Abstract: A fluid-working machine has a working chamber of cyclically varying volume, high and low pressure manifolds, and high and low pressure valves for regulating the flow of fluid between the working chamber and the high and low pressure manifolds respectively. A controller actively controls at least one said valve to determine the net displacement of working fluid of the working chamber on a cycle by cycle basis. At least one said valve is a variable timing valve and the controller causes the valve to open or close at a time determined taking into account one or more properties of the performance of the fluid working machine measured during an earlier cycle of working chamber volume.

Abstract: Methods and apparatus for converting energy from a stream of compressed gas into mechanical work as systems incorporating such methods and apparatus.

Abstract: A method of measuring a property of entrained gas in a hydraulic liquid received by a working chamber of a fluid working motor, wherein the said property is determined from the period of time elapsing between the closure of a first valve to isolate the working chamber and the passive opening of a second valve to bring the working chamber into fluid communication with a manifold. The property may, for example, be related to the concentration of entrained gas in the received hydraulic liquid or the compressibility or bulk modulus of the received hydraulic fluid.

Abstract: A system to provide mechanical energy to well-head equipment by directing pressurized gas existing in nearby pipelines to an engine. The engine is a linearly reciprocating piston in a closed cylinder driven by pressure differentials between the gas on either side of its piston, the differential being controlled by a switching valve which directs higher and lower pressured gas to the appropriate side of the piston, and which recirculates spent gas from the lower pressure side of the piston back to the pipeline. The system is a closed system, and avoids venting or flaring gas used in the engine.

Abstract: A safety shutdown circuit for a pneumatic pump system. The pump system includes a manifold assembly for discharging pumped liquid. The liquid is discharged from the system by a reciprocating piston apparatus which drives a liquid pump cylinder. The pump system is provided with a pneumatic safety circuit for monitoring the stroke time or rate of the reciprocating air cylinder. The safety circuit includes a safety shutdown valve and a pneumatic timer associated with the shutdown valve. The pneumatic timer vents air supply within the safety circuit after a predetermined time interval. If a leak or failure occurs in the pump system, the reciprocating piston apparatus will complete a stroke in less time than the predetermined time as a result of the pressure loss incident to the leak or failure. In such event, the air supply within the safety circuit is directed through the shutdown valve to the pump system START valve to deactivate the system.

Abstract: A forging hammer employs compressible fluid to drive the ram into impact and a trapped volume of compressible fluid to cause the ram to be retracted from impact position when fluid driving the ram into impact is released. The velocity of impact is adjusted by the timing of the opening of a valve allowing variable amounts of compressible fluid into a cylinder from a compressible fluid supply. Pressure sensing means is provided to sense the pressure of the lifting fluid, calculating means for calculating kinetic energy from the rate of change of lifting air pressure, comparator means for comparing kinetic energy with a standard and a counter for accumulating error. Sensing the rate of change of pressure of the lifting fluid permits calculation of the velocity of the hammer. Kinetic energy at the time of impact is calculated from the velocity and the mass of the ram assembly.

Abstract: A forging hammer employs compressible fluid to drive the ram into impact and a trapped volume of compressible fluid to cause the ram to be retracted from impact position when fluid driving the ram into impact is released. The velocity of impact is adjusted by the timing of the opening of a valve allowing variable amounts of compressed fluid into a cylinder from a compressible fluid supply. As the ram is driven into impact, the compressible fluid which causes the ram to be retracted is compressed and increases in pressure. The peak of pressure in this trapped volume of compressible fluid is sensed and compared with a peak value of reference pressure which represents a desired impact energy. If there is an error between the measured peak and the desired peak effect, an incrementing or decrementing signal is provided to correct the valve to adjust the effect of the next blow.

Abstract: A forging hammer employs compressible fluid to drive the ram into impact and a trapped volume of compressible fluid to cause the ram to be retracted from impact position when fluid driving the ram into impact is released. The velocity of impact is adjusted by the timing of the opening of a valve allowing variable amounts of compressible fluid into a cylinder from a compressible fluid supply. Historical data is accumulated on a given forging hammer correlating the peak lifting fluid pressure with ram stroke. Thereafter, it is possible by measuring lifting fluid pressure and obtaining the peak value to determine the stroke by comparing the measured value against compiled pressure vs. stroke data for various residual lifting air pressures. Knowing the dimensions of dies and other structures employed with a forging hammer, it is then possible to calculate the rate of deformation from the forging size of the previous blow and the forging size of the current blow.

Abstract: A controller and method are provided for controlling pneumatic presses, and similar machines. The controller comprises a gauge to measure increments of stock length passing through the press, a length recorder to set the desired piece length, and a length comparator which compares the readout of the gauge with the preset recorder piece length, and when equal, generates a stroke initiate signal. The stroke initiate signal opens an air valve portion of the pneumatic press to communicate pressurized air with the power side of an air actuated ram, which in turn converges the press platens to perform the desired press function, such as punching holes, notching, cutoff, or the like. The controller also includes a timer to measure time beginning from the stroke initiate signal, a time recorder to set the time the air valve is to remain open, and a time comparator which compares the readout of the timer with the preset valve open time, and when equal, generates a stroke halt signal.

Abstract: A steam engine wherein the inlet and relief valves are subjected to balanced stresses and the pressure of steam is maintained above the critical point. The engine can be braked electrically, mechanically and with steam; the braking with steam takes place subsequent to the application of electrical and mechanical brakes. The engine is equipped with arrangements for venting the steam path prior to starting, for replenishing the supply of fluid in order to compensate for leakage through the valves and/or from the engine cylinders, and with a control system which partly opens the relief valves and closes the inlet valves in response to actuation of the steam brake.

Abstract: A uniflow steam engine of the multi-cylinder type wherein the cylinders are rotatably mounted within a jacket having a sinusoidal cam track therein. Extending through slots, the ends of which are the exhaust ports in the cylinders and into the cam track are cam followers which are mounted on the pistons for reciprocable movement therewith. At the head end of the cylinders there are apertures which rotate with registered cutouts in superimposed valve rings that control the flow of steam from manifolds at the head ends of each of the cylinders into the cylinders as the cylinders rotate. By adjusting the relative position between the valve rings, the length of time of steam introduced on each cycle may be adjusted and by concomitantly rotating both valve rings, the initial time for introduction of steam may be adjusted to alter lead or reverse torque.