EP0634529A1 - Pipe separator - Google Patents

Abstract

In the case of a pipe disconnector having a throughflow housing (1) which exhibits a supply line and a discharge line (2,3) and in which a central chamber (5) is arranged between a spring-loaded supply valve and a spring-loaded discharge valve, the two spring-loaded valves are each equipped with a valve disc (4) and a cage (41) which exhibits a guide part (43) for fixing it radially in the throughflow housing (1) and a seat collar (42) for fixing it axially therein, the end surfaces of the two cages (41) being designed as a valve seat. In order to be able to use identically designed parts for the two spring-loaded valves, which exhibit different loading springs (44,45), without it being possible to confuse the two non-return valves and use them incorrectly, the throughflow housing (1) is designed such that in each case only the supply valve can be installed into the supply line (2), and only the discharge valve can be installed in the discharge line (3), of the central chamber (5). <IMAGE>

Description

The invention relates to a backflow preventer with a flow housing having an inlet and a discharge, in which a spring-loaded inlet valve and a spring-loaded outlet valve as well as a central chamber are arranged between the two valves and the two spring-loaded valves each have a valve disk and a cage for radial Fixation in the flow housing has a guide part and for axial fixation a seat collar, the end faces of which are designed as a valve seat.

System separators of the above type are known, for example, from EU-A 00 84 754 and DE-A 28 54 003. With the system separator, the fluid normally flows through the valve from the inlet side through a spring-loaded check valve into the middle chamber and from there through a second spring-loaded check valve to the outlet side. If the pressure at the outlet of the system separator increases, for example due to damage in the downstream system, so that the medium is pressed back, or the pressure on the inlet side of the system separator decreases, for example due to a pipe break, so that back suction occurs, both have If the flow is reversed, this creates a negative pressure difference. To prevent the flow from reversing, the two spring-loaded check valves close If the pressure on the inlet side of the system separator decreases, for example due to a pipe break, so that there is a back suction, both cases result in a reversal of the flow, since a negative pressure difference arises. In order to prevent a reversal of the flow, the two spring-loaded check valves close at a certain positive pressure difference. For safety reasons, the middle chamber is equipped with a relief valve in order to open a ventilation opening in the event of damage and also to drain the medium through an outlet opening. If the drain check valve is leaky, the middle chamber pressure will increase with a negative pressure difference, i.e. with a pressure higher at the drain than at the valve inlet. The relief valve opens due to the increased pressure in the middle chamber and clears the way for the medium to be pushed back into the relief opening. The relief valve only closes when a pressure difference at the inlet of at least 0.14 bar compared to the middle chamber is reached. In order for this pressure to be reached without a flow occurring beforehand, the inlet check valve is equipped with a correspondingly strong spring, while the outlet check valve has a much weaker spring which only has to exert the force necessary for a reliable closing. In this way, the medium is effectively prevented from being pushed back or sucked back into the feed line.

For the safety of the function of these system separators, it is necessary that a confusion during the installation of the check valves is excluded, otherwise a closing when the flow is reversed is no longer guaranteed. In the known system isolators, the insertion or screwing in of the check valves in the flow-through housing is therefore ensured in the functionally correct manner by receiving holes or threads of different sizes. This requires one different training at least the cages of the check valves. This is disadvantageous and also makes the valve more expensive, because the function of the check valves apart from the springs could consist of completely identical parts. If you consider the installation of the check valves in the flow housing, the use of the same cages for the check valves only prevents the safety aspect of the risk of confusion, since the installation of the first check valve at the location of the second check valve is possible with the same outer contour of the check valve cages. In this case, the function of the system separator is no longer available.

The object of the present invention is to provide a system separator in which check valves can be used on the inflow and outflow sides, which apart from the springs consist of completely identical parts, but cannot be used incorrectly.

This object is achieved in that the two spring-loaded check valves are composed of identical parts, but have different loading springs, and a sealing surface is provided both on the side of the seat collar and on the side of the guide part of the valve cage and that the flow housing is designed so that in each case only the inlet valve can be installed in the inlet and the outlet valve only in the outlet of the middle chamber. The invention ensures that various parts for the check valves are avoided, which leads to simplification of manufacture and storage. Furthermore, the processing of the flow housing is simple and inexpensive. According to an advantageous embodiment, at least the spring-loaded valve is arranged at an angle with respect to the center chamber. This eliminates the need to arrange a special stop in the system separator drain.

