WO1991013278A1

WO1991013278A1 - Selector valve

Info

Publication number: WO1991013278A1
Application number: PCT/SE1991/000139
Authority: WO
Inventors: Gunnar Fredberg
Original assignee: Miljöanalys G. Fredberg
Priority date: 1990-02-23
Filing date: 1991-02-22
Publication date: 1991-09-05
Also published as: AU7312591A; SE465635B; SE9000668D0; SE9000668L

Abstract

A selector valve for connecting at least one inlet or outlet line to any one of a number of fluid ports. The valve includes a plurality of closely adjacent valve elements (31-33) provided with through-passing openings which can be caused to communicate with one another in a predetermined fashion, by moving the valve elements relative to one another. The valve elements are arranged in a series from the one outer element (31) having a lowest order number to the other outer element having a highest order number. Each of the movable valve elements can be moved actively through a given distance, backwards and forwards in at least one given direction relative to the valve element having the next higher order number. Each valve element of a higher order number dogs passively each of the nearest adjacent, movable valve elements of lower order number. These valve elements therewith retain those relative positions taken in relation to one another and in relation to the valve element of higher order number.

Description

A Selector Valve

The present invention relates to a selector valve for coupling at least one inlet or outlet connection to a fluid port selected from a number of fluid-ports, said valve including to this end a plurality of closely adjacent valve elements provided with through-passing openings which can be caused to communicate with one another in a predetermined manner, by moving the valve elements relative to one another.

A selector valve of this kind finds use in many dif¬ ferent fields, such as when sampling and analyzing liquids or gases taken from one chamber or container of a plurality of chambers or containers, for instance when analyzing the environmental atmosphere in dif¬ ferent building locations. The valve, however, can also be used as a mixing valve for gases and liquids and as a programme mechanism in pneumatic and hydraulic sys- terns, etc.

Accordingly, one object of the invention is to provide a selector valve of this kind which has a simple and reliable function, which can be manufactured rational- ly, and which has a modular construction such as to enable a large number of fluid ports to be connected to the valve.

Another object of the invention is to provide a selec- tor valve which will enable the valve to be switched from any setting to any other desired valve setting without passing through intermediate valve positions.

A further object of the invention is to provide a selector valve which can be given a logic construction such as to obtain a function which corresponds to the function of electronic logic circuits, so as to enable the valve to be adapted to and used in computer con¬ trolled systems or computer monitored systems.

Still another object of the invention is to provide a selector valve which includes only a small internal dead volume.

These objects are achieved by means of a selector valve of the kind described in the first paragraph of this specification which is characterized in that the valve elements form a series from the one outer element having a lowest order number to the other outer element of the highest order number; in that each of the mov¬ able valve elements can be moved actively backwards and forwards through a given step in at least one given direction in relation to the valve element having the nearest higher order number; and in that when moved actively each valve element having a higher order number passively entrains or dogs each of the nearest adjacent movable valve elements having a lower order number in those relative positions which said elements adopt in relation to each other and in relation to said valve elements of said higher order numbers.

In the case of one embodiment which utilizes linear movements in one and the same direction, the valve elements have the form of slides which are superimposed one on the other to form a stack, these slides being displaceable relative to one another in mutually the same direction, and each slide being configured with a row of openings which extend in said displacement direction. According to another embodiment, the valve elements have the form of concentrical tubes which can be dis¬ placed axially relative to one another and each of which is configured with a row of openings which extend in said axial direction. By arranging the concentrical tubes in the form of telescopically movable piston/ cylinder assemblies, the desired axial movements of the tubes can be achieved in a highly beneficial manner.

According to another embodiment of the invention, the valve elements have the form of discs which can be rotated relative to one another about a common axle and each of which is provided with a series of openings which extend around the periphery of a circle concen- trical with said axle. The axle may be a hollow axle and used as an additional passageway which extends through the valve elements, such as to enable all con¬ nections to the valve to be effected with one and the same valve element.

