The invention relates to a self-closing valve with a head piece and an associated
valve seat housing, where a longitudinally movable valve piston is provided
5 in the head piece, which has a valve seal matching with a sealing surface of the
valve seat at its end facing the valve seat housing and a valve spindle is provided,
Which travels through to the head piece and the valve piston, whereby a
valve seat is provided on the head piece, which matches with a seal of the valve
spindle and a chamber seal is provided on the external surface of the piston
10 body, which is in contact with the sliding surface of the head piece.
The functioning of self-closing valves for a mechanical purge is based on Fig. 7
below, which represents the state of the art and which shows the cut section of
a unit, partly in open, partly in closed position. In the closed position shown in
15 the right half, the unit Lis in the idle condition. Both piston chamber A and valve
chamber B are under system pressure through an inlet port I. The chambers A
and B are separated from each other by a valve piston G and connected to
each other via a nozzle opening F. Since the pressurised piston area of the piston
chamber A is higher than the piston area of the valve chamber B, the valve
20 seat C is necessarily closed in this position. By pressing on the end of the valve
spindle J protruding from the unit, an opening of the servo valve D is created.
This reduces the pressure in the piston chamber A, whereby the piston chamber
A is emptied through a discharge port M and a spindle bore E. The end of
the spindle bore E is located in the pressure-free valve seat bore K which is ar-
25 ranged downstream of the valve seat C and in the valve seat housing H. Due to
the pressure still acting in the valve chamber B, the piston G floats and opens
the valve seat C. With the valve spindle J no longer pressurised, the servo valve
D returns to its closed position, whereby the piston chamber A is filled slowly
again by the pressurised valve chamber B through the nozzle opening F. When
30 the piston chamber A is fully filled, then the valve seat C is closed again. For the
separation of the piston chamber A, a seal N is provided on the piston. This is
designed as part of the piston G.
- 2 -
DE 39 25 873 A1 shows a piston, which is made of a flexible plastic and on
which, among other things, a sealing sleeve is formed identical to the material.
By doing so, the piston body must be so designed that it is dimensionally stable
to withstand the acting pressure load, while, on the other hand, the sealing
5 sleeve must be very flexible and resistant to wear. In fact, such a one-piece design
of the piston offers an advantage from the view point of manufacture and
cost; however, the choice of material is very limited due to the hygienic and mechanical
requirements . In conjunction with chemical effects, for example
through the use of industrial or raw water in flushes of WC and urinals, there
10 may be excessive requirement on the material used, which may adversely affect
the reliable operation of the valve.
But the seal for the separation of the piston chamber can also be designed as
an additional sealing element. In its simplest construction, the seal will be an 0-
15 ring. This type of sealing, however, has the disadvantage that the productionrelated
temperatures, which usually occur on the circumference of sealing ring
in the case of 0-rings, in fact cause a deterioration of the sealing effect typically
on the outside at the apex of the ring. In addition, a seal designed in the form of
an D-ring requires a higher preload, which causes a limitation of the sliding
20 properties of the piston (the so-called slip-stick effect; also known as "back sliding").
DE 592 627 C and DE 1 116 708 A show a piston having a sleeve on the piston
body. The sleeve is made of leather. However, such a construction with leather
25 sleeves are no longer common now-a-days, on the one hand, because it is difficult
to obtain leather of the required quality, and on the other hand, because the
requirements on drinking water hygiene no longer allow the use of leather in the
immediate vicinity of tap water.
30 Also DE 40 33 009 C2 and DE 296 10 805 U1 show a piston, where a sleeve is
arranged on the piston body. The sleeve is made of a different plastic than that
of the piston body. A disadvantage of these well-known solutions is that the
sleeve must be placed in the correct position during the manufacturing process
and its attachment to the piston body requires additional expenditure. In addi-
3 -
tion,the installation of the piston with respect to the mounting position of the
sleeve involves the risk of damage to the front edge of the sleeve, which can
result in deteriorated function of the piston.