In a particularly advantageous embodiment, the two spring-loaded valves are arranged obliquely in the flow housing. This not only achieves favorable machining, but also considerably simplifies the installation of the check valves. The accessibility for processing and installing the check valves can also be improved by opening the middle chamber with a cover, the opening area of which is at least so large that the projection of the receiving surfaces for the check valves in the direction of the axis of the guide pins lies within the opening. The housing wall is designed as a stop without the flow through the flow housing being impaired thereby. Seeger rings are provided for fastening the valves in the flow housing, which results in both simple and inexpensive machining and also precise and tight positioning of the check valve in the flow housing. In order to also prevent the reverse installation of the check valves, a shoulder 144 and 144 'is provided between the seat collar 142 and 142' and the guide part 143 and 143 'of the cage, the diameter D _{k of which is} greater than the inner diameter D _{s of} the anti-seizure device 7 in the Installation is required compressed condition. This makes it impossible to fix the check valve when it is incorrectly installed.

Fig. 1 -

einen Systemtrenner mit geradem Durchfluß in Durchflußstellung,

Fig. 2 -

Schnitt AB aus Fig. 1,

Fig. 3 -

einen Systemtrenner mit Schrägsitzanordnung der Rückschlagventile in Sperrstellung,

Fig. 4 -

den Systemtrenner gemäß Fig. 3, jedoch in Durchflußstellung.

Fig. 5 -

eine Einzelheit V aus Fig. 4.

Further details and features of the invention will be explained with reference to the drawings. Show it:

Fig. 1 -

a system separator with a straight flow in the flow position,

Fig. 2 -

Section AB from Fig. 1,

Fig. 3 -

a system separator with angled seat arrangement of the check valves in the blocking position,

Fig. 4 -

3, but in the flow position.

Fig. 5 -

a detail V from FIG. 4.

1, the system separator has a straight passage from the inlet side 2 to the outlet side 3. The arrows shown in FIG. 1 indicate the direction of flow of the liquid medium. The flow housing 1 is installed in the pipe system via the inlet connection 2 and the outlet connection 3. The housing 1 also contains a central chamber 5, into which a relief valve 51 is installed, which is controlled by the diaphragm 14 via a valve rod 52. The inlet-side pressure is passed into the chamber 15 via a control channel 13 to act on the membrane 14. The flow housing 1 is closed with a cover 12.

A check valve, which consists of the valve plate 4, the cage 41 and the guide pin 46, is arranged in the middle chamber 5 both on the inlet side and on the outlet side. The check valve on the inlet side 2 corresponds in its individual parts exactly to the check valve on the outlet side 3, so that the cage 41 is exactly the same as the cage 41 ', just as the valve plate 4 corresponds to the valve plate 4' and the guide pin 46 to the guide pin 46 '. The check valves thus consist of completely identical parts, only the spring 44 on the inlet side 2 generates a stronger closing force than the spring 45 on the outlet side 103. The cage 41 consists of a seat collar 42 and a guide part 43 which fits into a corresponding recess in the housing wall of the flow housing 1 is used. The axial securing takes place by the seat collar 42 resting against the housing wall, while the radial fixing of the cage 41 takes place via the guide part 43 through the corresponding bore in the housing wall. However, this bore is continued by a through the flow cross section of the cage 41 annular shoulder 11 narrowed. The cage 41 has both on the side of the seat collar 42 and on the side of the guide member 43 a sealing surface, so that the seal of the valve plate 4bzw. 4 'can be sealed on both sides.

As already mentioned above, the check valve on the outlet side 2 consists of exactly the same parts as the check valve on the inlet side 3. However, on the outlet side 3 the sealing surface of the guide part 43 'cooperates with the valve plate 4', while on the inlet side 2 the Sealing surface of the seat collar 42 cooperates with the valve plate 4.