In accordance with another embodiment, the valve ele¬ ments comprise slides which are superimposed to form a stack and which can be displaced relative to one an¬ other in two mutually perpendicular directions. In this case, each displaceable slide is displaceable actively in only one of these directions relative to the slide having the nearest higher order number. The slides are configured with openings disposed in rows which extend parallel with said directions. This construction ac- hieves a large number of valve setting positions while retaining relatively small valve dimensions and enables

the valve elements to be controlled with computer- adapted logic. A simplified version of the inventive selector valve, in which at least one of the valve elements is movable in two mutually perpendicular directions, is charac¬ terized in that the valve elements comprise a number of circular-cylindrical bodies disposed concentrically with one another; in that said bodies fit into one another and are rotatable relative to each other; and in that at least one of said bodies is also displace¬ able axially in relation to an adjacent body. This embodiment minimizes the number of valve sealing points and further reduces the dead volume of the valve as¬ sembly. In this case, the fluid ports are preferably arranged in the radially outermost of said bodies, in the form of two mutually parallel rows of openings extending in .the circumferential direction of said body.

In the case of the aforedescribed embodiments, it is preferred that the means used to drive the valve ele- ents is constructed and arranged so that all valve elements can be re-adjusted positionally between their respective terminal positions at one and the same time.

Other characteristic features of the invention are evident from the following Claims.

The invention will now be described in more detail with reference to the accompanying drawings, in which

Figure 1 is a schematic illustration of one application of the inventive selector valve;

Figure 2 is a perspective view of one embodiment of an inventive selector valve; Figure 3 illustrates schematically the hole patterns and the function of the valve shown in Figure 2;

Figure 4 is a cross-sectional view of a second embodi¬ ment of the inventive valve;

Figure 5 is a perspective view of a third embodiment of the inventive valve, comprising rotatable valve ele¬ ments;

Figure 6 illustrates a fourth embodiment of the inven¬ tion in which the valve elements can be displaced in two directions;

Figure 7 illustrates a further development of the selector valve shown in Figure 6;

Figure 8 is a perspective, exploded view of a further development of the inventive selector valve;

Figure 9 illustrates different relative positions between the valve elements of the valve shown in Figure 8; and

Figure 10 is a side view of the valve element illustra¬ ted in Figure 9.

Figure 1 illustrates an application field in which an inventive selector valve is connected between analysis equipment 2 and four different chambers 3 whose at¬ mospheres are to be analyzed. Respective chambers 3 can be connected to the analyzing equipment 2 either manually or in accordance with a predetermined pro¬ gramme, in a selected order and during selected periods of time, by means of the inventive selector valve. Alternatively, Figure 1 can be said to illustrate a system for mixing liquids stored in respective chambers

3 in desired proportions in a mixture container 2. The valve may also have an opposite function, namely one of dispensing, e.g., liquid from a container 2 to a con¬ tainer 3 selected from a number of containers 3.

The aforesaid applications are solely examples of the different contexts in which the inventive selector valve can be used.

The selector valve according to the Figure 2 embodiment comprises three slides 4, 5, 6 arranged closely on top of one another, and a stationary bottom valve element 7.

The Figure shows the slides in their right-hand ter¬ minal positions, from which each of the slides is intended to be moved through one step of given length to the left in the Figure in relation to the nearest underlying slide. Displacement or axial movement of an underlying slide is accompanied by the slide or slides located above said underlying slide.

In the case of the illustrated embodiment, an overlying slide is displaced axially in relation to the nearest underlying slide by means of an electric motor 8 provi¬ ded with an excentric pin which is movable freely in a slot 9 provided in said underlying slide.

In the case of the Figure 2 embodiment, the upper slide

4 includes three through-passing openings 10 intended for common connection to an outlet or an inlet line. By means of an appropriate arrangement of corresponding openings in the underlying slides 5 and 6, the line can be connected to any one of eight fluid ports 11 con¬ nected to the bottom, stationary valve element 7 in correspondence with the mutual relative positions of the movable slides, as described in more detail below with reference to Figure 3.

Each opening is suitably encircled by an O-ring (not shown) , in order to provide a requisite seal between the mutually opposite openings of two adjacent slides. In order to reduce the friction which acts between the slides as they are displaced axially with relation to one another, adjacent slides are preferably coupled together by means of guide arms 12 which enable the slides to move separately to some extent during the actual movement of the slides and to again be urged together in the other terminal position by a force acting axially on the slides.

