Abstract: The invention relates to a control for heat recovery (WRG) in a compressor system with liquid injection comprising a fluid circuit of the fluid which is to be injected with control valve, this fluid passing through at least one heat exchanger with control valve to the WRG and upstream of the compressor (13) of the compressor system there being a compressor-side control valve (6) and downstream of the heat exchanger (9) of the WRG there being a WRG-side control valve (7), one electronic control unit (11) controlling at least one of these control valves (6 and/or 7) by means of an algorithm, and the required temperatures for the mass flows [4, 5] of the WRG being able to be input as parameters into the control unit [11].

Abstract: A modular system for the control of at least one compression system for the compression a fluid medium, said compression system comprising compressors (C1-C7) and their controllers (A1-A7) for the compression of the fluid medium, secondary treatment devices for the treatment of the medium delivered from the compressors, and piping systems (17-19, 23) for conducting the fluid medium to a place of consumption (16, 22), said control system comprising a control unit (3) containing a data processing system (34) for controlling the compression system, a user interface (35) including a display associated with it and transmission means for the transmission of control data between the control unit, the controllers and pressure sensors. The transmission means consist of data communication buses, preferably serial communication buses (30-32) and a data communication port unit (33) serving to connect the bus to the control unit (34). The controllers and pressure sensors are connected to common data communication buses.

Abstract: In a lubricant-cooled gas compressor (10) the temperature of separated lubricant returned to the air-side (11) is monitored by a thermostatically controlled restrictor valve (22) which minimises the flow of returned lubricant when temperature is low as on start up or when running on reduced load but increases the flow as the lubricant temperature increases. This will minimise he condensation of water from indrawn air when the temperature of the compressed air is too low to retain the water as vapour, so that the returned lubricant is contaminated with water which will damage the moving components of the air-end.

Abstract: The invention relates to the use of variable speed control of the cooling fan on a variable speed oil-injected screw compressor. A screw compressor (11) comprises at least one stage of compression, each with a pair of rotors, variable speed compressor drive means (12), an oil reclaimer (13) from the compressed air and cooling apparatus (17) for cooling the oil extracted from the compressed air. The cooling apparatus comprises a heat exchange device and a fan (18) driven by a motor (19) which can be run at different speeds.

Abstract: A piston sealing ring assembly (70) for sealing the piston/cylinder interface of a double-acting gas compressor including a first and second cut piston sealing ring (54,72) each bounded by first and second planar surfaces (6,8), the first piston sealing ring (54) having an overlapped cut with generally circumferentially extending inner and outer overlapping portions (56,58) which contact each other to form a continuous seal extending from the first surface (6) to the second surface (8) of the first piston sealing ring (52) and separating an inner ring gap (62) from an outer ring gap (64). The periphery of the outer ring gap (64) of the first piston sealing ring (54) at the first surface (6) is sealed by the second surface (8) of the second piston sealing ring (72). The second piston sealing ring (72) is similarly disposed in relation to the first piston sealing ring (54) so its outer ring gap (64) is sealed at the second surface (8) by the first surface (6) of the first piston sealing ring (54).

Abstract: An air compressor includes a stator, which includes an inlet and an outlet and defines a substantially cylindrical bore, and a rotor eccentrically rotatably mounted in the bore. The rotor is connected to be rotated by a three-phase asynchronous electric motor of pole amplitude modulated type which is switchable between low speed six pole operation and high speed four pole operation under the control of a controller. A pressure sensor communicates with the compressor outlet and is connected to the controller which is arranged to produce a first signal when the compressor discharge pressure falls below a first threshold value and a second signal when this pressure rises above a second threshold value.

Abstract: A regenerative rotodynamic compressor has a stator which defines, together with the periphery of an impeller, an annular flow channel of circular cross-section within which is a core ring having a circular cross-section coaxial with and of a diameter at least half the diameter of the flow channel cross-section. The impeller has a ring of curve aerodynamic blades around its periphery that project laterally into the flow channel up to the core ring. The stator, the impeller and blading, and the core ring are all made as die-cast components, the stator being divided on a stepped radial plane so as to the assemblable from two main die cast components and an insert ring, also die-cast, that in part defines the flow channel and is fitted between the two main components, being secured to one of them. Inwardly directed radial pegs on the core ring locate it in the flow channel by being clamped between the insert ring and the main stator component to which it is secured.

