Note: Descriptions are shown in the official language in which they were submitted.
CA 02555045 2007-06-07
1
Air Flow Control Valve
Field of the invention
This invention relates to a diaphragm operated air flow control valve of the
type typically used in the dust collector industry. The valve of the invention
will be
suitable for use in that industry, but it is to be understood that the valve
of the
invention can be used in other applications as well.
Background of the invention
Air flow control valves used in the dust collection industry have a series of
reasonably specific design constraints which they must meet in order to
operate
effectively. For example, typically the valves have inlets and outlets
arranged at 90
to each other, the valves are typically electronically controlled, and the
supply and
outlet pipes which lead towards and away from the valve are typically either
20mm,
25mm or 45mm in diameter.
Typically these valves have a valve closure member mounted to a diaphragm
and by controlling the pressure on opposite sides of the diaphragm the valve
can
either be opened or closed. The pressurised air supply provides the necessary
pressure for controlling the valve and a bleed arrangement is provided for
supplying
air under pressure to opposite sides of the diaphragm.
Since these aspects of the valves are well-known, they need not be described
in this document in any great detail.
There are important performance characteristics which such valves must meet
in order to be competitive in the industry. For example, the valves must open
rapidly
and there must be a minimum pressure drop across the valve when the valve is
open.
In addition, the valves should be relatively easy to manufacture, assemble and
install,
and maintenance of the valves should be possible without removing the valve
body
from the equipment onto which it has been installed.
CA 02555045 2007-06-07
2
Summary of the invention
According to one aspect of the invention there is provided a valve body and
cover, the valve body including a threaded portion to engage a mating threaded
portion on the cover, the body and the cover having respective engagement
members
which are adapted to engage each other in use, the members being positioned so
that
the cover, when threaded onto the body, will rotate a necessary number of
turns to
secure the cover to the body to a predetermined torque, indicated by the
engagement
members engaging each other preventing any further tightening, the engagement
members not engaging or contacting until the predetermined torque is reached;
an
aperture located in the cover and the body so that once the engagement members
are
engaged, the apertures are aligned so as to receive a locking means; and a
pressure
activated pawl included in the body, with the cover having a recess or
aperture,
whereby when the valve is pressurized the pawl moves into the recess thereby
locking the cover and the body together until depressurized.
Brief description of the drawings
Further features of the invention will be made apparent from the description
of the embodiments thereof given below by way of examples. In the description
references are made to the accompanying drawings, but the specific features
shown
in the drawings should not be construed as limiting on the invention.
Embodiments are described with reference to the following drawings in
which:
CA 02555045 1999-12-22
3
Figure 1 illustrates an exploded cross-sectional side view of an air flow
control valve ;
Figure 2 illustrates an enlarged cross-sectional side view of the bowl portion
of the valve body of Figure 1;
Figure 3 illustrates a perspective view of a valve similar to Figures I and 2
with different connecting
portions and with the cover removed from the body portion;
Figure 4 illustrates an end view of the bowl portion of the body of the valve
shown in Figure 3;
Figure 5 illustrates an exploded view of another valve body and cover;
Figure 6 illustrates the cover and body of Figure 5 in an assembly;
Figure 7 illustrates an exploded perspective view of valve components to
construct a valve similar to that
of Figures 5 and 6;
Figure 7A illustrates a perspective view of the valve body and diaphragm of
Figure 7;
Figure 8 illustrates an exploded view of an operator or pilot valve for use
with the cover of Figures 5, or 6;
Figure 9 illustrates a cross section of the exploded pans of another operator
construction;
Figure 10 illustrates a cross section of the operator of Figure 9 in assembled
condition;
Figure I1 illustrates a plan view of an arrangement to lock a cover relative
to a valve body when
pressurised;
Figure 12 illustrates a right side elevation of the valve of Figure 11;
Figure 13 illustrates a cross section through the valve of Figure 11 through
the plane BB;
Figure 14 illustrates a detail of the right hand side of the cross section of
Figure 13;
Figure 15 illustrates an exploded view of a pilot valve or operator assembly
similar to that of Figures 9 and
1o;
Figure 16 shows the pilot valve or operator assembled from the parts of Figure
15;
Figure 17 illustrates a part cross section through the pilot valve or operator
of Figure 16, with the pilot
valve or operator in the closed condition; and
Figure 18 illustrates a part cross section through the pilot valve or operator
of Figure 16, with the pilot
vaive or operator in an open condition.