The part illustrations a-h of Figure 3 illustrate the operating principle of the selector valve shown in

Figure 2. The same principle is applied in the embodi¬ ments illustrated in Figures 4 and 5, even though the hole patterns are changed.

Figure 3a illustrates the movable slides 4, 5 and 6 and the stationary bottom valve element 7 , the openings of which correspond to the aforesaid eight fluid ports. As shown in the Figure, the three openings of the slide 4 are commonly connected to an input line 13. Both of the slides 5 and 6 of this embodiment are configured with four openings. The values of these movable slides 4, 5, 6 in a binary system have been noted in parenthesis to the left of said slides, these values thus being 1, 2 and 4 respectively. The fluid ports in the stationary or fixed valve element 7 have been given bracketed numerals corresponding to the binary values of the slides.

In the Figure 3a illustration, all of the slides are shown schematically in a non-activated position, with

•the input line 13 connected to the fluid port 0 via the mutually communicating openings in the movable slides located above this port. All other fluid ports are disconnected from the input line.

In the Figure 3b illustration, the slide 4 having the binary value 1 is shown to be activated and displaced axially to its other terminal position, in which the input line 13 is connected to output port number 1, while breaking the connection to the output port 0, as illustrated.

In the Figure 3c illustration, solely the slide 5 having the binary value 2 has been activated. As before mentioned, however, activation of this slide will result in passive dogging or entrain ent of the overly¬ ing slide 4, resulting in^' connection of the input line 13 with output port number _.2.

In the Figure 3d illustration, both the slide 4 having the binary value 1 and the slide 5 having the binary value 2 have been activated, wherewith each of these slides has been moved one step in relation to the nearest underlying slide. The slide 4 thus is dogged by the slide 5. The values 1 and 2 of the slides are summated, causing the input line 13 to be connected to output port number 3.

Analogously herewith, in Figure illustrations 3e, f and g the input line is connected with the fluid ports 4, 5 and 6 respectively and in Figure 3h the input line is connected with fluid port number 7, since in this Figure illustration all slides having the values l, 2 and 4 are activated and summated to 7. It should be observed that only the values of those slides which are activated are summated in each individual case.

It will be understood that because of its binary func¬ tion, the aforedescribed valve is highly useful in a computer-adapted environment. The illustrated hole patterns of the slides also enables each slide to be displaced axially through the same distance when ac¬ tivated, which is very advantageous in many contexts. Furthermore, the openings extend straight through respective slides, which simplifies manufacture. The hole patterns can be varied, however, in several res¬ pects. This is particularly the case when the various slides can be stepped through mutually different dis¬ tances and/or when the openings extending therethrough are inclined. Neither is the valve limited to only eight fluid ports, since it is possible to extend the number of fluid ports by adding more slides to the valve assembly and by varying the hole patterns in said slides. In this case, such additional slides will be given the values 8, 16, 32 ... so as to enable 16, 32, 64 ... fluid ports to be used, and therewith retain the advantages afforded by a binary system. For the sake of simplicity, the bottom valve element of the illustrated embodiment is considered to be stationary. The afore- described function can be achieved, however, irrespec¬ tive of which of the valve elements is stationary. Although the use of a stationary valve element is not absolutely necessary, the use of a stationary element simplifies the practical use of the inventive valve. One very important advantage obtained with a valve having the function illustrated in Figure 3 is that the valve can be switched selectively from one setting to another at any moment in time without the valve needing to pass through intermediate valve settings. This is achieved by simultaneous activation of all of the slides which need to be activated for adjustment of the valve to the new setting. Thus, the valve setting or valve access time is constant and independent of the prevailing position or number of the fluid port. This is achieved because no slide need be moved, or can be moved, nore than one step in relation to the nearest underlying slide.

Figure 4 illustrates another embodiment of the inven¬ tive selector valve, in which the principle illustrated in Figure 3 is applied. In the Figure 4 embodiment, the valve elements have the form of mutually concentric tubes 14, 15, 16 and 17 which correspond to the valve elements 4, 5, 6 and 7 of the Figure 3 embodiment.

