Abstract:
A valve housing ( 10 ) includes an inlet port ( 11 ) and two outlet ports ( 12, 13 ) for fluid passing through the housing. A valve element ( 15 ) accommodated in the valve housing is moveable freely between two end positions and has two surfaces ( 16 ) each adapted to close a respective outlet port in one and the other of the two end positions of the valve element. The valve element further includes members ( 20, 22: 21, 22: 21, 26, 47; 26, 48; 26, 50; 26, 51-54 ) for resetting between the positions. A double-action pump includes two spaces or rooms that have valve-controlled inlets and outlets ( 39, 40; 29, 30 ) for drive fluid and pump-transported working fluid respectively. The spaces are divided into an operating chamber ( 28 ) and a working chamber ( 27 ) by partition walls ( 26, 36, 37 ) which are pistons or diaphragms ( 26 ) and reciprocatingly move between end positions. The partition walls are interconnected by a movement transmission member ( 38 ) and working fluid is pressed out of one of the working chambers and drawn into the other. The operating chamber inlets ( 39 ) are each connected to a respective outlet port ( 12  or  13 ). The pump includes resetting member which at the end positions causes the valve element ( 15 ) to be moved over only a part of its movement path to its opposite end position.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related to REVERSING VALVE FOR A DIAPHRAGM PUMP to Svante Bahrton, Ser. No. 09/530,590 filed May 5, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a valve arrangement of the kind that includes a valve housing which has an inlet port and two outlet ports for fluid flowing through the housing. The valve housing accommodates a valve element that can move freely between two end positions and that has two surfaces which each co-act with a respective outlet port and which function to close an associated outlet port in respective first and second end positions of the valve elements. The valve arrangement further including means for switching the valve element between the positions. 
     2. Related Art 
     Valve arrangements of this kind are know, for instance, from U.S. Pat. No. 4,432,215. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a novel and advantageous method of integrating a valve arrangement of the aforesaid kind with a double-acting pump, wherewith there is obtained an arrangement that can be given only a few moveable parts, that will operate quickly and can be positively reset and that lacks any tendency of being set to a neutral position in which both of the outlet ports communicate simultaneously and permanently with the inlet port. 
     It is proposed to this end in accordance with the invention that the valve arrangement of the aforedescribed kind shall be coordinated with a double-acting pump of the kind that includes two spaces having valve-controlled inlets and outlets for a drive fluid and a pump-transported working fluid respectively, wherein each of said spaces is divided into an operating chamber and a working chamber by means of a respective partition wall in the form of a piston or diaphragm that can move reciprocatingly between end positions, and wherein the partition walls are mutually connected by movement transmission means and perform alternate working strokes under the influence of said drive fluid, during which working strokes working fluid is pressed out from one of said working chambers and drawn into the other of said working chambers, and vice versa, and wherein each of the operating chamber inlets is coupled to a respective outlet port of the valve arrangement and the pump includes resetting means which in the end positions of said partition walls causes the valve element located in one end position to move over only a part of its movement path to the is opposite position. 
     Further characteristic features of the invention will be apparent from the following objects wherein it is an object of the invention to provide the valve arrangement wherein a resetting means exerts temporarily on the valve element a mechanical or electromagnetic force that exceeds the force exerted by the fluid pressure on the valve element in the opposite direction. Each operating chamber is connected to an associated outlet port of the valve arrangement via a conduit which is adapted to be closed by the associated partition wall when the wall is located in one of its end positions, and in that a fluid bleed passageway extends between the outlet ports and the inlet port common to the outlet ports. 
     Another object of the invention is that each of the bleed passageways is comprised of a bore or channel that extends through the material of the valve housing or through associated valve element. 
     A still further object of the invention is that that partition walls include bellow-like structures which are open to the conduits and which function to generate an over pressure in an associated conduit when closing the conduit operating chambers are located close together on both sides of the valve arrangement, and in that the partition walls are provided with pins which each extend into a respective outlet port and, when the partition walls are in their inner end positions, act on an associated valve element surface to initiate resetting the valve element. 
     It is an object of the invention that the valve element is mounted on one end of a freely pivotal arm and has the form of a valve plate or disk which includes mutually opposite surfaces for alternate co-action with a respective outlet port. 
     A further object of the invention is that the valve element is connected mechanically to and adapted to drive a further valve element between two positions in which it connects either one or the other of two fluid inlet ports to a fluid outlet port which is common to the two inlet ports. 
     A still further object of the invention is that the pivotal arm carries on a second end a further valve plate or disc that has mutually opposite valve-element surfaces for co-action with a respective valve port in a further valve space. 
     Another object of the invention is that the operating chamber outlets are connected to the fluid inlets of the further valve element. 