Detailed description of the embodiments
Illustrated in Figure 1 is a flow control valve 2 which includes a valve body
10 having a bowl portion 12
and a cap portion 14, which in use is mounted to the bowl portion 12 with an 0-
ring seal 13 to seal the under side
of flange 130 of cap portion 14 with a sealing rim 132 at the top of the bowl
portion 12. The cap portion 14 will. in
use, hold a diaphragm assembly 16 to the body portion 12. The valve 2 is
controlled by a solenoid operated plunger
assembly 18 which includes a plunger 20, compression spring 22 and a retaining
clip 24. These components are
well known in the art and need not to be described herein in any detail.
The diaphragm assembly 16 has a flexible circular diaphragm 55 which has a
valve closure member 20
mounted thereto by means of a fastener 22 and backing plate 24. The diaphragm
55 has a bleed passage 26
therethrough (see also bleed passage or hole 26 in Figure 7A), through which
pressure differentials on opposite
sides of the diaphragm 55 are equalised. A compression spring 28 urges the
diaphragm away from the cap portion
14. The plunger 20 has a rubber cap 30 on its lower most end which is adapted
to seal with a nozzle 32 which in
use is mounted to the cap portion 14.
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4
The bowl portion 12 has an inlet 34 and an outlet 36 both of which are in flow
communication with an
internal cavity 38. The internal cavity 38 is of a circular or bowl shaped
configuration. A valve seat 40, which is
coaxial with and surrounds the outlet 36, is formed on the bowl portion 12.
The valve seat 40 is located on the
upper or distal end of a tubular pedestal 42 which surrounds the outlet 36.
The pedestal 42 serves to lift the valve
seat 40 adjacent the under side of the diaphragm assembly 16 which will be
mounted against an annular seat 44
formed on the body portion.
Turning to Figure 2 of the drawings, the body portion 12 is shown in more
detail. The configuration of the
body portion 12 achieves significant efficiencies for the valve.
The inlet 34 of the body portion 12 has a centre line 45 which, when the body
portion is oriented, as
shown in Figure 2, with the centre line 45 horizontal and the outlet 36 facing
downwardly, the valve seat 40 is
located below the upper most edge 47 of the inlet 34. In other words, the
valve seat 40 is relatively close to the
centre line 45 of the inlet 34. In the arrangentent shown in Figure 2, for
example. where the inlet diameter 34 is
approximately 24mm, the dimension "d" is approximately 9mm which is
significantly less than the applicant's prior
art valve arrangements which is approximately 20mm. The dimension between the
diaphragm seat 44 and the valve
seat 40 has also been increased. In the applicant's prior valve that
ditnension was approximately 6mm whereas in
the present embodiment that dimension is approximately 9mm. However, it is
believed that it is the lowering of the
valve seat 40 in relation to the inlet port centre line which has
significantly improved the efficiency of the valve.
The effect of these dimensional changes is that when the valve is open, a
relatively large opening is achieved
between the diaphragm and the valve seat, and the valve seat is also located
within the direct flow path of air
flowing from the inlet to the outlet. This ensures a significantly lower
pressure drop across the valve.
In addition to lowering the valve seat the applicant has also increased the
diameter of the annular space 46
around the pedestal 42. This has been achieved by an increase in the diameter
of the body portion 12. This larger
bowl area allows for a straighter flow path of high pressure air across the
valve seat 40 and into the outlet 36 when
the valve is open. Furthermore, this arrangement provides a higher static
pressure recovery (due to lower air
velocity around the bowl) inside the bowl. The higher the static pressure
inside the bowl, the better the flow across
the seat when the valve is open.
These new configurations in the valve body have helped to achieve an
approximately 40% flow
improvement (Kv) against applicant's own prior art valve of similar external
dimensions. The attached Table I sets
out a comparison of a valve of the present embodiment (being those marked with
a suffix "-3" in column 1) and
certain of the applicant's comparable prior an valves (being those with a
suffix "std" in column 1).