The tubes are mutually telescopic and are shown in their left-hand terminal positions. The tubes are fitted at respective ends thereof with end walls 18, 19, 20, 21, wherein they can also function as piston/ cylinder units for achieving axial, relative movement of the tubes by delivering pressure fluid to the spaces between said end walls. An input opening 22 is in constant communication with a central cavity 50 in the inner tube 14, through communicating openings 51 in the tube walls. Similar to the Figure 3 illustration, the cavity 50 connected to the input opening 22 can be connected, via three openings 52 in the wall of the tube 14 to any desired one of the eight output openings in the tube 17, through four mutually coacting openings in each of the intermediate tubes 15 and 16. Similar to the Figure 3 embodiment, the eight output openings have been provided with order numbers noted in parenthesis.

The three openings in the tube wall located adjacent the left end and the right end respectively of the tube 17 are intended to receive control pressure which is operative in displacing the tubes axially within one another, these tubes functioning as pistons. The open- ings have been given signs or notations conventional in the binary system. Thus, when the tubes are located in their illustrated positions, a control pressure is applied at the inputs H, ^"2 and ^"4 , which causes all tubes to move to their left-hand terminal positions, with the input connection 22 connected to output number 0. Remaining outputs can be connected, by applying pressure to the control inputs in accordance with the following truth table.

Truth Tabl e

Output Number Inputs

1 2 4 1 2 4

0 X X X 1 X X X 2 X X X 3 X X X 4 X X X 5 X X X 6 X X X 7 X X X

The embodiment illustrated in Figure 4 is very compact and provides a fully encapsulated selector valve, which will also function well in a computerized environment. Figure 5 illustrates an inventive selector valve com¬ prising valve elements in the form of round discs 23, 24, 25, 26 which can be rotated backwards and forwards on an axle 27. Each disc is provided with a series of through-passing openings which are disposed around the circumference of a circle having the same radius in the various discs. The hole patterns in the discs can therewith coincide with the hole patterns in the slides of the Figure 3 embodiment, although other hole pat¬ terns can be used, depending on stroke lengths and the number of discs^"used.

As will be seen from the Figure, each disc can be rotated through a given angle, backwards and forwards in relation to the nearest adjacent disc, by means of an electric motor 28 which drives a pinion wheel 29 and a toothed wheel 30. The axle 27 on which the discs are mounted may be a hollow axle and therewith also func- tion as an inlet or outlet passage, which in the il¬ lustrated embodiment is connected with the three open¬ ings in the outermost disc 23. In this way, all exter¬ nal connections to the valve may be made on the front surface of the disc 26.

Cupped discs may be used as an alternative to flat discs, wherewith a larger space for :he openings is obtained when these openings are disposed on the flank surfaces of respective cupped discs.

Figure 6 illustrates the principle construction of an inventive selector valve which comprises two slides capable of being displaced perpendicularly to one another. For the sake of simplicity, only two movable slides 31, 32 are shown in Figure 6, together with a bottom, stationary valve element 33 configured with four fluid ports.

The upper disc 31 contains one opening and is displaced horizontally in one direction by means, for instance, of a pneumatic piston-cylinder device 34, whereas the intermediate disc 32 has two openings and is displaced horizontally in the other direction by means of another pneumatic piston-cylinder device 35. It will be seen that by displacing one and/or the other of said slides 31 and 32 through one step with the aid of respective piston-cylinder devices, it is possible to connect the single opening in the slide 31 with any one of the four openings of the valve element 33. In principle, this action is similar to the action of the earlier des¬ cribed embodiments, namely that an overlying slide is displaced actively through only one step in one direc¬ tion in relation to an underlying slide, but that said overlying slide will also be dogged passively by the underlying slide as said slide moves.

Instead of the bottom valve element being stationary, the intermediary slide 32 may be fixed, in which case it must be possible to move the bottom element recipro- catingly through one step.