     These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     From the following description of a number of chosen, exemplifying embodiments of the novel valve arrangement are illustrated in the accompanying drawings. 
     FIG. 1 is a highly schematic, sectional view of a first embodiment of an inventive valve arrangement. 
     FIG. 2 is a sectional view of a second embodiment of an inventive valve arrangement combined with a double-acting pump. 
     FIG. 3 is a sectional view similar to FIG. 2 but showing a modified resetting means. 
     FIG. 4 is a sectional view similar to FIG. 2 which shows a differently designed double-acting pump whose pump housing accommodates an inventive valve arrangement that includes a further modified resetting means. 
     FIG. 5 is a sectional view similar to FIG.  2  and shows yet another modified version of the resetting means. 
     FIG. 6 is a sectional view similar to FIG. 1 showing a modified resetting means. 
     FIG. 7 is a sectional view similar to FIG. 1, which show two bleed passageways. 
    
    
     DESCRIPTION OF THE INVENTION 
     Components that find correspondence or general correspondence in the different Figures of the drawings have been identified with the same reference signs. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     The valve arrangement illustrated in FIG. 1 comprises a valve housing  10  which includes an inlet port  11  and two outlet ports  12 ,  13  for fluid, either gaseous or liquid, flowing through the valve housing. The fluid is delivered at an overpressure from a source (not shown), as indicated by arrow  14 . The valve housing  10  accommodates a movable valve element  15  which has mutually opposite surfaces  16  for closing an associated outlet port  12  or  13  in a respective one or the other of two end positions of the valve element  15 . The orifices of respective outlet ports are surrounded by sealing rings  17 , to facilitate sealed closure of the valve. In the FIG. 1 embodiment the valve element  15  is comprised of a valve plate or valve disc, the mutually opposite sides of which form closing surfaces  16  and which is mounted on one end of a movable arm  18 . The arm  18  is mounted in the valve housing  10  at  19  for pivotal movement between said end positions, wherewith the surfaces  16  of said valve element close one or the other of said outlet ports  12 ,  13 . However, it lies within the scope of the invention to provide the valve-element surfaces on a valve element which has a different form than the illustrated valve element, for instance a substantially cylindrical or a substantially spherical form. In the illustrated case, the fluid entering through the inlet port  11  passes through the valve housing  10  and out through the open outlet port  13 . It is presupposed that the closed outlet port  12  is not placed under pressure and consequently the valve element  15  will be held pressed against the port  12  by the force exerted by the inflowing fluid. 
     FIGS. 1 and 7 illustrate the principle for resetting the valve arrangement, where the valve element  15  includes a through-penetrating bleed passage has or opening  20  of such small cross-sectional area that the flow through the bleed passageway or position in which it seals the outlet port  13 , so that fluid will now flow through the port  12  immediately the left closure means  22  has returned to the position in which the port  12  is open. bleed opining  20  will be essentially negligible in comparison with the total flow through the valve housing  10 . The bleed passageway or bleed opening  20  can be replaced with, e.g., two bleed passageways shown at  21  in FIG. 7 that extend between the inlet port  11  and a respective one of the outlet ports  12 ,  13 . As shown schematically at  22 , the valve arrangement also includes closure means for resetting the valve arrangement. The closure means are located downstream of the locations at which the bleed passageways  21  open into respective outlet ports  12 ,  13  and are intended to temporarily stop all flow of fluid through an associated outlet port. The closure means  22  and the bleed passageways  21  or bleed opening  20  thus form a valve arrangement resetting means. The valve is reset from the state or mode in which fluid passes in through the port  11  and out through the port  13  by movement of the closure means  22  shown on the left in FIGS. 1 and 7 to a state in which it closes the port  12 , in the arrow direction. As a result of the presence of the bleed opening or bleed passageways  20 ,  21 , there is built-up in the port  12  a static fluid pressure which generates on the surface of the valve element  15  lying proximal to the port  12  a force which exceeds the pressure exerted by the fluid flowing through the valve housing  10  on the,opposite surface of the valve element. As a result of the differential pressure caused by the fluid flow, the valve element  15  is swung rapidly away from its position in which it seals the port  12  and moves clockwise to its 
     FIG. 2 shows an inventive valve arrangement connected for controlling the operation of a double-acting diaphragm pump. The pump includes a generally cylindrical pump housing  23  which includes two spaces that are delimited by the end walls  24  of the housing and internal walls  25 . Each of these spaces is, in turn, divided into a working chamber  27  and an operating chamber  28  by means of a respective diaphragm unit  26 , said working chambers  27  being located close to one another and said operating chambers being located outwardly of their associated diaphragm unit  26 . Each of the working chambers  27  has valve-controlled inlets and outlets  29 ,  30  for working fluid transported by the pump, preferably a liquid working fluid. In the illustrated embodiment, the inlets and outlets  29 ,  30  have the form of openings in the inner chamber walls  25  and check valves  31  in the form of flap valves co-acting with said openings. The working fluid arrives in space  33  in the pump located between the walls  25 , in the direction indicated by arrow  32 , and leaves the pump through a diametrically opposite space  34  which is also located between the walls  25 , and exits said space  34  in the direction of arrow  35 . 