Clearly, the applicant does not in any way wish to be bound to any of the
dimensions or ratios listed in
Table I but those dimensions indicate certain of the differences between the
prior art valves and the valve of the
present embodiment which have gone towards achieving this improvement in flow
performance.
One difference in particular is that the column entitled Bowl Area/Seat Area
indicates that for the valves
embodying the invention, namely those with a "-3" suffix that this ration is
in the range of 2.5:1 to 4.5:1 and more
particularly in the range of 3.2:1 to 3.6:1.
The FS, DD and T are letter codes representing for the inlet and outlet
configurations available in the
industry. The FS valves generally have a structure where the inlet has a
tubular connection with a flange
CA 02555045 1999-12-22
surrounding its end, while the outlet has an unthreaded unflanged tubular
construction. The DD valve has male
threaded inlet and outlet which cooperates with a gland nut and frusto-conical
seal as iliustrated in figure 7. The T
valve has an inlet and outlet with female threads as illustrated in figures 1,
2 and 1 1 through to 14.
TABLE I:
YM1ri :} ~ '. $/~N~~:: Sse1t wl"BO~A[l4 Sat~ltit : B~1.: 4ntdt = X - ~
~ - iM Y
. '. ' .wr :. - ..._ .,~ .. :.. l
s!F . ~`~ r 1..z .
a1M~ ~~ _ tt1117 .
-
2SFS-3 35.00 42.00 962.11 77.00 3271.18 0.29 3.40 14.30 39.40 13.71
25FS std 31.50 42.00 779.31 64.00 1831.55 0.43 2.35 30.80 39.40 =28.17
20FS-3 27.50 32.50 593.96 60.00 1997.85 0.30 3.36 9.00 26.00 15.38
20FS std 23.00 27.40 415.48 51.30 1477.28 028 3S6 19.50 2520 47.38
2000ti3 27.50 32.50 593.96 60.00 1997.85 0.30 3.36 9.00 256.0 14.00
201-3 27.50 32.50 593.96 60.00 1997.85 0.30 3.36 9.00 23.90 12.34
20T,DD-std 20.50 25.80 330.06 50.80 1504.04 0.22 4.56 1520 23.00 -16.09
45FS-3 55.00 63.50 2375.83 120.00 8142.80 029 3.43 15.00 46.00 20.00
45FS std 53.50 63.50 2248.00 95.50 3996.10 0.56 1.78 37.90 46.00 -5.80
451,DD std 50.80 59.00 2026.83 95.50 4429.05 0.46 2.19 37.80 40.40 =10.65
5 Notes for Table I
Seat Area Based on ID column- Seat area is based on ID.
Bowl Area Column- Bowl area is based on (bowl ID minus seat OD).
Inlet Centreline to seat height column- Height from inlet port centreline to
diaphragm flange.
Inlet port diameter column-Only 25FS-3 dimension quoted against 25FSrT/DD-3
row.
% port dia exposed column-Based on % of port diameter(not area) exposed above
body seat.
Other improvements of the valve are that the cap portion 14 has a male threads
48 which engage in female
threads 50 formed in the body portion. This allows the cap portion 14 to be
screwed onto and off the body portion
for quick assembly and maintenance. The plunger assembly, likewise, is simply
fitted to the cap portion by the clip
24 which engages in a groove 52. The cap 14 includes a hexagonal formation 14'
to allow a spanner to engage it
and also provides gripping formation 14" so that tightening by hand can be
performed.
It will be appreciated that the valve seat 40 could be lowered even closer to
the centre line 45 of the inlet.
This could be achieved by, for example, increasing in the thickness of the
valve closure 20, thereby bringing the
contact face of the valve closure member 20 closer to the valve seat 40. Also,
the increased bowl diameter has the
effect of increasing the diameter of the diaphragm 55 allowing more movement
of the diaphragm 55 and therefore
permitting the valve seat 40 to be located a greater distance away from the
valve closure inember 20 than is the case
with small diameter diaphragms.
It will be appreciated that maintenance of the valve can take place in a
relatively simple fashion. To
maintain the valve after it has been installed onto equipment the cap portion
14 is simply screwed off the body
portion 12 allowing the diaphragm assembly 16 to be removed and replaced as
necessary. The plunger assembly 18
can, similarly, be removed from the cap portion by releasing the clip 24. This
is a simple operation and allows for
far quicker maintenance and inspection than is the case where a series of
bolts or screws are used to hold down the
cap and the plunger assembly.
