IL44369A - Fluid pressure boosting system - Google Patents

Description

FLUID PRESSURE BOOSTING SYSTEM Hambert S.A.

The present Invention relates to fluid driven pressure boosting systems.

An object of the present invention is to provide a fluid driven pressure boosting system for maintaining a nearly constant required pressure in a variable consumption delivery manifold, the driven fluid being supplied to the system by a variable pressure source.

To this end the motive fluid pressure is conveniently regulated according to the variations in the pressure of the driven fluid source, this result being obtained by reliable, precise and ^inexpensive means.

A protective device prevents the pressure booster from functioning in the event of cut--off in the supply of driven fluid to the system.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, vrhereln the preferred embodiment of the present invention is clearly shown.

Figure 1 is a connection diagram of a system comprising a pressure booster and a feedback regulator; Figure 2 is a schematic section through an embodiment of a feedbacks regulator; Figure 3 is a connection diagram of a system comprising a pressure booster, a feedback regulator and a protective device; Figure is a schematic section through an embodiment of a protective device.

In the connection diagrams, devices are represented by rectangular blocks identified by appropriate abbreviations, conduits intended foctfluid circulation are represented by full lines provided with arrows showing the direction of the flow, ' and conduits intended for pressure transmission are represented by broken lines, in these connection diagrams a fluid-driven pressure booster is generically represented by a rectangular block identified by the abbreviation PB and provided with four connections, two incoming and two outgoing, identified as follows* MFI is the motive fluid inlet, DFI is the driven fluid inlet, MFO is the motive fluid outlet, and DFO Is the driven fluid outlet.

Preferably, the pressure booster is of the reciprocating doubleacting type. For a good understanding of the invention, it is important to know that, for such a fluid-driven pressure booster in normal working conditions, the pressure PDFO at the driven fluid outlet depends on the pressures PDFI at the driven fluid inlet, P PI at the motive fluid inlet, and PFO at the motive fluid outlet, according to the following formula: PDFO « PDFI + r. (PMFI - PMFO) - DPRS (F) where £, is the transmission ratio of the pressure booster, and DPRS is the pressure drop due to various opposing forces of a mechanical hydraulic nature, The ratio of the volume flow rate QMF of the motive fluid to the volume flow rate QDF of the driven fluid is superior to the transmission ratio £. The above notations will be frequently used hereinafter.

Fluid-driven pressure boosters are well known in the art. A flui driven pressure booster ma consist of a plurality of fluid-driven pressure boosters conveniently combined in series and/o parallel. Hereinafter, the term "pressure booster" will be used to refer to a fluid-driven pressure booster.

The driven fluid is supplied to the system by a driven fluid source at a pressure that may vary in a random fashion; the driven fluid leaving the pressure boosting system is directed towards a manifold delive ing it to the various consumption points; the consumption in this manifold is variable, and a certain level of pressure is required at its entry. In the connection diagrams the source and the delivery manifold for the driven fluid are respectively represented b circles with the abbreviations DFS and DFM.

The motive fluid is supplied to the system by a motive fluid source at a pressure that may vary, provided it remains sufficient for the system*s needsj the motive fluid leaving the system is directed to an exhaust manifold to be either evacuated, recuperated by a pressure generator and sent back to the source, or used in any other fashion* In the connection diagrams, the source of and the exhaust manifold for the motive fluid are represented by circles with the abbreviations MFS and MFM.

The object of regulation is to maintain the driven fluid outlet pressure within close limits of the required level with a minimum consumption of motive power. To this end, according to this invention, the motive fluid is supplied to the pressure booster through a regulating device, which will be called a feedback regulator, which is sensitive to the pressure PDFO and which adjusts the pressure PMFI in accordance with the difference between the pressure PDFO and the required pressure., The feedback regulator comprises means for controlling the pressure of the motive fluid supplied to the pressure booster, consisting preferably of a control valve whose inlet is connected to the motive fluid source and whose outlet is connected to the pressure booster motive fluid inlet. This valve is operated by a control, device which comprises a control element sensitive to the pressure PDFO urging the valve in the closing directio and adjustable opposing means urging the valve in the opening direction. The opposing means is set at a value which will counterbalance the action of pressure PDFO when this pressure is at the required level.