     The diaphragm units  26  include a round, relatively rigid central part  36 , and a peripheral part  37  which is comprised of a relatively pliable material and which is connected to the pump housing  23  at its radially outer edge. The diaphragm units  26  are g connected to one another by means of a rod  38  which transfers the movement of one diaphragm unit to the other, and vice versa. For instance, when the diaphragm unit  26  on the left in FIG. 1 moves to the right in response to pressurized operating fluid or drive fluid, e.g. compressed air, in the left operating chamber  28 , the rod  38  will press the right diaphragm unit  26  to the right as seen in the FIG.  1 . 
     The operating chambers  28  are provided at  39  and  40  with openings that serve as drive-fluid inlets and outlets respectively, wherewith the inlets  39  are connected via conduits  41  and a valve arrangement having the function described with reference to FIG. 1 to a pressurised fluid source, e.g. to a compressed air network. In addition to the valve element  15  mounted at  19  on the arm  18 , the valve arrangement includes a further valve element  42  in the form of a valve plate or valve disk mounted on the other end of the arm  18 , said arm  18  being pivotally mounted between its ends in the case of the illustrated embodiment. The valve element  42  is accommodated in the valve housing  10  in a space or valve room that is separated from the inlet and outlet ports  11 - 13  in a gas-tight and liquid-tight manner and the mutually opposite sides of which valve element close a respective one or the other of two inlet ports provided in the valve housing  10  for return fluid from the operating chambers  28 . The latter are connected to the ports  43  via the outlets  40  and conduits  44 . The area of the ports  43  is smaller than the area of the ports  12 ,  13  and said ports  43 , in turn, communicate with an outlet port  45  for return fluid that departs from the valve housing  10  in the manner indicated by the arrow  46 , depending on the position of the valve element  42 . The valve element  42  is reset by means of the valve element  15  and the arm  18  in a manner such as to establish communication between the operating chamber  28  and the outlet port  45  to the right in FIG. 2, provided that there is communication between the operating chamber  28  on the left of FIG.  1  and the operating-fluid inlet port  11  of the valve arrangement, whereas communication between the operating chamber  28  on the left in FIG.  2  and the outlet port  45  will be established provided that the operating chamber  28  on the right of FIG. 2 communicates with the inlet port  11  of the valve arrangement. 
     Disposed around the operating fluid inlets  40  are seals  47  with which the central parts  36  of the diaphragm units are brought into sealing contact when said diaphragm units  26  reach their outer positions, as illustrated on the right in FIG.  2 . 
     The valve arrangement illustrated in FIG. 2 operates in the following manner: The pressurised drive fluid or operating fluid passes to the left operating chamber  28 , through the inlet port  11 , the outlet port  12  and the conduit  41  connected thereto. The outlet port  43  on the left in FIG. 2 is held closed by means of the force exerted by the incoming drive fluid on the valve element  15 . The left diaphragm unit  26  is pressed to the right and therewith also presses the right diaphragm unit  26  to the right in FIG. 1, through the medium of the rod  38 . Working fluid is therewith pressed out from the left working chamber  27 , through the open outlet  30 , and is sucked into the right working chamber  27  through the open inlet  29 , while drive fluid departs through the outlet  40 , the conduit  44  and the port  45  of the right operating chamber  28 . When the central part  36  of the right diaphragm unit  26  has reached its end position and seals against the sealing ring  47  around the right inlet conduit  41 , there is built-up by the drive fluid entering the port  13  through its associated bleed passageway  21  a static overpressure which automatically resets the valve element  15  of the valve arrangement in the aforedescribed way. The flow through the pump and valve arrangement will therewith be reversed, i.e. drive fluid will be pressed through the port  13  and into the operating chamber  28  on the right of FIG.  2  and will leave through the left operating chamber, whereas working fluid will be pressed out from the right working chamber  27  and sucked into the left working chamber until the left diaphragm unit  26  reaches its outer end position and therewith automatically resets the valve element  15 . 