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It will be appreciated that the simplicity of the valve also enables the valve
to
be easily and rapidly assembled during manufacture. In addition, the
simplicity of the
design has significantly reduced the number of parts of the valve and this has
therefore reduced the cost of the valve.
Illustrated in Figures 3 and 4 is a valve body similar to that of Figure 2,
except that there are male threaded connections 54 to allow connection to the
inlet 34
and outlet 36. It will be noted that the valve of Figure 2 has two female
connections.
Other valves connections could be provided such as flanges clamped or bolted
fitting
arrangements.
Illustrated in Figure 5 is an exploded view of a valve 2A having a cover 14A
and body 10A similar to valve 2, cover 14 and body 10 of Figure 1. Many of the
components illustrated in previous Figures are not illustrated in Figures 5
and 6 to
provide better clarity. The cover 14A has a male thread 48A whilst the body
10A has
a female thread 50A which mates with the male thread 48A.
The cover 14A and body 10A differ from the cover 14 and body 10 of Figure
1 by the presence of a radially extending portion 100 on the cover 14A and a
similar
shaped radial extension 102 on the body 10A. The extension 100 terminates in a
face
104 which can engage protruding boss 106 on body 10A. The height of the
extension
100 and the pitch of threads 48A and 50A are designed and arranged so that the
cover 14A will be tightened onto the body 10A after 1'/z turns of the cover
14A. Thus
to connect the cover 14A to the body 10A the thread 48A has to begin on cover
14A
in the vicinity of the face 104 whereas the thread 50A needs to begin at a
location
diametrically opposite to protruding boss 106. In this way after the first
half turn with
the threads engaged, the lower most portion of face 104 will pass close to,
but not
make contact with, the upper surface 108 of protruding boss 106. The
protruding
boss 106 is of a depth or height equal to the pitch of the thread 50A or 48A.
Thus
after one further complete turn the underneath surface of extension 100 and
face 104
will be at the same level as the upper surface of extension 102 and the face
104 will
be prevented from moving further in a tightening direction by means of the
protruding boss 106.
In this way, the cover 14A can not be overtightened onto the body 10A. The
face 104 and boss 106 being highly visible allows a service person or fitter
of these
CA 02555045 2007-06-07
6a
valves to know if the valve cover 14A has been appropriately tightened.
If desired, as illustrated in Figure 5 and 6, an aperture 110 can be provided
through the extension 100 in the vicinity of face 104 and an aperture 112 can
be
provided in the extension 102 in the vicinity of protruding boss 106, so that
once the
face 104 and boss 106 are contacting (as in Figure 6) the apertures 110 and
112 are in
alignment. This allows a pin, or a cable tie or other locking apparatus to be
threaded
through apertures 110 and 112 and secured to prevent the cover 14A from
unwinding
from the valve body l0A unintentionally. To an extent it also ensures that the
valve
has not been tampered with since the last servicing. The latter especially is
possible if
the locking means is of the sort that needs to be destroyed to be removed such
as a
cable tie or a frangible pin.
In the embodiment of Figures 5 and 6 the face 104 and boss 106 are provided
in an offset location compared to the circumference of the cover 14A. If
desired
similar bosses can be provided within the circumference of the body 10A,
however to
do this may require the wall thickness 115 (see Figure 5) to be increased in
order to
allow sufficient bearing area of face 104 and boss 106 and to allow for some
locking
mechanism if desired.
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It can be seen in Figure 5 that the threads 50A and 48A have axially
extending grooves 120 and 122 on the body 10A and grooves 124 on the cover
14A.
The grooves 120, 122 and 124 ensure that once the cover 14A is unscrewed
relative
to the body IOA and the underneath flange 130 of the cover 14A breaks contact
with
an 0-ring seal (not illustrated) situated on top of rim 132, any gas pressure
inside the
valve body 10A will be exhausted through the grooves 120, 122 and 124.