5 DE 20 2005 004 177 U1 shows a piston, in which a so-called grooved ring with
a double-lip seal is used. The grooved ring can be made of a different plastic
than that of the piston body or can be made of an elastomer. As in the case of
the previously described sleeve, here also there is a need for correct positioning
during the assembly process as well as the risk of damage to the outer edge of
10 the lip seal, depending on the direction of assembly of the piston. Another disadvantage
is that grooved rings may tend to twist above a certain diameter-toheight
ratio and thus adversely affect a trouble-free installation. In addition, the
requirements on the grooved ring for a burr-free sealing edge are relatively
high.
15
Against this background, the problem underlying the invention is to create a
self-closing valve, which allows a trouble-free installation of the seal, resists the
chemical effects of the flowing medium and makes it possible to have an essentially
wear-free operation of the seal. According to the invention, this problem is
20 solved by designing the chamber seal as four-lip seal.
With the invention, a self-closing valve is designed, which allows a trouble-free
installation of the seal, because the design of the seal in the form of a four-lip
seal does not tend to twist because of its geometry. Rather, the selected seal
25 independently fits into the groove base with two of its four lips during its assembly,
while the other two lips protrude outside the groove for sealing. The two
protruding lips also provide an improved sealing effect. In addition, the four-lip
seal essentially makes a wear-free operation possible, as between the two lips
protruding from the groove, a reservoir of liquid is formed, which acts as a kind
30 of lubricant reservoir. At the same time, the production-related temperatures
exists between the lips and therefore does not affect the sealing effect.
- 4 -
Other further embodiments and designs of the invention are specified in the
other subclaims. An embodiment of the invention is shown in the drawing and is
described below in detail. Description of the figures:
5 Fig. 1 The cut section through the self-closing valve according to the invention
in the open position of the valve piston;
Fig. 2 The cut section through the self-closing valve shown in Fig. 1 in
the closed position of the valve piston;
Fig. 3 The cut section of a valve piston;
10 Fig. 4 The cut section of a head piece;
15
Fig. 5 The cut section of a valve seat housing;
Fig. 6 The cut section of a spindle;
Fig. 7 The cut section through the unit of a mechanical self-closing valve
according to the state of the art technology.
The self-closing valve selected as an embodiment of the invention has been
designed as a unit. It consists of a valve housing 1, in which a head piece 4 is
installed. At its one end, the valve housing 1 is provided with a threaded ring 7.
In the head piece 4, a movable piston valve 2 is installed. On the side opposite
20 to the threaded ring 7, the head piece 4 forms a valve seat housing 5. The selfclosing
valve has a valve spindle 6, which travels through the valve piston 2.
The valve housing 1 is provided with an inlet nozzle 10 and an outlet nozzle 12.
The inlet nozzle 10 has an inlet port 11; the outlet nozzle 12 has an outlet port
25 13. The valve housing 1 has an annular passage 15, where an insertion bore 14
is provided for the head piece 4 with valve seat housing 5 on the side facing the
outlet port 13. For securing the head piece 4, the threaded ring 7 is screwed
into an internal thread 16 in the valve housing 1.
30 The valve piston 2 is formed by a piston body 20. It has at its centre a collar 21,
which is provided with a valve seal 35 on its circumference. On the side facing
the outlet port 13 of the valve housing 1, the collar has a chamfer 23, which fits
in a sleeve 22, which is provided with windows 24. The sleeve 22 has a stepped
bore 31 inside, which extends up to the region of the collar 21. The stepped
- 5 -
bore 31 goes up to a through hole 30 for the valve spindle 6. The through hole
30 ends in a sealing chamber 29 with a spindle seal 36.
On the opposite side of the outlet port 13 of the valve housing 1, the valve pis-
5 ton 2 has an assembly opening 25 for a support body 32. The support body 32
has a through hole 33 for the spindle 6, which is coaxial to the through hole 30.
In the region of the assembly opening 25, a nozzle 26 is formed, which has an
insertion bore 28, to which a balancing hole 27 is adjoining. The insertion bore
. 28 accommodates a cleaning needle 37 inthe mounted condition.