Under these circumstances, the pressure PDFO is maintained within close limits of the reqdred level* Whenever the pressure PDFO is below the required level, the valve moves to open position, thereby bringing an increase of PMFI which results in an increase of PDFO, until PDFO reaches the required level. Whenever the pressure PDFC is above the required level, the valve moves to closed positio thereby bringing a decrease of PMFI which results in a decrease of PDFO, until PDFO reaches the required level. Thus, the pressure PDFO is maintained-within close limits of the required level, whatever be the fluctuations of PDFI or PMFO and the variations of the pressure drop DPRS (which depends on the flow rate)* Figure 1 is a connection diagram of a system comprising \ a. pressure booster PB and feedback regulator FR. The driven fluid source DFS of the pressure booster PB is connected b a conduit 2 to the delivery manifold pl The motive fluid source MFS is connecte by a conduit 3 to the inlet of regulator' FR; the outlet & of regulator FR is connected by a conduit h to the inlet MFI of the pressure booster PB; and the outlet FO of the pressure booster PB is connected by a conduit 5 to the exhaust manifold MFM. A conduit 8 connects conduit 2 to a port h. of regulator FR, to transmit pressure PDFO thereto.

Figure 2 shows an embodiment of a feedback regulator.

A housing 200 is provided with an inlet 201 , an outlet 202 and a port 203 (the ports 201 , 202, 203 must be respectively identified with those marked in f ure 1) a dia hra m 21 ^ movable therein, divides the housing 200 into two independent chambers 221 and 222 to which are exposed the faces 211 and 212 of a valve piston 213j piston face 211 is directed down* wards and piston face 212 is directed Upwards J the chamber 221 communicates with the port 203; thus the pressure PDFO acts Upon piston face 211· The chamber 222 contains means for pro* vidlng an adjustable opposing force consisting of a compression spring ¼1 compressed between piston face 212 and a support 2^2, the position of the support ^ being adjustable by means of a screw 2**3, rotatable by a handle 2 tj a port 2Λ5 puts the chamber 222 in communication with atmosphere* A part of the housing 200 forms the casing of a valve 231 connected to the piston 213 by a rod 210 and adapted to interrupt communication between ports 201 and 202 when applied against its seat 232, The opposing force acting upon piston face 212 urges the valve towards its opeia position (shown in Figure 2)„.: In a system comprising a pressure booster and a regulator* an unexpected interruption in the supply of driven fluid at the pressure booster inlet could have harmful consequences* if, for example, the inlet conduit is put into communication with the atmosphere, the pressure booster will deliver air under pressure to the delivery manifold* Ifon the contrary the inlet conduit is cut of from the atmosphere and consumption of fluid in the delivery manifold is continued, the combined action of the regulator and the pressure booster will cause suction in the driven fluid inlet conduit that could lead to a high degree of vacuum (if the driven fluid is a gas) or cavitation (if the driven fluid Is a liquid) ., In the usual case wherein /the minimum pressure of the driven fluid at the driven fluid inlet is known to be higher than atmospheric pressure,.; the harmful consequences . V of an Interruption in the supply of driven fluid may be avoided byi us ing a protective device that will shut the pressure booster down when the pressure at the driven fluid inlet becomes abnormally low and will keep it out of action until said pressure, becomes normal again, The level below which the inlet pressure is considered abnormally low will be called critical level.

In its preferred form, the protective device is sensitive to the pressure PDFI and , when this pressure drops below the critical level, it interrupts the flow of motive fluid to the pressure booster and causes dissipation of the pressure of motive fluid at the pressure booster inlet. Figure 3 is a connection diagram of a syistem comprising a pressure booster PB, a feedback regulator FR and such a protective device DB.