Clearly, the
grooves need only be formed on any one of the valve body 10A or cover 14A,
however, if desired, they can be located on both as is illustrated in Figure
5. It is will
be readily understood that this feature of one or more grooves 120, 122 or 124
is a
desirable safety feature, and need not be present for the working of the
valve.
Illustrated in Figure 7 and 7A is a valve construction similar to that of
Figures 3 and 4, with a cover arrangement similar to Figure 5 and 6. In Figure
7 like
parts to those of previous Figures have been like numbered, and their function
and
purpose need not be described further. As can be seen from Figure 7 the flow
control
valve 2B has a valve cover 14A, 0 ring seal 130, spring 28 and diaphragm 16.
The
body l0A has inlet and outlet male threaded connections 54 which cooperate
with
frusto-conical seals 54A and gland nuts 54B which together form a sealed
connection
with a conduit passing through them once gland nut 54B is secured to threads
54 thus
compressing the seals 54A to seal against outer surface of the conduit.
Illustrated in Figure 7 is a pin 112A which is sized to fit through circular
apertures 110 and 112 in the cover and body respectively when the cover 14A is
screwed onto the body 10A and the apertures I 10 and 112 are aligned.
This alignment is assured due the arrangement of the threads 50A and 48A,
and the cooperative interaction of boss 106 and shoulder 104 which engage each
other preventing further tightening of the cover 14A on body 10A as described
in
relation to Figures 5 and 6.
As illustrated in Figure 7A the valve body 10A includes an extension 100
similar in purpose to the extension 100 of Figure 5, except that the extension
100 of
Figure 7A is of a shape which allows the valve body 10A to have an axis of
symmetry on either side of a plane AA which passes through the inlet, the
outlet and
bowl portion. The boss 106 also has a shape allowing it to be readily die
cast. The
boss 106 is sized relative to the threads 48A and 50A and the face 104 so as
to
CA 02555045 2007-06-07
7a
function in the same manner as boss 106 of Figures 5 and 6. It should be
appreciated
that in addition to bosses other protruding formations which can extend
laterally or
axially relative to the valve body or cover, such as lugs, faces, pins or
combinations
of these may also be used. Turning now to Figure 8 there is disclosed a valve
operator 200 for use with the covers of Figures 5 and 6.
The operator 200 has a base 202 which can be made from a plastics material
or alternatively manufactured from any suitable material such as steel, brass,
aluminium, etc. If a plastics material is desired, preferably nylon 6 or glass
filled
nylon is utilised. However, if the operator 200 is to be used in a high
temperature
environment, the base 202 may need to be made of a material of better heat
resistance
than plastics and thus a metal or other heat resistant material will be more
appropriate.
The base 202 has a generally planar undersurface 204 to provide a sealing
surface in conjunction with an 0-ring (not illustrated) which would be
positioned
inside a groove 140 as illustrated in Figures 5, 6 or 7.
When used with the embodiment illustrated in Figures 5 to 7 the connecting
means between the base 202 and the cover 14A or 14B is by means of a threaded
tubular portion (not illustrated in Figure 8 but see similar feature being
item 410 in
Figures 9 and 10) which extends downwardly from base 202 and engages the
threaded port 142 in covers 14A of Figure 5 and 6. This is a preferred
arrangement
and other mechanisms could be used to
CA 02555045 1999-12-22
8
connect the base 202 to the port 142 in a sealed atrangement. Such other
mechanisms can include bayonet fittings;
providing the base 202 with a female thread to engage a male threaded portion
surrounding the port 142: or other
appropriate arrangement can be used.
The base 202 as illustrated in Fig 8 includes an upwardly extending
circumferential skirt 206 which serves
the purpose of surrounding the base of a silencer 208 when located on the base
202. Skirt 206 is optional and is
provided in this embodiment ntainly for aesthetic reasons. If desired, the
base 202 can be made from a simple plate
construction (that is without skirt 206) having an upper and lower generally
planar surface (see base 202 A in
Figures 9 and 10).
In the centre of the base 202 in Fig 8 is a valve seat 210 having a generally
conical shape and providing a
port 212 which can be sealed by means of a valve member 214 at the base of a
plunger 216.
Upwardly extending from the base 202 are four support walls 218 which have
spaces 220 between
respective support members 218. The spaces 220, when the operator 200 is
assembled, effectively form exhaust
ports so that any air passing through the valve seat 210 when the valve member
214 is not engaging the valve seat
210, will pass through the port 212 and out to atmosphere via the spaces 220.