10
Outside, the valve piston 2 has a chamber seal 34 on its external surface, which
serves for sealing against the head piece 4 and is inserted into an annular
groove, which has a rectangular cross-section. The chamber seal 34 is designed
as a four-lip seal. It consists of one basic body with four sealing lips.
15 Therefore, the chamber seal 34 has an "X"-shaped cross-section. As a result,
two sealing lips engage in the corners of the groove base in the mounted condition.
The other two sealing lips protrude from the annular groove partly, especially
as shown in Fig. 3. In the embodiment ofthe invention, the chamber seal
34 is manufactured from an elastomeric material. In particular, a thermoplastic
20 elastomer (TPE) is considered here. As a variation of the embodiment of the
invention, the chamber seal 34 can also be made of silicone.
The head piece 4 has an insertion bore 40, also called piston chamber, for the
valve piston 2 mounted movably. The insertion bore 40 has a sliding surface 45
25 for the chamber seal 34 of the valve piston 2. The head piece 4 is provided with
an inlet opening 41, which is aligned with the inlet opening 11 of the valve .housing
1 in the mounted condition. Adjacent to the inlet opening 41, window openings
49 are arranged on the circumference of the head piece 4. In its area opposite
to the valve seat housing 5, the head piece 4 has a valve seat 42, which
30 surrounds a valve bore 44 aligned with a through hole 43 for the valve spindle
6. The end of the head piece 4 opposite to the valve seat housing 5 has a projection
46, which has a stop face 4 7 outside for the threaded ring 7. Adjacent to
the stop face 47, the head piece 4 is provided with a seal48 outside.
- 6 -
The valve seat housing 5 is provided with a sealing face 50. The sealing face 50
matches with the valve seal 35 in the mounted condition. In the valve seat housing
5, a valve seat bore 51 is formed, into which the valve piston 2 can enter,
depending on the operating condition. The valve seat bore 51 leads to a
5 stepped bore 52, which has the sealing face 50. Adjacent to the sealing face 50,
a latch 55 is provided.
The valve seat housing 5 is equipped with undercut 58. Adjacent to the undercut
58, a collar 53 is provided, which has a stop face 54. On the collar 53, a
10 tongue 57 is designed, which is provided at its free end with a latch 55 that has
a stop face 56. In the mounted condition, the latch 55 engages in one of the
window openings 49. Outside, the valve seat housing 5 is sealed against the
valve housing 1 with the help of a seal 59.
15 The valve spindle 6 is designed as a hollow spindle. It is provided with a spindle
bore 61, which extends along the longitudinal centre line of the spindle 6. The
valve spindle 6 is also provided with a spindle bore 62 in the radial direction.
The valve spindle 6 is provided with a collar 60 outside. In addition, two seals
65 are provided at a distance from the collar 60 of the valve spindle 6 outside,
20 by which the spindle 6 is sealed against the head piece 4. For mounting the
valve spindle 6, a thrust ring 66 is provided outside in the embodiment of the
invention, so that the valve spindle 6 is installed in the head piece 4 movably
between the collar 60 and the thrust ring 66.
25 The valve spindle 6 is surrounded partly by a compression spring 63. In the
mounted condition, the compression spring 63 is supported, on.the one hand,
on the collar 60 of the valve spindle 6, and, on the other hand, on the valve piston
6, and, to be exact, on the support body 32.
30 The threaded ring 7 is provided with an external thread 70, which mates with
the internal thread 16 of the valve housing 1 in the mounted condition. It has a
bore 71, which receives the collar 46 of the head piece 4, partly in the mounted
condition. At its end facing the outlet port 13 of the valve housing 1, a collar 72
is provided, which is in contact with the stop face 47 in the mounted condition.
- 7 -
In the case of the invention-based self-closing valve, the valve spindle 6 is supported
on the valve seat 42 of the head piece 4 with the help of collar 60
through the valve seal 64 in the closed position of the valve piston 2 (see Fig.
