Diaphragm valve

A diaphragm valve including a valve housing having at least three ports and at least two valve chambers provided in the valve housing. Each valve chamber has at least one first space communicating with a respective one of the ports and a second space separated from the first space by a threshold. The second space of each valve chamber communicates only with the second space of others of the at least two valve chambers, such that communication between any two of the at least two ports can take place only by passing across two thresholds.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention concerns a diaphragm valve for controlling a flow of
 gaseous or liquid fluid and, particularly, to direct such flow from at
 least one port of the valve to at least one other port of the valve.
 2. Related Art
 WO 95/00782, by the present inventor, describes such a diaphragm valve
 including a valve housing having a substantially circular valve chamber,
 into which opens a central channel and on each side thereof a first side
 channel and a second side channel. Each side channel has an external
 connection for fluid and is separated from the central channel by means of
 a respective one of two substantially parallel valve seat means extending
 like chords across the valve chamber. Each valve seat means provides a
 substantially linear valve seat for an elastic diaphragm. The diaphragm is
 adapted to be brought into and away from sealing contact with at least one
 of the valve seat means. Two individually operable control means are
 adapted both to press a respective linear portion of the diapghragm
 against a respective valve seat, thereby to shut passage of fluid between
 the central channel and a respective side channel, and to positively raise
 a respective portion of the diaphragm off a respective one of the valve
 seat, thereby to open a flow passage between the central channel and the
 respective side channel.
 This prior art three-way/three-port diaphragm valve proved to operate
 extremely well. There was, however, a desire to convert it to a
 4-way/4-port valve, i.e., a valve for mixing three flows, or, to direct
 flow from one external connection (inlet port) to one or more of three
 other external connections (outlet ports).
 That was accomplished by a first development of the valve as initially
 stated. This first development is described in WO 97/17558 by the same
 inventor. In the diaphragm valve according to the first development, the
 valve housing is provided with a second substantially circular valve
 chamber, into which opens a fourth channel having an external connection
 for fluid and which communicates with the central channel through an
 opening in the valve housing. A second elastic diaphragm is provided and
 is adapted to be brought into and away from sealing engagement with a
 third valve seat means provided in the second valve chamber. A third
 control means is arranged both to press the second diaphragm against the
 third valve seat means, thereby to shut passage of fluid between the
 fourth channel and the central channel, and to release the diaphragm from
 its engagement with the third valve seat means, thereby to open passage of
 fluid between the fourth channel and the central channel.
 Also this valve has proven to satisfactory fulfil its objects.
 Common to the two prior art valves mentioned is a central channel having
 direct communication with an associated port. Consequently, this port
 becomes involved also in fluid transfer between the remaining two ports in
 the valve according to WO 95/00782 and between any combination of two of
 the remaining three ports in the valve according to WO 97/17558.
 SUMMARY OF THE INVENTION
 It is an object of the present invention to provide a diaphragm valve
 allowing transfer of fluid between any combination of at least two of its
 ports without any other port being involved. In achieving this, the new
 diaphragm valve shall comply with the same extensive sanitary requirements
 as the prior one, it shall be simply and reliably operable and have
 relatively few movable parts.
 In a diaphragm valve of the kinds described above, the valve seats can be
 characterized as thresholds or weirs between adjacent channels and
 associated ports. Communication between two ports is established by fluid
 passage across but one threshold.
 To achieve the object of the present invention, it is proposed that the
 central channel be replaced by a central space having no direct
 communication with any port. Fluid passage from a port to the central
 space must take place across a threshold, and passage from the central
 space to any other port must take place across a further threshold. Thus,
 all flow across the valve has to pass the central space.

Like the membrane valve described in WO 97/17558, the valves according to
 the first and second embodiments of the present invention described with
 reference to FIGS. 1-4 and FIGS. 5-9, respectively, include a valve
 housing having an upper and a lower valve chamber, each having valve seat
 means and an elastic diaphragm as well as an operating unit capable of
 controlling movements of the associated diaphragm so as to bring it into
 and away from sealing contact with the respective valve seat means.