As will be understood, although Figure 6 shows only three valve elements, the number of elements may be increased as required. In the case of a large number of output ports, however, problems are encountered in practice when it is desired to maintain the same, reasonable length of slide stroke with an upper slide which is configured with one single hole while avoiding oblique openings through the slides. These problems can be alleviated, however, with a modified hole pattern, in which, for instance, there is used an upper slide provided with several openings which are connected commonly to an inlet or outlet line.

Figure 7 illustrates a further embodiment of the valve according to Figure 6, comprising three movable slides 36, 37 and 38 which can be displaced one step in one of two perpendicular directions relative to an underlying slide or a bottom, stationary valve element 39 which is provided with eight openings for connection to fluid lines. Those openings in the valve element 39 and the slide 36, 37, 38 which are ringed with a broken-line rectangle are intended to form, in all positions of the slides, an open return passageway which extends down from the upper surface of the top slide 36 to the valve element 39.

As will be seen from the Figure, each of the movable slides contains four valve openings in addition to these openings which form the return passageway, which enables a closed space beneath a cover member 40 and located above the upper slide 36 to be connected with any selected one of the eight openings in the bottom valve element 39, by appropriate relative displacements of the movable valve elements in the arrowed direc¬ tions.

The movable slides are displaced with the aid of ex- centric mechanisms driven by electric motors 41, 42 and 43. Thus, the slide 36 is displaced by the motor 41 mounted thereon, the excentric mechanism of said motor extending down through the opening 44 into coaction with the slot 45 in the nearest underlying slide 37. Thus, when the motor 41 rotates, the slide 36 will be displaced backwards and forwards relative to the slide 37 in the arrowed direction, through a distance deter¬ mined by the excentric.

Similarly, the slide 37 is displaced relative to the slide 38 by means of the motor 42, the excentric mechanism of which passes down through the opening 46 in the slide 37 and into coaction with the slot 47 in the nearest underlying slide 38. The slide 38, in turn, is displaced relative to the slide 39 by means of the motor 43, the excentric mechanism of which passes down through the opening 48 in the slide 38 and into coac¬ tion with the slot 49 in the stationary valve element 39.

When more output ports are required, the valve can be extended with more slides.

From a connection aspect, it is suitable for the bottom valve element to be stationary. If desired, however, any of the other slides may be stationary and, similar to other embodiments, none of the slides need be sta¬ tionary when the valve arrangement, for instance, can be suspended from the drive means. In the case of the aforedescribed embodiment, adjacent slides are actively displaceable in mutually different directions. Depend¬ ing on the hole patterns used, mutually adjacent slides may be actively displaceable in one and the same direc¬ tion.

Figure 8 illustrates a further development of the inventive selector valve, which in this case comprises three circular-cylindrical valve elements 50, 51 and 52. This embodiment differs from the aforedescribed embodiments in that at least one of the valve elements can be moved in two mutually perpendicular directions. Thus, in the illustrated embodiment, the valve element 50 has the form of a circular-cylindrical plug with a through-passing passageway 53 which has two inlet openings and one outiet opening, and the valve element can be rotated and displaced axially in relation to the surrounding, cylindrical valve element 51.

The valve element 50 can be rotated relative to the valve element 51 between two terminal positions, which in the illustrated embodiment are determined through the coaction of arms 54 with a stop element 55 mounted on a tongue 56 which projects out from the valve ele¬ ment 51. The valve element 50 can be adjusted axially between two positions with the aid of an arm 57 mounted on the tongue 56 and coacting with a top flange on the valve element 50.

The valve element 51 includes two plates 58, 59, each provided with four holes and let-into the cylindrical wall of said element. The plates are suitably made of rubber or some like material in order to provide fluid- tight connections between the holes in the plates and holes in the nearest, inwardly lying and outwardly lying valve element 50 and 52 respectively.

