Abstract: A method of uniformly or substantially uniformly heating at least one surface of a substrate, comprises the steps of supporting a substrate, generating a heated air flow, directing the heated air flow to heat a strip of a first surface of the substrate, and moving the flow path of the heated air in a direction transverse to the direction in which the heated air flow impinges on the substrate until the temperature of the whole or substantially the whole first surface of the substrate has been uniformly or substantially uniformly raised. Apparatus for performing this method is also disclosed.

Abstract: A method of uniformly or substantially uniformly heating at least one surface of a substrate, comprises the steps of supporting a substrate, generating a heated air flow, directing the heated air flow to heat a strip of a first surface of the substrate, and moving the flow path of the heated air in a direction transverse to the direction in which the heated air flow impinges on the substrate until the temperature of the whole or substantially the whole first surface of the substrate has been uniformly or substantially uniformly raised. Apparatus for performing this method is also disclosed.

Abstract: A line, especially for delivery of liquefied gas at ambient temperature, has two solenoid valves connected in series with an intermediate section of the line between them. In normal operation when both valves are closed, the isolated intermediate section contains liquid which absorbs heat from the atmosphere and/or from a heater, and the resulting increase in pressure is detected by a pressure sensor. If either valve fails to close fully to shut off flow, the intermediate section is not then isolated, so the absence of a signal from the sensor (the valves being set to close fully) indicates that at least one of them has not properly closed, and an alarm is given.

Abstract: An engine system of the reciprocating or rotating piston type has a device such as a pressure transducer for providing an indication of when combustion of fuel takes place in the engine. The signal provided by the device over a combustion cycle is stored in a memory and compared with a signal provided in a following cycle to provide a more positive indication of when in the cycle, combustion of fuel starts.

Abstract: A fuel injection pumping apparatus includes a piston movable to displace a pumping plunger to deliver fuel through an outlet. Fuel can be supplied to the bore containing the plunger from a pressure source. The piston is moved by liquid under pressure delivered by a cam actuated piston the liquid flowing into the cylinder containing the piston by way of a non-return valve. A spill port is provided to allow surplus liquid to escape from the cylinder. Following movement of the piston by the cam movement of the piston is initiated by closure of a valve. The same valve is utilized to control the return motion of the plunger after the delivery of fuel has stopped.

Abstract: A fuel injection system includes first and second pistons slidable within respective cylinders, the second piston being of larger diameter than the first, first valve means through which fuel at high pressure can be admitted to one end of the second cylinder to act on the piston and second valve means through which fuel can be returned from the one end of the first cylinder to the one end of the second cylinder and a third piston which is subjected to fuel at high pressure for returning the first and second pistons towards the one end of the second cylinder when the first valve means is closed and the second valve means is opened. When the first valve means is opened and the second valve means closed, fuel at injection pressure is displaced from the one end of the first cylinder and is supplied to a fuel injection nozzle for supply to an associated engine.

Abstract: A fuel injection pumping apparatus comprises a displacement piston which is located within the cylinder, an outlet from one end of the cylinder and a fluid pressure operable member mounted within a further cylinder for actuating the piston and causing fuel to be delivered through the outlet. Means is operable upon movement of the displacement piston to a predetermined position to terminate delivery of fuel through the outlet and valve means is provided to control the application of fluid under pressure to the fluid pressure operable member.

Abstract: A device for indicating changes in the specific gravity of a liquid comprises first and second floats adapted to float on the surface of the liquid, the float having different shapes and/or densities so that the depth of the floats in the liquid varies in accordance with the specific gravity of the liquid and means for producing an electrical signal dependent upon the depth to which the floats are immersed relative to one another.

Abstract: A fuel injection system for supplying fuel to a combustion space of an internal combustion engine includes a nozzle having a valve member urged to the closed position by fluid under pressure derived from an accumulator. A displacement piston is movable to supply fuel under pressure to the nozzle upon opening of a solenoid operable valve and return motion of the piston is effected by closing the valve and opening a further solenoid operated valve. The return motion of the piston is achieved by fuel under pressure supplied to one end of the cylinder containing the piston.

Abstract: A fuel injection system for supplying fuel to an internal combustion engine includes a displacement piston which can be moved to displace fuel through a valve controlled outlet. The piston can contact the valve to prevent further flow of fuel through the outlet and the valve during continued movement of the displacement piston can contact a push rod which in turn can exert a force on a stepped valve member to close the valve member to prevent flow of fuel from said outlet through spray orifices.

Abstract: A fuel injection system includes a piston movable within a bore to displace fuel through a fuel outlet. Fluid under pressure can be admitted to the other end of the bore by way of a valve means to effect movement of the piston to displace fuel and when the valve means is closed a further valve means can be opened to permit the piston to move in the opposite direction. The valve means and the further valve means are actuated by a control pressure generated by a stack of piezo-electric crystals. The valve means 23 includes a plurality of pressure balanced pistons and when the stack of crystals is de-energised the valve means is in the closed position.

Abstract: A distributor type fuel injection pump includes an injection pump to which fuel is supplied from one end of a bore accommodating a slidable shuttle. The shuttle is moved towards the one end of the bore during the filling strokes of the injection pump by way of a first valve means and is allowed to move away from said one end of the bore during an interval between the filling strokes of the injection pump by fuel under pressure derived from the outlet of a feed pump by way of a second valve means. An electrically operable valve is provided to limit the amount of fuel which can flow from said other end of the bore and a sensor is provided to detect the position of the shuttle within the bore and which by way of a control circuit actuates said electrically operable valve. A third valve means is provided to admit fluid under pressure to said other end of the bore when it is required to fill the injection pump.