 Since is is preferred to utilize operating units as described in WO
 97/17558 with the embodiments of the present invention, they will not be
 described herein in detail.
 The first embodiment of the present invention described in FIGS. 1-5
 includes a four port valve housing 10 having an upper valve chamber 11 and
 a lower valve chamber 12 provided in opposite parallel flat surfaces 10a,
 10b of the valve housing 10. It appears from FIGS. 1 and 2 that the valve
 chambers are substantially circular in plan view, and from FIGS. 3 and 4
 that they are substantially bowl or plate shaped in side view.
 Extending like parallel chords across the upper valve chamber 11 are two
 valve seat means in the shape of weirs or thresholds 13 and 14 (FIG. 1).
 Interiorly provided in the valve housing 10 are well-like channels 15, 16
 (see FIG. 4) that open in the valve chamber 11 radially outside the
 thresholds 13, 14, respectively, and communicate with respective ports A
 and C.
 Similarly, the lower valve chamber 12 has two parallel valve seat means in
 the shape of weirs or thresholds 17, 18 extending like parallel chords
 over the valve chamber (FIG. 2). Interiorly provided in the valve housing
 10 are likewise well-like channels 19, 20 that open in the valve chamber
 12 radially outside the thresholds 17, 18, respectively, and communicate
 with respective opposite ports B and D.
 As appears from FIGS. 1 and 2, the ports A and C are mutually aligned and
 diametrically opposed to each other as are the ports B and D. It also
 appears that the common axis of the channels 15 and 16 and their
 associated ports A and C and the common axis of the channels 19 and 20 and
 their associated ports B and D are perpendicular to each other, and,
 further, that the mutually parallel thresholds 13, 14 associated to the
 channels 15, 16 are perpendicular to the mutually parallel thresholds 17,
 18 associated to the channels 19, 20.
 Between the thresholds 13, 14 of the upper valve chamber 11 is provided a
 substantially V- or funnel-shaped recess or cavity 21 (FIG. 3) tapering
 from substantially the diameter length of the valve chamber 11 towards the
 lower valve seat 12 where it opens between the thresholds 17 and 18. The
 width of the cavity equals the distance between the thresholds 13 and 14.
 Correspondingly, between the thresholds 17, 18 of the lower valve chamber
 12 is provided a likewise substantially V- or funnel-shaped recess or
 cavity 22 (shown inverted in FIG. 4) tapering from substantially the full
 diameter length of the valve chamber 12 towards the upper valve seat 11
 here it opens between the thresholds 13 and 14. The width of the cavity 22
 equals the distance between the thresholds 17 and 18.
 Together, the cavities 21 and 22 form a central space 23 extending through
 the valve housing 10 between the valve chambers 11 and 12 and having no
 communication with any of the ports A, B, C and D except across a
 corresponding threshold 13, 14, 17 and 18, respectively.
 Shown in FIGS. 3 and 4 are an upper diaphragm 24 and a lower diaphragm 25
 adapted for cooperation with the thresholds 13, 14 of the upper valve
 chamber 11 and with the thresholds 17, 18 of the lower valve chamber 12,
 respectively. In order not to interfere with details of the valve housing,
 the diaphragms are shown spaced from the upper surface 10a and the lower
 surface 10b, respectively, of the valve housing 10. In operation, the
 diaphragms are clamped between respective upper and lower operating units
 26, 27 and the upper valve housing surface 10a and the lower valve housing
 surface 10b, respectively. Both operating units schematically shown in
 FIGS. 3 and 4 are suitably of the first kind described in WO 97/17558
 having two control means selectively movable in the directions indicated
 by arrows F.sub.1, F.sub.2, F.sub.3 and F.sub.4 to press one portion each
 of a diaphragm 24, 25 against a respective threshold 13, 14 and 17, 18,
 and to raise corresponding portions off the thresholds.