In the illustrated embodiment, each of the rubber plates 58 and 59 include two mutually horizontal and mutually parallel rows of holes, with two holes in each row. As will be seen from the sectional view presented in Figure 8b, the upper holes in the plate 58 are referenced 60 and 61 and in the plate 59 with reference numeral 62 and 63. That imperforate part of the rubber plate 58 and 59 which surrounds each of the holes functions as an inner and an outer sealing 0-ring around respective holes. The valve element 51 is, in turn, rotable in relation to the outer valve element 52 between two terminal . positions, which are defined by coaction of the tongue 56 with two stop shoulders 66 on the valve element 52. When the valve element 51 rotates in relation to the valve element 52, the element 50 is also dogged in the adopted position relative to the valve element 51.

The valve element 52 includes two horizontal rows of openings with two inlet openings 64 and 65 in each row, said openings being connected to a common chamber having a common inlet line. The valve element 52 also includes eight outlet openings arranged in two horizon- tal rows, with four openings in each row, as will be seen from Figure 10. These openings are referenced with bracketed numerals corresponding to the binary values of the valve elements, as will be described in more detail with reference to Figure 9. The valve element 52, which forms a surrounding casing, is divided into two parts to permit adjustments to be made to the abutment pressure and therewith the seal against the inwardly lying valve element 51.

Similar to the embodiments earlier described, the common input line connected to the input openings 64 and 65 can be connected to any one of the eight out¬ puts, depending on the relative positions of the valve elements. Any appropriate means (not shown) may be used to rotate and axially move the valve elements. The manner in which the valve operates is described in more detail herebelow with reference to Figures 9 and 10, wherein, by way of example, rotation of the inner element relative to the nearest outwardly lying element represents the binary value 1 and corresponding rota- tion of the last mentioned element relative to the outermost element represents the binary value 2.

In the Figure 9a illustration, all valve elements are non-activated, wherein the inlet communicates with the fluid port (0) through the communicating openings in respective valve elements.

In the Figure 9b illustration, the inner valve element 50 has been rotated to its other terminal position, which represents the binary value 1, wherein the inlet is connected with the fluid port (1).

Figure 9c illustrates the situation in which only the intermediate valve element 51 has been activated and rotated to its other terminal position, which repre¬ sents the binary value 2, while dogging the inner valve element 50. The inlet, in this case, is connected with the fluid port ( 2 ) .

In the Figure 9d illustration, both the valve element 50 and the valve element 51 have been activated, which means that the inner valve element 50 has been rotated relative to the valve element 51 and the valve element 51 rotated relative to the valve element 52. Thus, the valve elements having the binary values 1 and 2 have been activated and the inlet is thus connected to the fluid port (3) = (1 + 2).

The aforedescribed rotational movements are assumed to have been effected with the valve element 50 in a raised position, to which it is moved by the lever arm 57. When the valve element 50 is pressed down, so that the passageway 53 will coact with the bottom rows of openings in the rubber plates 58 and 59, these openings in turn coacting with the bottom rows of openings in the valve element 52, the binary value 4 is represen¬ ted, wherewith the inlet will be connected with the fluid port (4) in the starting position shown in Figure 9a. The ports (5), (6) and (7) can also be connected by adding 1, 2 and 3 respectively to the binary value 4, by corresponding rotation of the valve elements as described above with reference to Figure illustrations 9b-c.

As will be understood, a relative displacement axially between the valve elements 51 and 52 may be used in¬ stead of an axial displacement between the valve ele¬ ments 50 and 51, in which case the element 50 will accompany the axial movement of the valve element 51. In this case, the rubber plates 58 and 59 need only be provided with a respective single row of two openings for the purpose of achieving connection with one of the eight output ports. If a larger number of output ports is required, however, additional valve elements must be included. Alternatively, the two inner valve elements 50 and 51 may be both rotatable and axially displace¬ able in relation to one another and in relation to the outer valve element 52.

The invention has been described in the aforegoing with reference to a number of selected exemplifying embodi¬ ments. It will be understood, however, that these embodiments may be modified in several respects within the scope of the following Claims, particularly with respect to the slide hole patterns and the slide con¬ figurations. The invention has also been described with reference to its particular suitability in the context of binary environments. The invention can be adapted, however, to any system and the number of fluid ports that can be connected may be chosen independently of the numerical system which is used. When a larger number of connection possibilities are required, the valve may be divided suitably into modules. For in- stance, if it is desired to connect 64 fluid ports, the ports can be divided into four groups of 16 ports which can be served by means of valve arrangements working in parallel. Such an arrangement will thus retain the facility of enabling direct access to a desired fluid port. Respective slides may be stepped with the aid of any appropriate means, and drive means alternative to the aforedescribed excentric mechanisms and piston/ cylinder units include electromagnetic drive means or the like. The valve elements may also be moved manually.