     The arrangement illustrated in FIG. 3 is similar to the arrangement illustrated in FIG.  2  and will be described solely with reference to those respects in which it differs from the FIG. 2 embodiment. The difference resides in the ability to avoid the use of bleed passageways, such as the passageways  20  or  21 , so that all drive fluid entering through the inlet port  11  can be used for useful work. In order to generate a force that will balance out the force exerted by the flowing working fluid on the valve element  15  and also the small force exerted by the flow of return fluid on the valve element  42 , the outer sides of the partition walls  26  are provided with bellows-like structures  48  that open towards a respective pump end-wall  24 . These bellows-like structures sealingly abut respective end-walls around the inlet  40  in the proximity of the end positions of the partition walls  26  and press used drive fluid through the conduit  41  connected to said inlet, so as to generate a valve-resetting pressure in that inlet port  12 ,  13  that is not at the moment in use, i.e. the port  13  in the state of the pump shown in FIG.  3 . 
     In the arrangement illustrated in FIG. 4, the double-acting pump is of the kind where the working chambers  27  are located proximal to the end-walls  24  of the pump housing and where the flow of medium through said chambers is controlled by ball valves  31 . The operating chambers  28  are thus located close to one another on opposite sides of a central pump-housing part  49  which includes a valve arrangement of the construction shown in FIG.  3 . Resetting of the valve element  15 , and therewith also of the valve element  42 , however, is initiated mechanically. The mutually facing sides of the central parts  36  of the partition walls  26  are provided to this end with pins  50  which extend axially into a respective outlet port  12 ,  13 . The length of the pins is adapted so that when the partition walls  26  occupy their inner positions, the pins  50  will press the valve element  15  slightly away from the position in which one of the mutually opposite surfaces  16  of said valve element closes an outlet port, either port  12  or port  13 , so as to thereafter reset the valve element is under the influence of the fluid flow through the valve arrangement, and therewith close the other outlet port. 
     The arrangement illustrated in FIG. 5 coincides with the arrangement illustrated in FIG. 2 except in the following respects: The bleed passageways  21  of the FIG. 2 arrangement have been replaced in the FIG. 5 arrangement with a balancing valve system that includes two valves  51 . The valves  51  are connected to a pressurised fluid network  52 , suitably the same network as that which delivers drive fluid to the inlet port  11 . Each of the valves can be connected to a respective drive-fluid conduit  41 , and therewith to a respective port  12 ,  13 , via conduits  53 . The valves  51  are two-position valves which are spring biased towards a normal mode or state in which the connection between the network  52  and the conduits  53  is broken, but which can be set against the action of said spring force to an active mode or state in which connection between network  52  and conduit  53  is established. To enable resetting or switching of the valves to be achieved, each of the valves includes a respective pin  54 . Each of the pins  54  projects into its respective chamber  28  and, as it engages a partition wall  26  approaching its outer end position, switches the valve concerned to its active state. In FIG. 5, the left valve  54  is in its normal state, or rest mode, in which connection between the network  52  and the conduit  53  is broken, whereas the right valve  51  has been switched to its active state or mode as a result of the partition wall  36  acting on the pin  54 , wherewith the outlet port  13  is connected to the compressed air network  52  via the right valve  51  and the conduits  53  and  41 . There is then generated briefly in port  13  an overpressure which causes resetting of the valve element  15 , therewith causing the partition walls  26  to move to the left in FIG.  5  and enabling the valve  51  to return to its rest mode. 
     FIG. 6 shows a further arrangement for initiating resetting of the valve. More specifically, the valve element  15  is comprised entirely or partially of magnetic material and, for instance, electromagnets  55  are mounted at or in the outlet ports  12 ,  13  so as to enable the valve element  15  to be moved electromagnetically a small distance from a position in which it closes one of the outlet ports  12 ,  13  and thereafter be swung to a position in which it closes the other outlet port in response to pressure differences occurring on opposite sides of said valve element. 
     It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof and that modifications can be made within the scope of the inventive concept as defined in the Claims. For instance the conduits  53  of the embodiment illustrated in FIG. 5 may open into associated operating chambers  28 . Similarly, the pins  54  may be attached to associated partition walls  26  and mounted for axial movement in the nearby pump end-wall, for resetting the valves  51  in the outer end positions of respective partition walls  26 . The movement transferring device  38  connected to the partition walls  26  may be sprung in the direction of its longitudinal axis, for instance in the manner shown in WO 96/34201, wherewith the operating chambers  28  may also be placed under pressure simultaneously for short periods of time, so as to avoid pulsations in the pumped working medium. The build-up of pressure in the port  12  or the port  13  may be controlled with the aid of throttle check valves in the conduits  41 . 
     It will be understood that for reasons of clarity, the valve arrangement illustrated in FIGS. 2-5 has been greatly enlarged in relation to the double-acting pump. However, the valve arrangement may be constructed for all manner of gas or liquid flows i.e. from very small to very large fluid flows, and the term liquid shall be understood to also include fluid/solids dispersions and slurries. 
     The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in theart, it is not desired to limit the invention to the exact construction and operation shown and described, and, accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.