DE8703291U1 - Pressure reducer - Google Patents

Description

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Munich, the
DruVa-Armaturen GmbH ₈

AD: Pat/GM 209/ -87E

PRESSURE REDUCER

The invention relates to a pressure reducer for gases of the highest purity, with a spring-loaded low-pressure membrane which, together with a housing base body, defines a low-pressure chamber, with a valve seat arranged in the housing base body and * 0 having a movable valve body, through which

Low-pressure membrane controlled valve, whose inlet is connected to a high-pressure supply line and whose outlet is connected to the low-pressure chamber. Pressure reducers of this type are also known as

"Bolt pressure reducer".
25

A pressure reducer of this type is known from the documents of the German utility model 85 30 949. In this known pressure reducer, a central hole is provided in the housing base, which is used for

Serves to accommodate the valve (regulator insert).
30

In the pressure reducer of the type mentioned above, the connection pieces are made in one piece with the housing base, so that there are no gaps or cracks where foreign bodies such as particles can build up, which break off after a long period of operation and get into the fluid flow. The one-piece design of the connection pieces with the housing base did indeed result in a considerable improvement, but the

Note: DruVa-Armaturen GmbH - 4 -

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Separation of aerosols or dust particles cannot be completely avoided, especially during very long periods of operation.

The invention is therefore based on the object of creating a pressure reducer of the type mentioned at the outset, in which particle contamination of the gas is prevented in an even more reliable manner.

This task is solved by the fact that the valve seat is formed in one piece with the housing base body.

The measure according to the invention minimizes the dead volume in the gas space and the number of movable and moving parts. In the pressure reducer according to the invention, there are no gaps or cracks between the valve seat for the control element and the housing base, so that it is guaranteed that the gas can be passed through the pressure reducer without gaps and dead spaces.

According to an advantageous embodiment of the invention, it is provided that the housing base has a closable bore for the introduction of the valve body.

It is particularly advantageous if the hole is provided on the side of the housing body facing away from the low-pressure membrane and runs perpendicular to the surface of the low-pressure membrane. In this case, the hole goes directly into the receiving space for the valve body. This solution is therefore particularly advantageous in terms of manufacturing technology.

According to a further advantageous embodiment of the invention, the bore is closed by a plug which has a spring seat on its end facing the bottom of the bore. Such a plug can simultaneously serve as a support for a return spring acting on the valve body.

According to a further advantageous embodiment, it is provided that the plug has an annular sealing bead on its end face facing the bottom of the bore. This sealing bead can be

Note: DruVa-Armaturen GmbH - 5 -

cc: Pat 209/7-87E

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Plugs must be made in one piece.

A further advantageous embodiment of the invention provides that the bore has a stop surface on which a sealing bead formed in one piece with the housing base body is provided. The sealing bead of the plug can strike this sealing bead directly in order to create a connection that is tight for the high-pressure gas and is free of gaps and cracks.
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However, according to a particularly advantageous embodiment of the invention, an elastic high-pressure membrane is arranged between the sealing bead of the plug and the sealing bead acting as a counter seal on the stop of the bore. The high-pressure membrane closes the receiving space for the valve body on the high-pressure side. It is operatively connected to the valve body and presses it towards the valve seat, i.e. in the closing direction of the valve.

According to a further advantageous embodiment of the invention, the effect of the membrane can be reinforced by a compression spring acting as a return spring arranged between the membrane and the front side of the plug. This embodiment has the advantage that the return spring acting on the valve body can be arranged outside the clean gas chamber, so that the clean gas chamber only contains the valve body as a movable part.

According to a particularly advantageous embodiment of the invention, it is provided that the plug is fastened in the bore by means of a screw flange. The use of the screw flange ensures that the plug is pressed evenly in the axial direction until the sealing beads provided are pressed against the membrane from above and below to create a tight connection.

According to a particularly inventive development of the inventive concept, it is provided that the housing base body has a one-piece metallic sealing bead against which the low-pressure membrane is pressed by means of a flange connection. According to the state of the art

Note: DruVa-Armaturen GmbH _ 6 -

cc: Pat 209/7-87E

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The tight connection between the housing base and the low-pressure membrane was created by providing an annular groove with an O-ring on the contact surface of the low-pressure membrane. It was surprisingly found that this type of connection also caused the risk of particle contamination and gas diffusion.

By providing, according to the invention, the metallic sealing bead formed in one piece with the housing base body, which is pressed flat when the flange connection is tightened, i.e. when the attachment flange of the housing upper part is pressed on, a gas-tight, gap-free and joint-free connection is produced which does not represent a collection point for aerosols or dust particles even after a long period of operation.

The invention is explained in more detail below using a preferred embodiment shown schematically in Figures 1 and 2. It shows:

Fig. i: an axial section through the pressure reducer

according to the invention;

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Fig. 2: a section along the section line II—II

the figure &igr; in slightly reduced
Scale.