Abstract: A scanning gauge and scanning method are disclosed for measuring the effective open area of a throat formed between adjacent vanes secured together at their ends by buttresses or the like wherein locators are mounted on an elongated guide assembly for engaging the vanes forming the throat, a scan element is arranged for traversing the elongated guide assembly in longitudinal movement along the radial length of the throat for assessing radial length thereof, a sensor head is supported by a floating mount on the scan element to remain in engagement with the trailing edge of one vane and a convex surface of the adjacent vane during sweeping movement of the scan element about an axis generally parallel to the trailing edge of the one van for assessing the shortest opening dimension at various sections along the length of the throat, longitudinal and sweeping movement of the scan element being effected by a longitudinal stepper motor and a sweep motor each including mechanical limit switches for monitoring and reg

Abstract: A safety valve comprises a valve member which is movable against spring biasing force to close under a predetermined flow rate against valve seats and allow only a small bleed through the valve via slots. The housing consists of two parts which are adjustably connected together by a screw thread which includes a locking nut enabling the valve to be adjusted and set for operation over a range of different flow rates.

Abstract: A screw rotor machine for compressing air or other working fluid comprises a housing including two intersecting bores axes which together define a working space. The pair of intermeshing rotors are rotatably mounted one in each bore. The rotors have helical lands and intervening grooves whereby rotation of the rotors in connecting engagement is effective to compress the working fluid (or to expand the fluid if the machine is used as an expander). A low pressure port and a high pressure port formed in the housing at opposite ends thereof permits inlet and outlet of the working fluid. The grooves of the rotors each have a primary flank and a secondary flank. The tips of the primary flanks of both the male and female rotors are formed by parabolic arcs which generate major portions of one of the flanks of the opposite rotors. A major portion of the secondary flank of the female rotor is also a parabolic arc.

Abstract: A tool has a housing, a reversible fluid-pressure operated rotary motor which is arranged to drive a bit holder via reduction gear boxes and a clutch which is designed to slip at a predetermined torque. When a trigger is pressed, pressure air is delivered via a valve to the motor, and in a first position of the valve the motor is driven in a forward direction. When the predetermined torque is reached, the clutch slips and displaces an actuator which opens another valve. This in turn creates a pressure differential across the valve which causes it to move to its second position in which pressure air is delivered to the motor to drive it in the reverse direction. When the trigger is released, the valves return to their original positions.

Abstract: A pneumatic timer has a cylinder (3) containing a piston (4), which is movable upwards and downwards to vary the volume of a chamber (11) below the piston by means of a screw-threaded spindle (7) and a screw-threaded sleeve (9) which is rotatable by a knob (10). Air is supplied to the chamber (11) via an inlet (26) and a long spiral groove (17, FIG. 2) formed in a disc (14), which is incorporated in the piston (4). When the air pressure in the chamber (11) reaches a predetermined value, the valve (5) is actuated by a diaphragm (12) and the time taken for this to happen from initiation of the air supply is varied by moving the piston (4) to alter the volume of the chamber (11). The air flow into the chamber (11) is accurately metered by the groove (17) and may be made much smaller than that through a variable orifice as is done in existing pneumatic timers. The timer is accordingly more accurate and provides longer time intervals than can existing timers of a similar size.

Abstract: A classification instrument adapted for accurately measuring both blocked and open flow area for airfoil or vane elements such as turbine stator vanes having mounting buttresses at each end includes stops for mounting the vane element upon the instrument in a predetermined position established by a plurality of datum points or lines corresponding to the various stops, a plurality of indicators for measuring various points and surfaces upon the vane and providing classification readings from which the open and closed area values for the vane may be determined. A method is also disclosed for classifying or determining the blocked and open areas for such air foil or vane elements.

