cations (Appendix 3)
• Valve body and the control device in forged and chromed brass CW617N
• Bellow in phosphorous bronze
• Copper capillary and probe (length 5m)
• Stainless steel control rod
• O-ring seal ring in nitrilic rubber
• Steel springs
• Other details in brass CW614N