In order to prevent the check valve for the inlet side 2 from being installed on the outlet side 3, a stop 6 is arranged in the nozzle of the outlet 3 in an extension of the axis of the non-return valve and has a distance from the valve plate 4 'which is less than the sum of the opening stroke H of the valve plate 4 'and the block length B of the spring 44 or 45, which, however, is greater than the opening stroke H of the valve plate 4', measured from the valve plate 4 'when it is in its closed position. The block length B is understood to mean the length of the spring including its fastening collar on the guide pin 46 in the compressed state when the valve is opened.

As can be seen from FIG. 1, the check valve on the outflow side can be opened completely without the stop 6 impairing this opening stroke H. However, if the two check valves 4 and 4 'are interchanged and the check valve is used from the inlet side 2 to the outlet side 3, the guide pin 46 projects, the length of which is determined by the valve stroke H, the block length B and the length of the guide hub 47 of the cage 41 , outlet side so far into the drain opening that the guide pin 46 against the stop 6 bumps before the cage 41 can be inserted into the wall of the flow housing 1. It is therefore not possible to mount the check valve 4 for the inlet side 2 on the outlet side.

In order to prevent the check valve 4 'from the discharge side 3 from being installed on the inlet side, an annular shoulder 11 is provided in the inlet opening in the throughflow housing 1. This shoulder 11 does not extend axially over the entire bore 116 in the housing wall, but leaves a distance L1, measured from the cage seat, which is greater than the length L2 of the guide part 43, but less than the axial length L2 of the guide part 43 and the thickness L3 of the valve plate 4 or 4 '. In this way, the length L2 of the guide member 43 is easily accommodated when the valve 4 is inserted into the wall of the flow housing 1 on the inlet side 2. However, if the valve 4 'is mistakenly inserted from the outlet side 3 on the inlet side 2, the valve plate 4' abuts the shoulder 11 in the bore for the cage 41 without the cage 41 'having the correct seating position for axial fixation by the seat collar 42 'or for radial fixation by the guide part 43'.

3 and 4 describe another advantageous embodiment of the invention.

The flow-through housing 111 has an inlet connection 102 and an outlet connection 103. The check valves 104 and 104 ′ are arranged at an angle within the housing 111. They form an angle with respect to the central chamber 105. The check valves 104 and 104 'each consist of identical parts, namely a cage 141 or 141', which has a seat collar 142 or 142 'and a guide part 143 or 143'. The cage 141 and the cage 141 'have both on the side of the seat collar and on the side of the guide part sealing surfaces with which the valve plates 104 and 104 'work together. Since the check valves 104 and 104 'are identical in their individual parts, the check valve 104 on the inlet side 102 corresponds exactly to the check valve 104' on the outlet side 103, so that the cage 141 is exactly the same as the cage 141 ', as is the valve plate 104 corresponds to the valve plate 104 'and the guide pin 146 and the guide pin 146'. Only the spring 44 on the inlet side 102 has a stronger closing force than the spring 45 on the outlet side 102. The cage 141 is inserted into a corresponding recess in the housing wall of the flow-through housing 101. The axial securing is carried out by the seat collar 142, which is held in contact with the housing wall by a Seegersicherung 7, while the radial fixing of the cage 141 via the guide part 143 takes place through a corresponding bore in the housing wall. However, this bore is narrowed in continuation of the flow cross section of the cage 141 by a shoulder 111 in the housing wall.

In this embodiment too, the check valve on the outlet side 103 consists of exactly the same parts as the check valve on the inlet side 102. However, on the outlet side 103, the sealing surface of the guide part 143 'cooperates with the valve disk 4', while on the inlet side 102 the Sealing surface of the seat collar 142 cooperates with the valve plate 104.

The check valve for the inlet side 2 cannot be installed on the outlet side 3, since in an extension of the axis of the non-return valve the housing wall is guided with the outlet connection 103 in such a way that the distance between the housing wall and the valve plate 104 'only permits the valve stroke H, as shown in Fig 4 emerges. The guide pin 146 of the inflow-side check valve 104, however, requires a distance which is at least the block length B longer than the valve stroke H. Conversely, the check valve 104 'on the outlet side cannot be installed on the inlet side 102, because of the Shoulder 111 can only accommodate the length L2 of the guide member 143.