 Now, by choosing different combinations of pressing and raising diaphragm
 portions, flow between the different ports may be established at least as
 appears from the following table:

Two-way communication between ports
 A .rarw..fwdarw. B C .rarw..fwdarw. B A + C .rarw..fwdarw. B A
 .rarw..fwdarw. C D .rarw..fwdarw. B
 F.sub.1 + F.sub.1 - F.sub.1 + F.sub.1 + F.sub.1 -
 F.sub.2 - F.sub.2 + F.sub.2 + F.sub.2 + F.sub.2 -
 F.sub.3 + F.sub.3 + F.sub.3 + F.sub.3 - F.sub.3 +
 F.sub.4 - F.sub.4 - F.sub.4 - F.sub.4 - F.sub.4 +
 In the above table, F.sub.1, F.sub.2, F.sub.3 and F.sub.4 refer to the
 directions of movement of the control means of the operating units 26, 27,
 and a + sign implies a direction of movement to open flow passage across a
 threshold by raising a diaphragm portion off an associated threshold,
 whereas a - sign implies a direction of movement to shut flow passage
 across a threshold by pressing a diaphragm portion against an associated
 threshold.
 The second embodiment of the present invention shown in FIGS. 5-9 includes
 a three-port valve housing 30 having an upper valve chamber 31 and a lower
 valve chamber 32 provided in opposite parallel surfaces 30a, 30b of the
 valve housing. It appears from FIGS. 5 and 6 that the valve chambers are
 substantially circular in plan view and substantially bowl or plate shaped
 in side view.
 Extending like parallel chords across the upper valve chamber 31 are two
 valve seat means in the shape of weirs or thresholds 33 and 34 (FIG. 5).
 Interiorly provided in the valve housing 30 are well-like channels 35, 36
 (see FIGS. 8 and 9) that open in the valve chamber 31 radially outside the
 thresholds 33, 34, respectively, and communicate with respective ports A'
 and C' that are mutually aligned and diametrically opposed to each other.
 Evidently, the arrangement of the upper valve chamber 31 with its
 associated thresholds, channels and ports is similar to that of the upper
 valve chamber 11 of the first embodiment.
 The lower valve chamber 32 has but one valve seat means in the shape of a
 weir or threshold 37, excentrically extending like a chord over the valve
 chamber (FIG. 6). Interiorly provided in the valve housing 30 is a
 well-like channel 39 that opens in the valve chamber 32 radially outside
 the threshold 37 and communicates with a port D'.
 It appears from FIGS. 5 and 6 that the common axis of the channels 35 and
 36 and their associated ports A' and C' and the common axis of the channel
 39 and its associated port D' are perpendicular to each other, and,
 further, that the mutually parallel thresholds 33, 34 associated to the
 channels 35, 36 are perpendicular to the threshold 38 associated to the
 channel 39.
 Between the thresholds 33, 34 of the upper valve chamber 31 is provided a
 recess or cavity 41 (FIGS. 5 and 7) extending through the valve housing to
 open in the lower valve chamber 32 on the opposite side of the threshold
 38 relative to the channel 39. The width or the cavity equals the distance
 between the thresholds 33 and 34 (FIG. 5).
 Also in the lower valve chamber 32 there is provided, on the opposite side
 of the threshold 38 relative to the channel 39, a recess or cavity 42
 (FIGS. 6 and 7) extending through the valve housing to open in the upper
 valve chamber 31 between the threholds 33, 34.
 Together, the cavities 41 and 42 form a central space 43 extending through
 the valve housing 10 between the valve chambers 11 and 12 and having no
 communication with any of the ports A', B', C' and D' except across a
 corresponding threshold 33, 34, 3 and 38, respectively.