The pressure reducer shown in Figure 1 has a housing base 2, which essentially consists of a solid stainless steel block that is hexagonal in plan view. A central recess i6 is provided in this, which serves to accommodate a regulator valve. A high-pressure supply line 6 in the form of a radial channel extends perpendicular to the longitudinal axis of the central recess i6 and opens into its outer surface. The recess i6 has a shoulder designed as a valve seat 4. The central opening in the valve seat 4 leads into a low-pressure chamber 3, which has the shape of a flat can. An axially parallel, eccentrically arranged channel 17 opens into this low-pressure chamber 3, which is connected to another radial channel 18. The radial channels 6 and 18 merge outwards into connecting pieces 19 and 20. The connecting pieces are produced by

Note: DruVa-Armaturen GmbH - 7 -

cc: Pat 209/7-87E

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A blank of the appropriate size was removed by machining around the connecting pieces and the connecting pieces remained as they were. The connecting pieces 19 and 20 are thus in one piece with the housing base body 2 and each have an external thread 21 and 22 ¹ respectively. The external thread is also in one piece with the connecting pieces and the housing base body. It is used to accommodate a union nut (not shown).

A valve body 5 (also called a control cone) is inserted _into the recess 16. The valve body 5 has a pin-shaped end section 21 which projects loosely through the opening in the valve seat 4. The pin-shaped end section 21 is followed by a truncated cone-shaped transition piece which can produce a tight seal with a correspondingly designed surface of the valve seat 4. A further section of the valve body 5, which is square in cross section, serves to guide the same in the central recess δ. The central recess 16 which accommodates the valve body 5 is closed off at its end facing away from the valve seat 4 by a (high-pressure) membrane 13. The membrane 13 rests on the base of a bore 7 which is coaxial with the recess 16 but has a larger diameter. The membrane 13 is pressed against the base of the bore 7, which acts as a stop 11, by a sealing plug 8. The sealing plug 8 is held in the bore 7 by means of a screw flange 14, which

?b is supported on a shoulder 8 ¹ of the plug 8 and presses the plug 8 towards the bottom of the bore 7. The screw flange 14 has an external thread which engages in a corresponding internal thread of the bore 7.

To create a high-pressure-tight, gap-free connection between the membrane 13 and the base of the bore 7, which acts as a stop, an annular metallic sealing bead 12 is provided at the base of the bore 7, against which the membrane 13 is pressed when the screw flange 14 is screwed in. An annular bead 10 corresponding to the annular bead 12 is provided on the front side of the plug 8.

The housing base 2 is attached to the side of the low pressure chamber 3 with

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cc: Pat 209/7-87E

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an elastic (low-pressure) membrane i. A metal sealing bead 15 integrally connected to the housing base body 2 is used to create a tight connection. The elastic low-pressure membrane 1 is pressed onto the housing base body 2 by a housing cover 22. The pressing between the housing cover 22 and the housing base body 2 is carried out by means of axially running screws, which, however, cannot be seen in the sectional view selected in Figure 1. The pressing causes the sealing bead 15 to be pressed by means of the low-pressure membrane 1, so that a tight, gap- and joint-free connection is created there.

The shape of the housing cover 22 is adapted to the shape of the housing base body 2. In particular, on its side facing the housing base body 2, it has a cylindrical recess 23, the diameter of which corresponds approximately to the diameter of the low-pressure chamber 3, such that the low-pressure membrane 1 runs approximately through the middle of the flat cylindrical chamber, which is formed from the low-pressure chamber 3 and the cylindrical recess 23 in the housing cover 22.

On the side of the low-pressure membrane &igr; facing the housing cover 22, a pressure plate 24 is arranged which serves as a seat for a compression spring 25. The compression spring 25 is guided in a tubular section 26 of the housing cover 22. The second seat 27 of the compression spring 25 is designed to be axially displaceable. For this purpose, a central bore with an internal thread is provided in the center of the end plate 26 ¹ closing the tubular section. A spindle 28 projects through this bore and is supported by a ball on the second spring seat 27. The spindle 28 can be rotated using a handwheel 29. Two stop nuts 30 and 31 serve to limit the axial displacement path of the threaded spindle 28.

The pressure reducer works as follows:

High-pressure gas flows through the radial channel 6 into the central recess 16, which contains the valve body 5. The force of the compression spring 25 pushes the low-pressure membrane 1 towards the valve body 5 and rests on its pin-shaped end section 21. Here-

Note: DruVa-Armaturen GmbH - 9 -

cc: Pat 209/7-87E

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by the valve body 5 is removed from the valve seat 4 and frees up an annular gap. The gas flowing into the central recess 16 flows through this annular gap into the low-pressure chamber 3. Depending on the amount of gas that is discharged via the eccentric axial channel 17 and the radial channel 18, a pressure builds up in the low-pressure chamber 3 formed by the low-pressure membrane 1 and the housing base body, which pushes the low-pressure membrane 1 away from the valve seat 4 against the effect of the pressure spring 25. As a result, the valve body is pressed towards the valve seat 4 by the effect of the return spring 32 and the annular gap between the valve body 5 designed as a control cone and the valve seat 4 is reduced or closed. In this way, the gas supply to the low-pressure chamber 3 is reduced. A constant pressure is thus established in the low-pressure chamber, which, within a certain range, is independent of the amount of gas removed via the connection piece 20. The magnitude of the pressure is instead only dependent on the ratio of the opposing forces acting on the membrane.