The check valves 104 and 104 'are particularly easy to use due to this inclined seat arrangement. In addition, the housing is more accessible for machining than in the embodiment according to FIG. 1. The middle chamber has an opening 117 which is so large that the projection of the receiving surfaces for the check valves 104 and 104 'in the direction of the axis of the guide pins 146 and 146 'still lies within the opening 117. As a result, the tools for machining the valve seats can be inserted in a straight line, which greatly simplifies machining. The check valves 104 and 104 'can also be exchanged simply and easily after opening the cover 112, which closes the opening 117.

Together with the cover 112, the membrane 114 and the relief valve 151 with its valve rod 152 are removed at the same time.

For the rest, the function in this embodiment is the same as already described in FIG. 1. As soon as a pressure difference to the central chamber 105 of greater than 0.14 bar arises on the inlet side 102, this pressure is passed via the control channel 113 and the control bore 116 into the chamber 115 to act on the membrane 114. As a result, the relief valve 151 is moved down onto its valve seat and the relief opening is closed. If the pressure rises further, the closing force of the spring 44 is overcome, the check valve 104 on the inlet side moves into the position shown in FIG. 4, so that the flow through the central chamber 105 can take place. The check valve 104 'with the much weaker spring 45 also opens so that the medium can flow out on the outflow side. If the pressure on the inflow side drops below the stated value of 0.14 bar, the check valve 104 closes and, since the membrane 114 is no longer acted upon, the relief valve 151 is also opened again by spring pressure. Both check valves 104 and 104 'are then in the closed position, as shown in FIG. 3.

Due to the angular arrangement of the check valve with respect to the central chamber, the valve axis is directed towards the housing wall, which thus forms a stop 61, so that the check valve on the inlet side cannot be installed on the outlet side. There is therefore no need for an additional stop 6 in the outlet connection 103, as shown for example in FIG. 1. However, the same can also be achieved with a straight flow, as shown in FIG. 1, if the drainage connection 3 of the housing 1 is arranged at an angle to the valve axis, so that the housing wall forms a stop 61 due to this bending.

With a parallel arrangement of the check valves, the incorrect installation of the check valves according to the invention can be prevented by the housing wall of the flow housing 1, 101 being guided in such a way that it forms a stop which is farther from the valve plate than the stroke height of the valve, but less than the lifting height H and the block length B are away from the valve plate.

As already described above with reference to the figures, a shoulder 11 or 111 is provided on the inlet side 2 or 102, which prevents the installation of the check valve on the outlet side.

Another problem can arise in that the two check valves are not only interchanged, but are installed in the opposite direction. For example, the cone 141 could be installed in such a way that the seat collar 142 assumes the seat provided in the housing 1, 101, but the guide part 143 points upward in the flow direction, so that the valve disk 104 is opposite to the direction of flow. If it were the inlet check valve, nothing would happen, but the device would not be functional. However, if the drain check valve with the weaker loading spring 45 is involved, this could lead to the inlet check valve opening unintentionally too early.

In order to prevent such installation in the wrong direction, a shoulder 144 or 144 'is provided, the diameter D _k of which is matched to the inside diameter D _{s of} the anti-seizure device such that the diameter D _{k of} the cage shoulder 144 is larger than the inside diameter D. _s the Seegersicherung, at least in the compressed state. In this way, the insertion of the Seegersicherung 7 in its groove 148 is prevented because the compressed Seegersicherung 7 can not be pushed over the shoulder 144. This means that the cage and thus the check valve in the housing 101 cannot be attached at all when the installation is reversed.

With the measures according to the invention, incorrect installation of the parts of the check valves, which in themselves look identical and are therefore easily confused, is prevented in a simple manner. The number of pieces is doubled due to the similar parts and thus more economical production is achieved. The openings provided in the housing 1, 101 for the installation of these check valves can also be of completely identical design.

