Abstract: A safety valve has a housing with an inlet, outlet and a threaded opening carrying a walled unit which is sealingly removable from the housing; the portion of the unit extending into the housing is apertured to permit flow and has a valve seat and co-operating plate to which is attached a valve stem extending through an annular diaphragm in secured relationship. The diaphragm is supported by the housing and in the portion of the unit exterior of the housing is a biasing device which acts on the diaphragm.

Abstract: An adjustment control for a thermostatic valve consists of a non-rotatable component to the valve on which is mounted a rotatable knob for setting the temperature control, the knob having a maximum rotation of about one revolution. A releasable auxiliary device is provided which is operable between the component and the knob at a predetermined intermediate rotational position of the knob to limit the rotation of the latter.

Abstract: A differential pressure relief valve formed of a housing having first and second chambers sealed from the atmosphere and separated by an annular diaphragm with the chambers and the annulus of the diaphragm traversed by a moveable sleeve. The first chamber communicates to a primary pressure source through a first channel in the housing and the second chamber communicates to a secondary pressure source through holes provided in the sleeve and then to a second channel in the housing. The end of the sleeve protruding from the second chamber is engageable with a seat in the housing. The arrangement is such that when the primary pressure exceeds the secondary pressure by a predetermined amount, the end of the sleeve protruding from the second chamber engages the seat but if the primary pressure does not exceed the secondary pressure by the predetermined amount, the end of the sleeve does not engage the seat, and fluid escapes from the source through the second channel and communicating sleeve, past the seat.

Abstract: A balanced valve disc and seat structure has a hollow valve disc engageable with the seat and pressure responsive means supported in the disc; the pressure responsive means divides the hollow valve disc into separate first and second chambers with a first aperture in the disc communicating with the first chamber and a second aperture in the disc communicating with the second chamber. A plunger has one end secured to the pressure responsive means with the other end of the plunger extending through the second chamber and the valve seat with means engaging the other end of the plunger when the first chamber has a higher pressure than the second chamber.

Abstract: A thermostatically controlled valve for heated fluid flowing through a conduit has a valve seat and cooperating valve mechanism to permit the flow of fluid through the seat; a housing, open at one end, is secured to the conduit at the other end over the valve mechanism. A sensor, secured in the open end of the housing, is responsive to change in ambient temperature of the air above the housing and the sensor operates a plunger which acts on the valve mechanism to regulate the flow through the said seat. Thermal shielding means are provided in the housing between the sensor and the valve mechanism to prevent heat from the latter affecting the sensor and vents are provided in the housing below the thermal shielding means to allow air heated by the valve mechanism to escape to atmosphere.

Abstract: A first and second check valve operated independently in a conduit section and having first and second valve stems on a common axis with first and second valve seats and cooperating normally disposed valve plates with the valve stems inclined away from the direction of flow, the second valve seat being larger than the first valve seat and the lowermost level of the second valve seat is at least below the lowermost level of the lift of the first valve plate with a single removable cover on the conduit section for securing the check valve in position.

Abstract: A thermostatic control valve for regulating the supply of fluid through a conduit includes in combination a valve plate and seat in the conduit, the valve plate having a valve stem extending outwards of the conduit with the valve stem having a spring exterior of the conduit to move the plate away from the seat and a housing secured to the conduit with a retractable plunger in the housing operative on the valve stem. The plunger is contained in a casing having means responsive to temperature change to move the plunger towards the seat. An interior member is threaded in the housing and removable means are used for attachment to the interior member to rotate it in the housing, thus providing adjustment. The control valve is secured to the conduit through a washer having a pawl which engages with ratchet shaped teeth of a ring secured in the control valve.

Abstract: A thermostatic valve has a working element, a valve seat and a guide member for the working element below the valve seat; the guide member is connected to the valve seat through a plurality of holding arms, each supported by a yoke arm connected above the valve seat. The guide member has a plurality of slots on its underside and each of the holding arms at its free end has an inwardly extending claw engageable with one of the slots to secure the guide member to the valve.

Abstract: A differential pressure overflow valve has a housing with a differential pressure indicator therein consisting of a cylinder containing a piston moving against the force of a spring; the piston is spaced from said cylinder to provide an annular gap. The housing also has an inlet and an outlet pressure chamber; the inlet pressure chamber is connected by a passage to one end of the cylinder and the outlet chamber by another passage to the other end of the cylinder. To provide a choke effect the cross sectional area of the annular gap is substantially smaller than the cross sectional area of the connecting passages.

Abstract: A radiator valve has a housing carrying a valve stem with plate and loading spring on the valve stem above the valve plate; a first seal bears against the valve stem between the valve plate and the spring. A presetting member is located in the housing and it carries a second seal bearing against the valve stem at a position removed from the valve plate with respect to the first seal.

Abstract: A control unit is formed of a housing containing a filter with an inlet and outlet in line above the filter, the latter forming a channel with the housing; a pressure reducer is positioned between the inlet and the outlet above the filter. A rotary valve positioned between the filter and the pressure reducer reverses the flow in the unit. A plug-valve is located in the housing to provide drainage and the plug-valve is connected to the rotary valve so that on reversal of flow, the plug-valve opens to drain the unit.

Abstract: A filler fitting for heating installations has a housing with an inlet, an outlet and between them a pressure-reducer having a valve mechanism which includes a valve stem spring loaded to an open position; to facilitate filling a releasable pin is provided which acts on the valve stem by means of a lifting cam located outside the housing. The cam is also capable of rotation and the pin can thereby act to adjust the spring pressure on the valve mechanism independently of the action of the pin on the valve stem.

Abstract: A valve structure has a body with an inlet, an outlet and an intermediate by pass aperture. A pair of identical check valves are located in the body, one to each side of the aperture. The check valve nearest the inlet has a slidable housing, movable to cover the aperture, biased away from the fixed housing of the second check valve by a spring. The check valves are closable by individual springs in the direction of the inlet but the individual springs are stronger than the spring separating the housings.

Abstract: A back flow preventer valve has an annular resilient diaphragm secured to the valve body between the inlet and outlet valves; the diaphragm supports an annular wall member which closes off a vent. In the event of back flow, the pressure on the membrane raises the annular wall from the vent to open the latter and the back flow does not cause contamination. The feature of the valve is a seal formed by the valve body and the annular wall engaging in the event of diaphragm failure, thus ensuring that the back flow travels through the vent.