DE7619292U1 - BELLOWS VALVE WITH HIGH LEAK RELIABILITY - Google Patents

Description

Bellows valve with a high level of security against damage

In some areas of application of valves there is an extremely unreliable sealing of the flowing medium against the Outside atmosphere. This is, for example, the Pall in chemical Systems in which hot oil is used as a heat transfer medium for heating under moderate excess pressure, in the Reactor technology and in other fields. For these applications, bellows valves are usually used in which the spindle or push rod moving the valve closing element is surrounded by a mostly metallic bellows, the one with its lower end at the öcnj-ieuexemeni bwIudÜ uüci ^. the push rod is sealingly connected and with his upper end tightly fastened in the valve housing 1st

In the event of a possible failure of the bellows or if the connection points of the bellows become leaky, another To have security against leakage of the flow medium is outside the bellows seal, i. H. in the direction of flow of any escaping medium behind the bellows seal a standard stuffing box seal is also arranged as a further seal »

The disadvantage of this training is that a stuffing box seal no completely secure seal guaranteed · This

Flat,

The disadvantage is serious if there is a risk of even the smallest amount of the flowing medium escaping comes, z. B. with the escape of hot oil to the risk of fire, with the escape of toxic media to the risk of poisoning or if radioactive substances are released, there is a risk of contamination. In these cases, extreme tightness and security requirements are made.

The present innovation has the task of creating a bellows valve while avoiding the disadvantages described, its sealing reliability that of the known valves is still essential exceeds. It should nevertheless remain reasonably inexpensive.

The starting point is a bellows valve with a push rod moving the valve closing element, at the lower one End the lower end of a bellows «is welded on-

is and with a further, external safety seal the push rod opposite the housing neck.

To solve the problem, it is proposed according to the innovation, that another outer bellows serves as a further safety seal, the lower end of which is welded tightly to the push rod and its upper end is welded tightly to the housing neck.

This series connection of two bellows seals ensures a correspondingly high level of security, since the fall

■ · 3 -

the simultaneous failure of two independently effective seals can be practically ruled out. Each of the two bellows seals is that of this type of seal has the well-known advantage of the almost absolute sealing effect.

In operation, only the inner of Paltenbälge under the action of the flowing medium, d _o h _o are under appropriate pressure and temperature loads is first. For this reason, it is sufficient and expedient if the outer bellows is designed for less stress, which means that it can be considerably cheaper. A bellows with a smaller number of waves is sufficient.

As a drive for the push rod that actuates the closing element a handwheel can be used in a manner known per se, which connected to the pushrod by means of a rotating tup fix xau, or a suitable servo drive, e.g. a hydraulic one or electric drive »

Around the outer end of the inner bellows in a simple way in the housing neck of the valve cover, e.g. by welding, to be able to fasten tightly, it is furthermore appropriate to if the housing neck is divided into two parts in this area, wherein After assembly, the housing halves are expedient are also welded together tightly. There is a strong connection between the housing halves with each other expediently by means of a screw connection bond made so that the weld seam only needs to serve as a seal.

It is also recommended that in the wall of the outer (xehousing neck half) a pressure and / or temperature sensitive Warning device is provided. Then if the inner bellows fails or one of its connection points leaks, the medium can flow out into the space monitored by the warning device, so that it responds and the operator is informed about the condition of the valve and a repair can be arranged

In fact, it is not the point of the proposed design to continue the valve after a failure of one of the bellows to be ranked, although the other bellows is still completely impervious to leakage of the medium the environment offers. The remaining seal would no longer be guaranteed with the necessary security.

Since if the valve is faultless, only the inner bellows is underneath the high load caused by pressure and temperature is also good the probability of its failure is slightly higher than that of failure of the outer bellows. That way you can In any case, a warning can be expected and there is no need to fear that initially, unrecognized, the outer bellows fails and then a failure of the inner bellows too, leading to a surprising escape of the medium If necessary, it can also be ensured in the computational design of the valve that a first Failure of the inner fattening bellows is to be expected »

To ensure complete security against this case, which in itself can no longer be assumed with a practical probability

»« • I I

r ../; i

.1 I

<■ ι i

do.

to offer may be outside the outer bellows yet another seal, e.g. B. a conventional gland packing are provided.

The innovation is illustrated below by the description of a Embodiment further explained with reference to the accompanying drawing. This shows the sectional representation of a valve according to the invention with "tandem" -]? old bellows.