Reference list

Flow housing

1; 101

Inlet / inlet connector

2; 102

Drain / drain nozzle

3; 103

Inlet valve plate

4; 104

Drain valve plate

4 '; 104 '

Middle chamber

5; 105

Cage

41; 41 '; 141; 141 '

Seat waistband

42; 42 '; 142; 142 '

Guide part

43; 43 '; 143; 143 '

shoulder

144; 144 '

Load spring

44; 45

shoulder

11; 111

attack

6; 61

Guide pin

46; 146

Guide hub

47; 147

Relief valve

51; 151

Valve stem

52; 152

chamber

15; 115

Shoulder distance

L 1

Lead length

L 2

Valve plate thickness

L 3

opening stroke

H

Spring block length

B

cover

12; 112

Control channel

13; 113

membrane

14; 114

Control bore

116

Housing opening

117

Maritime security

7

Diameter securing device

D _s

Cage shoulder diameter

D _k

Claims (11)

System separator with a feed and a discharge flow housing, in which a spring-loaded inlet valve and a spring-loaded drain valve and a middle chamber are arranged between the two valves, and the two spring-loaded valves each have a valve plate and a cage for radial fixing in the flow housing a guide part and a seat collar for axial fixation, characterized in that the two spring-loaded valves (4; 4 ';104;104') consist of identical parts (41, 42, 43, 46, 47; 41 ', 42', 43 ', 46', 47 '; 141, 142, 143, 146, 147; 141', 142 ', 143', 146 ', 147') are composed, but have different loading springs (44, 45), and both the side of the seat collar and the side of the guide part (43, 43 '; 143, 143) of the valve cage (41, 41'; 141, 141 ') are each provided with a sealing surface and that the flow housing (1; 101) is also formed in this way is that only the inlet valve (4; 104) can only be installed in the inlet (2; 102) and the outlet valve (4 ', 104') in the outlet (3; 103) of the middle chamber (5; 105). System separator according to claim 1, characterized in that the flow housing (1; 101) at the inlet (2; 102) in continuation of the flow opening of the valve cage (41; 141) has a shoulder (11; 111), the distance (L1) from the cage seat greater than the length (L2) of the guide part (43; 143), but less than the length (L2) of the guide part (43; 143), and thickness (L3) of the valve plate (4 ';104'), and that a stop ((3; 103) 6; 61) is provided in the direction of the valve plate axis at a distance from the valve plate (4 ';104') in the closed position which is smaller than the sum of the opening stroke (H) of the valve plate (4; 104) and block length (B) of the spring (44, 45), but larger than the opening stroke (H) of the valve plate, (4; 104). System separator according to one or more of claims 1 or 2, characterized in that the stop (6) is arranged in the center of the drain (3). System separator according to one or more of claims 1 to 3, characterized in that at least the spring-loaded valve (104 ') is arranged at an angle on the outlet (103) with respect to the central chamber (105). System separator according to claim 4, characterized in that the two spring-loaded valves (104, 104 ') are arranged obliquely in the flow housing (101). System separator according to claim 5, characterized in that the central chamber (105) has an opening (117) which can be closed by a cover (112), the area of which is at least so large that the projection of the receiving surfaces for the check valves (104; 104 ') in Direction of the axis of the guide pins (146; 146 ') lies within the opening (117). System separator according to one or more of claims 4 to 6, characterized in that the housing wall is designed as a stop (61). System separator according to one or more of claims 1 to 2, 4 to 7, characterized in that the outlet (3; 103) in the flow direction after the check valve (4 ';104') is guided at an angle to the valve axis such that the housing wall at a distance from the valve plate (4 ', 104') in the closed position, which is smaller than the sum of the opening stroke (H) of the valve plate (4; 104) and block length (B) of the spring (44, 45), but greater than is the opening stroke (H) of the valve disk (4; 104). System separator according to one or more of claims 1 to 8, characterized in that a seeding fuse (7) is provided in each case for fastening the valves (4, 4 '; 104, 104') in the flow-through housing (1; 101) System separator according to one or more of claims 1 to characterized in that both end faces of the cage (41, 41 '; 141, 141') are designed as a valve seat. System separator according to claims 9 or 10, characterized in that a shoulder (144, 144 ') is provided between the seat collar (142, 142') and the guide part (143, 143 ') of the cage (141, 141') Diameter D _{k is} greater than the inner diameter D _{s of} the Seegersicherung (7) in the compressed state required for installation.

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