Abstract: A lung ventilator which changes over automatically to provide either ventilation or to allow for natural breathing has an oxygen inlet (1) connected through a pressure regulator (2) and a flow regulator (4) to a reservoir (7). A secondary supply to the reservoir (7) takes place through a NOT unit (10). Oxygen from the reservoir (7) is supplied to a face mask connection (29) either through a demand valve (34) or through a second flow regulator (18) and a spool valve (26). The spool valve (26) is controlled by a pneumatic timing system (20-25) and the oxygen from the reservoir either flows intermittently through the spool valve (26) which is opened and closed by the timing system to provide ventilation or, it is supplied through the demand valve (34). Changeover from one supply to the other and back again is controlled in dependence upon the pressure in the reservoir (7).

Abstract: In a regenerative rotodynamic compressor, a portion of a disc-like impeller adjacent the impeller periphery extends radially through an annular chamber in the compressor casing concentric with the impeller, thereby dividing said chamber into two annular side channels, one on each side of the impeller. The portion of the impeller lying in the annular chamber has scooped out annular cavities or recesses in its sides in which are disposed rings of aerodynamic blades, and fluid flow passing around the annular chamber from an inlet to an outlet is caused to circulate repeatedly, flowing radially outward through the blading in the impeller cavities and radially inward in the annular side channels alongside the impeller outside the impeller cavities. The aerodynamic blades are designed so that the angle between the entry and exit flows of each blade is greater than 90.degree..

Abstract: A classification gauge and method of operation for accurately and repeatably measuring the open flow area of a pair of air foil or vane elements interconnected by end buttresses, the classification gauge including first and second sets of probes arranged for contact with the vanes adjacent the open flow area and first and second lateral probes for engaging the end buttresses, an indicator of open flow area being effectively interconnected with the two sets of probes and the two lateral probes by means of a proportional mechanism.

Abstract: In a regenerative rotodynamic compressor, a portion of a disc-like impeller adjacent the impeller periphery extends radially through an annular chamber in the compressor casing concentric with the impeller, thereby dividing said chamber into two annular side channels, one on each side of the impeller. The portion of the impeller lying in the annular chamber has scooped out annular cavities or recesses in its sides in which are disposed rings of aerodynamic blades, and fluid flow passing around the annular chamber from an inlet to an outlet is caused to circulate repeatedly, flowing radially outward through the blading in the impeller cavities and radially inward in the annular side channels alongside the impeller outside the impeller cavities. Shroud rings at the blade tips form cores around which this circulation takes place. The blades are cast integrally with the impeller disc or with the shroud rings.

Abstract: A compressed-gas-operated reciprocating-piston device, e.g. a concrete breaker, rock drill or chipping hammer, has a cylinder component of composite construction, comprising a rigid inner metal tube in which the piston reciprocates and a moulded outer sleeve of rubber or plastics material, e.g. polyurethane, which surrounds the tube over the majority of its length and is bonded thereto. The sleeve has three integral moulded longitudinal ribs in which are moulded longitudinal passages for transmission of compressed air to the cylinder interior. An outer tubular muffler of rubber or plastics material surrounds the composite cylinder component and defines a sound-reducing path for exhaust gas from the cylinder to the atmosphere. The exhaust gas is discharged into two spaces defined between two pairs of adjacent ribs of the sleeve within the muffler, these two spaces forming part of an expansion chamber in the muffler.

Abstract: A compressed-gas-operated reciprocating-piston device, e.g. a concrete breaker, rock drill or chipping hammer, has a cylinder component of composite construction, comprising a rigid inner metal tube in which the piston reciprocates and a moulded outer sleeve of rubber or plastics material, e.g. polyurethane, which surrounds the tube over the majority of its length and is bonded thereto. The sleeve has three integral moulded longitudinal ribs in which are moulded longitudinal passages for transmission of compressed air to the cylinder interior. An outer tubular muffler of rubber or plastics material surrounds the composite cylinder component and defines a sound-reducing path for exhaust gas from the cylinder to thge atmosphere. The exhaust gas is discharged into spaces defined between adjacent ribs of the sleeve within the muffler, these spaces forming part of an expansion chamber in the muffler.