By turning the handwheel 29 to the right, the spindle 28 is screwed into the housing cover 22, whereby the spring seat 27 is moved in the direction of the membrane 1, so that the spring force acting on the membrane 1 increases. This means that in order to achieve the equilibrium of forces, an increased pressure must also prevail in the low-pressure chamber 3. As long as this increased pressure is not reached there, the force of the spring 25 pushes the membrane in the direction of the valve 4, 5, which acts as a nozzle, and opens the valve, so that high-pressure gas can continue to flow until the equilibrium of forces is reached and the valve is closed so that the amount flowing in is equal to the amount drawn off, thus establishing a constant pressure.

The housing base body 2 is shown in Figure 2 in a top view. As can be seen from Figure 2, it consists of a hexagonal solid block. Figure 2 also shows the central recess 16. Also visible in Figure 2 is the high-pressure line 6 designed as a radial channel.

Air: DruVa-Armaturen GmbH - 10 -

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which opens into the side wall of the central recess 16. Offset by 60 to the radial channel acting as a high-pressure line 6, a radial channel 6a with the same effect is provided in such a way that the two channels ° run in a star shape towards the center of the housing base body. In the

The eccentrically arranged axial channel 17 already explained in Figure 1 as well as a channel 17a with the same effect and offset by 60° to this channel open into the low-pressure chamber 3. The channel 17 is connected to the radial channel 18, as already explained.

¹ ^ has been explained with reference to Figure 1. In the same way, the

Axial channel 17a is connected to the radial channel 18a. Six longitudinal bores 33 in the housing base body 1 serve to accommodate screws for fastening the housing cover 22 (Figure 1). On four of the six side surfaces of the housing base body, channels 6, 18,

¹ ^ 6a, 18a aligned connecting pieces 19, 20, 19a, 20a are formed. These are produced by removing material from a blank of the appropriate size around the connecting pieces by machining, so that the connecting pieces remain. The connecting pieces each have an external thread 21 ¹ , 22', 21a and 22a, which is also turned in one piece. A metal seal in the form of an integrally formed annular bead 34, 34a, 35, 35a is provided on the front side of each connecting piece. With the aid of a union nut (not shown), a connecting pipe piece (not shown) which has a pressure shoulder can be pressed firmly against the front side of each connecting piece. Depending on the intended use, a sealing disc can be provided between the front of each connection support and the front of a connection pipe. Such a seal is preferably made of silver-plated stainless steel or electropolished. Such a connection can be made completely free of dead spaces and gaps, so that the accumulation of the finest particles is reliably prevented. In pursuit of the same goal, the entire housing base is electropolished inside and out.

Note: DruVa-Armaturen GmbH - 11 -

cc: Pat 109/7-87E

Claims (10)

• · ■ ■ DruVa-Armaturen GmbH Munich, current date: Pat/GM 209/7-87E 04.03.87 -PA 1. Pressure reducer for gases of the highest purity with a spring-loaded low-pressure diaphragm (1) which, together with a housing base body (2), delimits a low-pressure chamber (3), with a valve (4, 5) arranged in the housing base body (2), having a valve seat (4) and a movable valve body (5), which can be controlled by the low-pressure diaphragm (1), the inlet of which is connected to a high-pressure supply line (6) and the outlet of which is connected to the low-pressure chamber (3), characterized in that the valve seat (4) is formed integrally with the housing base body (2). 2. Pressure reducer according to claim 1, characterized in that the housing base body (2) has a closable bore (7) for the introduction of the valve body (5). 3. Pressure reducer according to claim 2, characterized in that the bore (7) is provided on the side of the housing base body (2) facing away from the low-pressure membrane (1) and runs perpendicular to the surface of the low-pressure membrane (1). 4. Pressure reducer according to claim 2 or 3, characterized in that the bore (7) is closed by a plug (8) which has a spring seat (9) on its end face facing the bottom of the bore (7). 5. Pressure reducer according to claim 4, characterized in that the plug (8) on its side facing the bottom of the bore (7) Note: DruVä-Armaturen GmbH - 2 - u.Z.i Pat 209/7-87E it ft ■ # · m - 2 - 1 front side has an annular sealing bead (io). 6· Pressure reducer according to one of claims 2 to 5, characterized characterized in that the bore (7) has a stop (11) on which a sealing bead (12) formed in one piece with the housing base body (2) is provided. 7. Pressure reducer according to claim 6, characterized in that an elastic high-pressure membrane (13) rests on the stop (11). 8. Pressure reducer according to claim 7, characterized in that a return spring (32) is arranged between the elastic high-pressure membrane (13) and the front side of the plug (8). 9· Pressure reducer according to one of claims 4, 5, 7 or 8, characterized in that the plug (8) is fastened in the bore (7) by means of a screw flange (14). 10. Pressure reducer, in particular according to one of claims 1 to q, characterized in that a one-piece metallic sealing bead (15) is formed on the housing base body (2), against which the low-pressure membrane (1) is pressed by means of a flange connection. Note: DruVa-Armaturen GmbH - 3 - AD: Pat 209/7 -87E