Besides the elements already shown in Figure 1 , it may be seen that the conduit * connecting the outlet jg, of the regulator to the inlet MFI of the pressure booster PB comprises two portions and the outlet of the regulator is connected by portion ½, to the inlet β of the protective device DB; the outlet £ o the protective device DB is connected by portion to the inlet MFI of the pressure booster PB; and a conduit 10 connects conduit 1 to a port g. of the protective device DB, to transmit the pressure PDFI thereto. Figure k shows an embodiment of such a protective device in which a housing 00 is provided with a inlet 501 , an outlet 502, a discharge port 0 and a port 503 (the ports 501, 502, 03 must be respectively identified with those marked a, £, σ. in figure 3) ; a piston 510, movable therein divides the housing 500 into two independent chambers 521 and 522 to which faces 511 and 512 on the piston 1 are exposed; and the chamber 521 communicates with. port 5 3· Thus , the pressure PDF! acts upon piston face 511» The chamber 522 contains means for providing an adjustable opposing force consisting of a compression spring ^1 compressed between piston face 512 and a support 5^2, the position of the support ^ being adjustable by means of a screw 5*+3> rotatable by a handle S>M , . The opposing force is set at a value sufficient to counter* balance the action of the pressure PDFI when this pressure is at the critical level. A- art of the housing 0 forms the casing of a three-way two-position valve whose movable member is the piston 510 and pressure upon face 511 urges the piston 510 towards the open position of the valve Cshown in figure ) .

An Installation according to the present invention ca provide a variable flow of a driven luid to a delivery manifold under a nearly constant pressure, independently of fluctuations In the pressure at the driven fluid source of fluctuations in the pressure at the motive fluid source an of fluctuations in the back-pressure at the motive fluid outlet* Moreover , the consumption of motive power is restricted to the minimum necessary to reach the required level in the delivey manifold. Furthermore, said required level may easily be modified if needed. In addition, the installation prevents the drawbacks that could result from an interruption in the supply of driven fluid to the sy stem.-.

The invention Includes the case in which two or more pressure boosters , each provided with a regulator and a protective device, are connected in series and/or parallel and fed from a single motive fluid source.

It will be understood, that the invention Is not limited to the embodiments described and shown, and that it includes all variants falling within the scope of the claims that may be

Claims (1)

1. f A pressure boosting system for providing a variable flow ized motive flui ,, a u r ven pressure oos er o combine the pressure of the motive fluid and driven fluid received and deliver the driven fluid at the combined pressure, means for regulating the pressure of the motive fluid delivered to said pressure booster, and means for delivering motive fluid at said regulated pressure and driven fluid at said variable pressure to said pressure booster, wherein said regulating means comprise a control valve^^ having an inlet in communication with said motive fluid ft/ f ii~ source and an outletdror motive fluid at said regulated ■art-pressure, and means for actuating said control valve, including a pressure sensitive exposed to the pressure at the driven fluid outlet of said, pressure booster urging said valve to close and opposing means for urging said valve to open, A system as d fi ed in claim 1, wherein said opposing meanj · are adjustable to thereby allow modification of said required level of pressure. A system as defined in claim 1 or 2 wherein said opposing means comprise a compression spring compressed between a member movable with said valve and a support whose position is adjustable. A system as defined in any, one of claims 1 to 3» wherein said pressure sensitive element is a piston, movable within a housing and connected to or forming a part of said valve. . A system as defined in any preceding claim including valve means sensitive to the pressure at the driven fluid inlet of said pressure booster for interrupting the flow of motive fluid to said pressure booster when this last mentioned pressure is below a predetermined level · ·. Λ pressure boosting system, substantially as hereinbefore described and as shown in Figures 1 and 2 or Figures 3 and k of the accompan ing drawing. For the Applicants Dr. Yitzhak HESS