A valve cover is attached to the housing 1 by means of stud bolts, to which fastening a seal by a sealing weld 4 is added. From the valve cover protrudes also welded on the housing neck, which consists of the two halves 11 and 12. The inner housing half 11 is with the outer housing neck half 12 in terms of strength by stealing one into the other and in terms of leakage by means of a Sealing weld 15 connected.

The closing element 5 of the valve is actuated by a push rod 6, at the upper end of which is a drive for reciprocating Shift attacks. This drive consists of a spindle 24 carrying the handwheel 23 via a rotary coupling 22 is rotatably and axially immovably connected to the push rod 6. The plate of the rotary joint 22 is means lateral indentations non-rotatably "guided by lateral stud bolts 21. Since the push rod 6 is rigidly connected to this rotary coupling plate β, it is thus also against rotation secured. When the spindle 24 is rotated, it moves in that of the stud bolts 21 by means of its thread held threaded plate up and down and thus generates the valve actuation movement

m '-' K Vl J * v>. ι

At the lower end of the push rod 6, a connecting piece 7 is welded in the vicinity of the closing element 5 which in turn a first bellows 8 is attached by means of a weld 9, which because of its greater proximity to the flowing medium inner bellows should be called. The inner connecting piece 7 of the inner bellows 8 slides in a neck-like extension of the inner housing neck half 1t ο

The other end of the bellows 8 is connected to an outer connecting piece 10 connected by means of weld 13, this Connector itself on the band of the inner housing neck half 11 is attached by means of weld seam 14.

At a sufficient distance in terms of the operational actuation stroke of the push rod is above the outer one Connector 10 of the inner bellows a further connector is welded to the push rod by means of weld seam 18, which as the inner connector 17 of the outer Falteribalgs 16 is used here by means of a weld 19 is the attached outer bellows 16, the outer end of which is fixed to the outer connection piece 20, which in turn on the upper edge of the outer Grehäusehalshalshhalf 12 welded is.

In the outer connection piece 20 of the outer bellows there is no a scraper ring 26 encompassing the push rod 6 is inserted, which prevents the ingress of dust and the like *

tm'IM »

In the wall of the outer neck half 12 is a warning Device 25 installed, which emits an optical or acoustic signal in particular when an internal pressure occurs.

When the valve is in operation, the flowing medium can only reach into the space between the inner bellows 8 and the inner housing. neck half 11 penetrate, which space r ^ .ch outside on all sides is sealed by welding seams »

If the inner bellows or one of the associated sealing welds fail, the medium can continue through the gap between the push rod 6 and the outer connector 10 of the inner bellows and between the inner connector 17 of the outer bellows 16 and the inner wall the outer housing neck half 12 in that of the warning device 25 outflow from monitored space «. Here it is again against prevented from escaping into the atmosphere through the outer bellows and its sealing welds.

The warning device 25 responds and indicates that a Repair has become necessary "

, 'UWE J &. ·

Claims (1)

PROTECTIVE APPLICATION) OHE 1. Bellows valve with a valve closing element loading, wegenden push rod, at the lower end of which the lower end of a bellows is welded, the upper one The end opposite the housing neck is welded tight and with a further, external safety seal the push rod opposite the housing neck, characterized in that a further outer bellows (16) serves as a further safety seal, the with its lower end sealed against the push rod (6) and whose upper end is welded tightly opposite the housing neck (12). 2. Bellows valve according to claim 1, characterized in that dsr outer bellows (16) for designed to be less stressed. 3. Bellows valve according to claims 1 and 2, characterized in that the push rod (6) is driven by means of a handwheel (23) with which it over a rotary coupling (22) is connected. If »ι 4. Bellows valve according to claims 1 and 2 _t characterized in that the push rod (6) means a servo drive can be operated. 5 bellows valve according to one of the preceding claims, characterized in that the housing neck (11, 12) is in the area of the outer connecting piece (10) of the inner bellows (8) is divided 6. Bellows valve according to claim 5 » \ V characterized in that the two G-housing neck halves (11, 12) together by a screw connection and Sealing weld are connected. 7. bellows valve according to one of the preceding claims, characterized in that in the wall of the outer housing neck half (12) a pressure and / or temperature an appropriate warning device (25) is provided 8. Bellows valve according to one of the preceding claims, characterized in that the bellows are made of metal are made " S Ml • Ü 9β bellows valve according to one of the preceding claims, characterized in that at least one seal of the push rod (6) with respect to the housing is provided outside the outer bellows (16) 10. Bellows valve according to claim 9 _t characterized in that the outermost seal is a stuffing box.