5 2). In this position, the valve seal 35 of the valve piston 2 is in contact with the
sealing surface 50 of the valve seat housing 5. Similarly, both the outsideprotruding
sealing lips are in contact with the sliding surface 45 of the head
piece 4 and thus separate the piston chamber that is formed on the side of the
valve piston 2 opposite to the outlet port 13 in the insertion bore 40 from the
1 0 valve chamber that is formed on the side of the valve piston 2 facing the outlet
port 13 in the insertion bore 40. If the valve spindle 6 is actuated now by pressing
in the direction of the outlet port 13 and against the force of the compression
spring 63, the valve seal 64 of the valve spindle 6 lifts from the valve seat 42 on
the head piece 4. This allows the water in the pis!on chamber to enter the spin-
15 die bore 62 and leave the piston chamber through the other spindle bore 61.
20
This leads to a pressure relief for the piston chamber, causing the valve piston 2
to move from its original position in the direction of the threaded ring 7, by which
the seal 59 lifts from the sealing face 50. The water in the inlet port 11 can now
flow past the valve piston 2 in the direction of the outlet port 13.
On releasing, the valve spindle 6 it returns to its initial position under the influence
of the compression spring 63, so that the valve seal 64 is back in contact
with the valve seat 42. The outflow of water from the piston chamber is thus
stopped. At the same time, water flows into the piston chamber through the
25 through hole 30 and the insertion bore 28 of the valve chamber. Under the influence
of rising water pressure in the piston chamber, piston 2 is pushed in the
direction of the outlet port 13 until the valve seal 35 again comes into contact
with the sealing face 50. The water supply from the inlet port 11 to the outlet
port 13 is thus stopped.
30
In the case of the invention-based self-closing valve, the sealing essential for
the reliable operation of the valve between the piston chamber and valve chamber
takes place through the chamber seal 34 designed in the form of a four-lip
seal. As compared to conventional seals on valve piston of self-closing valves,
- 8 -
this is distinguished by an improved sealing effect due to the double sealing lips
in the outer region of the piston. In addition, there is reduced wear, since a lubricant
reservoir exists between the sealing lips, which also produces an improved
sliding characteristic. Also the preload of four-lip seal is low, resulting in
5 lower friction of the seal on the wall of the head piece 4 and thus in an improved
sliding characteristic. Another advantage of the chamber seal 34 designed in
the form of a four-lip seal is that the production-related temperatures, which
usually occur in the case of 0-ring seals on the circumference of the seal, which
is in fact typically found on the outside at the apex of the ring, is found between
10 the sealing lips protruding outwards in the case of the four lip seal and therefore
not in the region of the sealing surface. The inevitable temperature therefore
has no influence on the sealing effect. In addition, the material can be chosen
depending on the flowing liquid.
·-
' ' - 9 -
Claims
1. A self-closing valve with a· head piece (4) and an associated valve seat
housing (5), where a longitudinal1ymovablevalve piston (2) is provided in
5 the head piece (4), which has a valve seal (35) matching with a se_aling surface
(50) of the valve seat (5) at its end facing the valve seat housing (5)
and a valve spindle (6) is provided, which travels through to the head piece
(4) and the valve piston (2), whereby a valve seat (42) is provided on the
head piece (4), which corresponds to the valve spindle (6) with a seal (65)
10 and a chamber seal (34) is provided on the external surface of the piston
body (20), which is in contact with the sliding surface (45) of the head piece
(4), characterised in that the chamber seal (34) is designed as four-lip seal.
2. The self-closing valve according to claim 1, characterised in that the chamber
seal (34) is made of an elastomeric material.
15 3. The self-closing valve according to claim 1, characterised in that the chamber
seal (34) is made of silicone.
4. The self-closing valve according to claim 1 or 2, characterised in that the
chamber seal (34) is made of a thermoplastic elastomer.
5. The self-closing valve according to any one of the above-mentioned claims,
20 characterised in that the chamber seal (34) consists of a basic body with
four sealing lips.