Claims

1. A selector valve for connection of at least one inlet or outlet connection (13; 22; 27) to a fluid port selected from a number of fluid ports (0-7), said valve comprising a plurality of closely adjacent valve ele¬ ments (4-7; 14-17; 23-26; 31-33; 36-39), each of which is provided with through-passing openings which can be caused to communicate with one another in a predeter- mined fashion by moving the valve elements relative to one another, c h a r a c t e r i z e d in that the valve elements form a series extending from the one outer element having a lowest order number to the other outer element having a highest order number; in that each of the movable valve elements (4-7; 14-16; 23-25; 31-32; 36-38) is actively movable backwards and for¬ wards through a given distance in at least one given direction relative to the valve element of the nearest higher order number; and in that when moved actively each said valve element of a higher order number pas¬ sively dogs each of the nearest adjacent, movable valve elements having a lower order number in those relative positions adopted by said valve elements in relation to one another and in relation to said valve element of higher order number.

2. A valve according to Claim l, c h a r a c ¬ t e r i z e d in that said valve elements have the form of slides (4-7) which are superimposed to form a stack; in that said slides are axially displaceable relative to one another in one and the same direction; and in that each slide is configured with a row of openings, said rows extending in said one direction.

3. A valve according to Claim 1, c h a r a c ¬ t e r i z e d in that said valve elements have the form of tubes (14, 17) which are concentrical with one another; in that said tubes can be displaced axially in relation to one another; and in that each tube is provided with a row of openings, said rows extending in said direction.

4. A valve according to Claim 1, c h a r a c - t e r i z e d in that said valve elements have the form of discs (23-26) which are rotatable relative to one another on a common axle; and in that each disc is configured with a series of openings disposed on the circumference of a circle concentrical with said axle.

5. A valve according to any one of Claims 2-4 for connection of an inlet or outlet connection to any selected one of eight fluid ports, c h a r a c ¬ t e r i z e d in that the valve includes three movable valve elements (4-6), of which the valve element having the lowest order number (4) is provided with three openings (10) which are connected commonly to said inlet or outlet connection; in that the valve element having the nearest higher order number (5) is provided with four openings; in that the valve element having the next following order.number (6) is provided with four openings; and in that the last mentioned valve element (6) is movable in relation to a following valve element (7) provided with eight openings which form said fluid ports (0-7).

6. A valve according to Claim 1, c h a r a c ¬ t e r i z e d in that said valve elements have the form of slides (31-33; 36-39) superimposed to form a stack; in that said slides are displaceable relative to one another in two mutually perpendicular directions in a manner such that each displaceable slide can be displaced actively in solely one of said directions relative to the slide having the next higher order number; and in that the slides are provided with open¬ ings arranged in rows parallel with said directions.

.

7. A valve according to Claim 1, c h a r a c ¬ t e r i z e d in that said valve elements have the form of circular-cylindrical bodies (50, 51, 52) which are concentrical with one another; in that said bodies fit into one another and are rotatable relative to each other; and in that at least one (50) of said bodies is also capable of being displaced axially in relation to an adjacent valve body (51).

8. A valve according to Claim 7, c h a r a c ¬ t e r i z e d in that said fluid ports are disposed in the radially outermost (52) of said valve bodies and have the form of two, mutually parallel rows of open¬ ings which extend circumferentially around said body.

9. A valve according to any one of Claims 1-8, c h a r a c t e r i z e d in that all of the movable valve elements can be re-positioned simultaneously between their terminal positions.

10. A valve according to any one of Claims 1-9, c h a r a c t e r i z e d in that the movable valve elements are re-positioned with the aid of drive means (8; 28; 34-35; 41-43) which work between respective movable valve elements and the element having the next higher order number.