 Shown in FIGS. 7, 8 and 9 are an upper diaphragm 44 and a lower diaphragm
 45 adapted for cooperation with the thresholds 33, 34 of the upper valve
 chamber 31 and with the threshold 38 of the lower valve chamber 32,
 respectively. In order not to interfere with details of the valve housing,
 the diaphragms are shown spaced from the upper surface 30a and the lower
 surface 30b, respectively, of the valve housing 30. In operation, the
 diaphragms are clamped between respective upper and lower operating units
 46, 47 and the upper valve housing surface 30a and the lower valve housing
 surface 30b, respectively. Like in FIGS. 3 and 4, the upper operating unit
 46 schematically shown in FIGS. 7-9 is suitably of the first kind
 described in WO 97/17558 having two control means selectively movable in
 the directions indicated by arrows F.sub.1, F.sub.2 to press one portion
 each of a diaphragm 44 against a respective threshold 33, 34,
 respectively, and to raise corresponding portions off the thresholds. The
 lower operating unit 47 schematically shown in FIGS. 7-9 is suitably of
 the second kind described in WO 97/17558 having only one control means
 selectively movable in the directions indicated by an arrow F.sub.5 to
 press a portion of a diaphragm 45 against the threshold 38 and to raise
 that portion off the threshold.
 Now, by choosing different combinations or pressing and raising diaphragm
 portions, flow between the different ports may be established at least as
 appears from the following table:

Two-way communication between ports
 A' .rarw..fwdarw. D' C' .rarw..fwdarw. D' A' + C' .rarw..fwdarw. D' A'
 .rarw..fwdarw. C'
 F.sub.1 + F.sub.1 - F.sub.1 + F.sub.1 +
 F.sub.2 - F.sub.2 + F.sub.2 + F.sub.2 +
 F.sub.5 + F.sub.5 + F.sub.5 + F.sub.3 -
 In the above table, F.sub.1, F.sub.2 and F.sub.5 refer to the directions of
 movement of the control means of the operating units 46, 47, and a + sign
 implies a direction of movement to open flow passage across a threshold by
 raising a diaphragm portion off an associated threshold, whereas a - sign
 implies a direction of movement to shut flow passage across a threshold by
 pressing a diaphragm portion against an associated threshold.
 In the above description of the first and second embodiment of the present
 invention, the two valve chambers are provided in opposite parallel
 surfaces of the valve housing. However, the principles of the present
 invention involve a high degree of freedom as to the location of valve
 chambers. It would be quite possible, thus, to arrange two or more valve
 chambers in flat surfaces of a valve housing that are not opposite to each
 other provided only there is a possibilty to provide "a central space",
 such as a channel, between them. Consequently, even two or more valve
 chambers provided in the very same surface would be quite possible.
 A few examples of such possible arrangements will be briefly described with
 reference to FIGS. 10-19.
 In FIG. 10 is shown a perspective view of an embodiment including a valve
 housing block 100a having a substantially square cross section. One valve
 chamber 101 is provided in each of the four sides of the square cross
 section (FIG. 11). Each valve chamber has thresholds 102, 103 and between
 the thresholds a cavity 104 communicating with a corresponding cavity of
 each other valve chamber through internal intersecting channels 105, 106.
 Channels 107, 108 open in each valve chamber outside the thresholds 102,
 103 and communicate with respective upper and lower ports P1, P2.
 FIG. 12 shows a perspective view of an embodiment having one valve chamber
 101 in each of the six sides of a valve housing block 100b having the
 cross section of a regular hexagon. Internal, intersecting channels 109,
 110, 111 (FIG. 13) extending between opposed valve chambers connect the
 cavities 104 of all valve chambers 101. Channels 107, 108 open in each
 valve chamber 101 and communicate with respective upper and lower ports
 P1, P2.
 FIGS. 14 and 15 show a valve housing block 100c having two valve chambers
 101 in an upper flat surface. An internal channel 112 connects the
 cavities 104 of the two valve chambers, and ports P1, P2 communicate with
 a respective valve chamber as before.
 FIGS. 16 and 17 show a valve housing block 100d having two valve chambers
 101 in each of two opposed flat surfaces. Three internal channels 113,
 114, 115 interconnect all four valve chambers, and ports P1, P2, P3, P4
 communicate with a respective valve chamber.
 FIGS. 18 and 19 show an embodiment having a valve housing block 100e with
 two valve chambers 101 in each of two opposed flat surfaces and one valve
 chamber 101 in each of two opposed end surfaces. Three internal channels
 116, 117, 118 interconnect all six valves, and ports P1, P2, P3, P4, P5,
 P6 communicate with a respective valve chamber.