The valve stem 216 is concentrically held over the valve seat 210 by means of
a ferrule tube 222. The
ferrule tube 222 is assembled to the base 202 by first inserting the
compression spring 224 and the plunger 216
coaxially adjacent thereto. The ferrule tube 222 is then pushed into
connection with the base 202, so that the rim of
the base 226 of ferrule tube 224 when pushed towards base 202, engages the
angular surfaces 219 of each member
218, thereby pushing the members 218 radially outward from the central axis of
the base 202. The members 218
continue to move outward until the base 226 of the ferrule tube 222 is located
within a groove 230 which holds the
base 226 and prevents it from moving either towards or away from the base 202.
Once the base 226 of the ferrule tube 222 is located in line with the groove
230 on each member 218, the
members 218, by their relatively elastic nature, move radially inward relative
to the central axis of the base 202,
thus locking fetrule tube 222 in position. The groove 230 and support members
218 keep the base 222 from
moving relative to the seat 210 in any direction, ensuring that the ferrule
tube 222 will apply an appropriate spring
tension by means of spring 224 to force the plunger 216 to the closed position
against the expected pressure which
can be applied by gas pressure within the valve body, which bears against
valve member 214 via port 212.
The operator 200 has its valve seat 210 normally closed due to the compression
of spring 224. A solenoid
or coil (not illustrated) when activated. will pull the plunger 216 away from
seat 210 against the bias of spring 224.
The ferrule tube 222 is received in the solenoid, which is secured to the
ferrule tube 222 by means of a circlip (not
illustrated) around the groove 232 in the iron top and shading ring 232A.
The silencer 208 is a ring of porous plastic or could be of some other porous
material such as sintered
bronze which would be particularly useful in high temperature environments.
The silencer 208 is an optional
feature of the operator 200 as the silencer 208 is not required for the
operation of the operator 200. However, with
current noise abatement regulations and occupational health standards, the
silencer 208 can be applied to the
operator 200 by simply concentrically locating the silencer 208 around the
outside surfaces of each of the support
members 218 and locating the lower portion 240 of silencer 208 inside the
annular space located between the
outwardly facing side of support members 218 and the inwardly facing surface
of annular skirt 206.
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9
If desired, the lower portion 240 of silencer 208 can have a male thread
formed thereon, with a female
thread being formed on the inwardly facing surface of skirt 206. If such
threads were provided in portion 240, then
the silencer 208 could be screwed into the base 202 by means of threads on
annular skirt 206 and lower portion
240. This will permit the silencer 208 to have a tapered inner surface 242 so
that as the silencer 208 is screwed into
the base 202, the surface 242, if tapered, will force the support members 218
towards the central axis of the base
202. This will positively urge the support members 218 towards the centre of
the base thus securing the ferrule tube
222 into the annular groove 230. Even without such threading and tapering, the
silencer 208 helps to prevent the
support members 218 from moving in a radially outwardly direction thus
preventing them from disengaging from
the base 226 on ferrule tube 222.
In another embodiment, an operator 400 is illustrated in Figures 9 and 10.
Like parts of the embodiment of
Figures 9 and 10 compared to Figure 8, have been like numbered and their
function need not be repeated, as
reference can be had to the previous description. In this embodiment the
operator 400 is formed with a base 202A
which interconnects, without means of a ferrule tube, to a solenoid body 401.
That is the base 202A and the
solenoid body 401 alone provide the means to slidably retain the plunger 216A
in position and permit it only to
move in an axial direction towards and away from the valve_seat 210A. In this
embodiment an iron top and shading
ring 401 A is provided within the solenoid body 401.
Four support members 2I8A terminate in a barb formation 402 so as to engage
flange 403 formed with or
attached to the casing of solenoid body 401. The operator 400 of Figs 9 and 10
has like parts to the valve 200 of
Fig B. These like pans are like numbered and end with the letter "A".
In Figure 9 and 10, there can be seen the threaded tubular spigot 410 (not
illustrated in Fig 8) which allows
for threaded attachment to the threaded port 142 of Figs.5 to 7.
