Automatic device of adjustment for the no-load of similar compressors etmachines
FRENCH REPUBLIC Industry and commerce On PROBLEMS PATENT Gr. 5.-α. 3. [...] 1.142.179 Service Je the INTELLECTUAL INDUSTRIELLE International Classification: An automatic adjustment for unloaded operation of compressors and like machines. Society said: Ditta Ing. G.[...] (S. P. A.) residing in Italy. Demanded 28 February 1956, to 16m .-Issued 25 March 1957 Published 13 September 1957. The present invention relates to a device automatic adjustment for operation to vacuum of compressors and like machines. Are known adjusting devices for vacuum compressors, for suppressing the operation- member when the pressure reaches a value [...] - completed in the reservoir and delivering the-although highly intangible in operation when the pressure needs Anticipated Results Non Lead below a predetermined value, -ordinary stands close to the value of the pressure maximum. Such devices, controlled by counterweights or load springs calibrated, act in the they send a pressure pulse to a auxiliary cylinder for maintaining the valve is the suction valves of the compressor open. Counterweight devices or springs have the defect that they do not always function measurements- heating, due to wear and sometimes breakage springs and the movement of the counterweight, and because they have a low sensitivity. The device according to the invention remedies these disadvantages; it is essentially wherein comprising an element pitch control- sage of the gas to the closure-the suction valve, which is actuated by a piston differential on the smallest surface of which the tank pressure and acts on the larger at- face which a lower pressure, constant, derived from the charge reservoir in no- health with a pressure reducer, to movement of the piston in the direction of the idling when the pressure in the reservoir exceeds the maximum value pre- sight defined by the value of the reduced pressure by the ratio of the piston surfaces and to obtain the movement of the piston in the opposite direction, by the operation of the compressor, during- the mission that prevailing in the tank is lower- means to said maximum pressure. One embodiment of the device of the inven- is represented, by way of non-limiting example, at the sole figure attached drawing which is a side elevation, cross-section portion. A The body of the device has two co-axial cylindrical bores of different diameters 1 and 2, in which a free differential piston 3 slides sealingly. The end of the smaller bore 2 is communicated, through the connection 4, with the pressure vessel (not shown). The end of the bore of large section 1 pine is brought into communication with the outlet 5 of a pressure reducer 6 of conventional type, whose input 7 is connected, through the conduit 8, with the pressure vessel. An annular groove 9, provided in the smaller cylindrical bore, communicates with the channel 10 and, thereby, with the conduits 11 to pressurize the cylinders of opening of the suction valves of the compressor (not shown). The portion of larger section of the differential piston 3 has, in turn, a groove 12 for cooperating with the groove Maneuverable A sealing member 16 provides the communication of the duct of arrival of the pressurised air from the reservoir with the channel 10. The device operates as follows: When the pressure in the tank is lower than the predetermined limit, the piston 3 is in the position shown the pattern (right-most), so that communication of the reservoir with the conduit 10 is cut off and that, therefore, the suction valves of the compressor are regularly used. In this position, the annular groove 12 of the piston is situated in correspondence with the port 16B, which place the channel 10 in communication with the cylinder 1. A second port 17 contacting the cylinder 1 in communication with the conduit 15 has the role of urging the pipes II to suction by the groove 12 and, therefore, of discharging the idling operation of the com- pressure. The position of the piston 3 is maintained by the constant pressure, independent, in the reservoir, diverted from the reactor 6 acting on the larger surface of the piston. When the pressure prevailing in the charge reservoir reaches the predetermined maximum value, are produced on the smallest surface area of the piston a load slightly larger than that determined by the counter pressure provided by the [...] 6 and, as a result, the piston moves to the left. The groove 12 of the piston 3 beyond the position of the ports 16 and 17 which are blindfolded and closed by the solid portion of the piston. At the same time, the right end of the piston 3 uncovers the groove This things lasts until the pressure in the reservoir has not Left to the point where, the back pressure prevailing downstream of the reducer 6 is still predominant, the piston moves sharply to the right, by restoring the initial conditions of normal operation. The pressure downstream of the reduction gearing can be adjusted by means of the adjusting screw 17B, which in practice corresponds to the variation of the maximum pressure admitted into the reservoir. The above device allows, due to its sensitivity, maintain very small pressure variations in the charge reservoir (deviations, which may be reduced to a fraction of atmosphere). The rapidity of the movement of the piston allows for charging and discharging proximity to the locking cylinder suction valves, by avoiding possible phase uncertainty that may compromise same duration of the suction valves. The device is completed by the needle valve 13, for adjusting the flow rate of the pressure reducer. The valve 16 causes the pressurized reservoir in communication with the shut-off means for the suction valves even when the maximum pressure is not reached: this permits spacercraft the compressor activated even with the pressure vessel, so as only to the compressor under load that, when it reaches the number of revolutions of speed. Various modifications may be made to the device without departing from the scope of the invention. SUMMARY An automatic adjustment for unloaded operation of compressors and like machines, characterized particularly by the following features, considered separately or in combination: c. The piston closes during its movement the communication of the pressurized gas with the closure devices used and the suction valve thereof in communication with the outside or to the suction of the compressor, while, in the motion in the opposite direction, it closes the discharge closure devices used and thereof in communication with the pressurized gas contained in the reservoir; /. The discharge port communicates with the suction of the compressor; Said Society: Ditta [...]. g. [...] fS. r. A.), For [...] : René [...]. For the Ministry