Illustrated in Figures 15 to 18 is another operator 400A similar to that
illustrated in Figure 9 and 10. Like
parts in Figures 15 to 18 when compared to Figures 8 to 10 have been like
numbered, and further description of
their function is not required as reference can be had to the previous
description.
The operator 400A includes a solenoid body 401 which has four equi-spaced
retaining formations 403A
which extend radially away from a cylindrical portion 403B at the base of the
solenoid body 401. Each retaining
formation 403A includes a groove 403C and an tapered lower extremity, the
purpose of each these be described
later.
The support walls 218A are similar to those in Figures 9 and 10, except that a
barb like structure 402A is
outwardly directed and the four equi-spaced support walls 218A are of a width
to fit into the spaces between the
retaining formations 403A.
A retaining ring 500, such as circlip, cable tie, twisted wire or other
appropriate retainer can be used to
retain all the components securely together as illustrated in Figure 16. As
can be seen in Figure 16, when
assembled, the support walls 218A fit between the retaining formations 403A
until the lowermost part of the barb
402A is at the upper most wall or part of the groove 403C. Once in this
position the circlip 500 can be positioned in
the groove 403C thus keeping all the components locked together. The tapered
lower extremity of the retaining
fotmations 403A aid in the positioning of the circlip 500, by allowing the
circlip 500 to be expanded due to it being
CA 02555045 1999-12-22
pushed along the tapered extremity in the divergent direction. Once circlip
500 is aligned -with groove 403C, the
circlip will enter the groove 403C and trap the barb 402C into the position
illustrated in Figure 16.
As can be seen in Figure 17 and 18 when the operator 400A is closed the spring
224A biases the plunger
216A to the closed position sealing the valve seat 210A and port 212A. When
the solenoid in solenoid body 401 is
5 activated as in Figure 18, the plunger 216A is retracted compressing the
spring 224A between the plunger 216A
and iron top and shading ring 401A, thereby opening the port 212A to
atmosphere. Ilis allows air to escape
through spaces 220A (see Figure 16) between the support walls 218A and
underneath the retaining formations
403A. thereby forcing the diaphragm to move the valve seat in the valve body
to the open position.
Illustrated in Figures 1 i through to 14 is an alternative mechanism to lock
the cover 14C on to a valve
10 body lOC when the valve body lOC is under pressure. The arrangement can be
seen more clearly in Figure 14
whereby a spring biased paw1310 is situated in a cylinder 3121ocated in the
valve body l OC. As can be seen from
Figure 10, the cylinder 312 is located offset from the circumference of the
cover 14C.
As is illustrated in Figure 12. the cover 14C operates in a similar fashion to
that of Figures 5 to 7 in that a
protruding boss is provided on the cover 14C which engages a protruding boss
or protrusion 316 on body IOC.
The cylinder 312 is connected by a passage 318 to the main volume of the valve
body IOC. The cover 14C
will be correctly positioned onto the valve body IOC, once the cover 14C is
correctly tightened, that is when
protruding boss 314 engages protrusion 316. When boss 314 and protrusion 316
engage, this will cause an
alignment of aperture 320 over pawl 310. When the aperture 320 is directly
above the pawl 310 and pressure is
applied to the valve body I OC, air travelling through passage 318 gains
access to the cylinder 312 thereby forcing
the pawl 310 against the bias of compression spring 322 through the aperture
320 in cover 14C. Thus the cover
14C cannot be released until such time as pressure is released from the valve
body lOC. Once pressure is released,
the compression spring 322 will force the pawl 310 back into cylinder 312,
thus allowing the cover 14C to be
removed from the body IOC.
Clearly, many variations may be made to the above described embodiments
without departing from the
scope of the invention. The embodiment shown in Figures 3 and 4 depicts an
atrangement in which the inlet and
outlet have external threads 54 thereon to allow for a different type of
connection arrangement to the air conduits.
However, the arrangement shown in Figures 3 and 4 employ the same valve seat
configuration which, it will be
noted from Figure 4, is located below the upper edge 46 of the inlet.
It will be understood that the invention disclosed and defined herein extends
to all alternative
combinations of two or more of the individual features mentioned or evident
from the text or drawings. All of these
different combinations constitute various alternative aspects of the
invention.
