WO1983003653A1

WO1983003653A1 - A valve arrangement for district heating systems

Info

Publication number: WO1983003653A1
Application number: PCT/SE1983/000132
Authority: WO
Inventors: Ab Naf
Original assignee: BJÖRKLUND, Jan, Erik; STAKE, Sten, Göran
Priority date: 1982-04-20
Filing date: 1983-04-12
Publication date: 1983-10-27
Also published as: GB2138543B; SE8202454L; GB2138543A; GB8409182D0; FI841250A0; FI841250A; JPS59500577A; SE439054B

Abstract

A valve arrangement which is especially designed for district heatign systems and can be laid in the ground comprises a valve (1) which it should be possible to open and close by rotary movements. The bonnet (11) of the valve body and the valve stem (8) have connections (13, 15-17) which are located above the insulation (18), as is the stuffing box (14). The valve is combined with a bonnet extension (20) and a stem extension (21) which can be attached via the connections and which form a pressure-free upper part. The valve is thereby given a structural height such that it can be actuated and its position indicated at the plane (36) of the ground by means (22) at the upper end of the pressure-free part.

Description

A Valve Arrangement for District Heating Systems

The present invention relates to a valve arrangement for district heating systems and the like wherein pipelines with valves mounted in them .and surrounded by insulation are laid in the ground, and where it should be possible to manoeuvre the valves.from ground level between a closed and an open position by a rotary movement through a certain angle.

In such heating systems where valves, together with surrounding in- ^* εulation, are laid in the ground there has existed the hitherto un¬ solved problem of how to arrange devices which are required for manoeuvring the valves so that the insulation work on the valve, whic is carried out on site, can be effected irrespective of .and before the said valve devices are finally mounted, which often requires in¬ dividual adaptationof the overall structural height of the valve to the actual ground level.

Previously, there has been no alternative but to design district heating valves which are to be laid in the ground in one of the two following ways: A conventional valve with a standardised short struc tural height is mounted in the pipeline, while at the same time a specially adapted extension unit it fitted on the bonnet σf the valv body so that manoeuvre shall be able to be effected from the imagi¬ nary level in the future shaft above the valve. Only after this can the insulating material which is to surround the valve body and the lower part of the extension unit on. all -sides be applied. Adjustment the overall structural height of the valve at a later stage of the w ^' due to changed site conditions, for example, cannot be effected with out the insulation being opened up or a difficult operation being car ried out on the extension unit.

An alternative known arrangement is afforded in that a valve manu¬ facturer keeps valves available in an embodiment with an extended valve body bonnet. To the overall structural height this provides the customer has to adapt the level of the actuating devices rela¬ tive to the ground, and possibly also the depth of the district heating pipeline. If this adaptation is not possible due to the nature of the ground or other local conditions it is necessary to have the valve "tailor-made" in the factory, since it is obviously not feasible to modify the structural height of the valve after the pipeline with the valve has already been laid on the site. In this alternative again, therefore, the final preparation of the actual pipe line with its insulation is dependent on other work at the site.

Another disadvantage which is inherent in the first alternative moun¬ ting method is that the stem seals or stuffing boxes which are, of course, located at the top of the bonnet of the valve body and are cov red over during the insulation work, cannot be checked later during op tion unless the upper part of the insulation is removed. Since with th alternative mounting method a leaking stuffing box can cause irreparabl damage to the valve body, the poor inspection facility counts heavily ag this alternative. If the other embodiment of the valve is selected in¬ stead, where the spindle seal is located in the non-insulated part of the extra long bonnet of the valve body, problems arise for the valve manufacturer both of holding a stock of valve body parts or complete valves with a wide selection of structural heights so as to be able to meet the varying demands from the installation firms, and also of pro¬ viding the flexibility desired by the latter, allowing them to adapt a finished valve from stock without the risk of jeopardising the technic characteristics as verified by the manufacturer, when there is an un¬ foreseen change in the installation work.

It is the object of the present invention to set aside disadvantages o this kind, and to provide an improved valve arrangement for district heating systems which itself provides the flexibility required in the installation.

These objects are achieved with the present invention, which is charac terised by the combination of a valve body comprising a bonnet under

UREΛ _av_tpi over-pressure from the medium in the valve body and extending at an angle relative to the pipeline, pointing upwards when the valve is mounted therein, its upper end being widened out in a radial direc¬ tion to form an upwardly facing connecting element, the length of the bonnet being such that the connecting element is located above the insulation, a valve stem, which extends through the bonnet, in the wall of which there is means for mounting the stem rotatably and sealing it against the over-pressure in the bonnet, and which has a coupling en projecting upvards from the conneting element; a bonnet extension which is formed at its lower end to a downwa facing connecting element which fits against the connecting element of the bonnet and by means of which the bonnet extension can be fixe in a specific rotary position on the bonnet so that the valve body i provided with a part extending in a line with the bonnet and upward towards ground level, which part is non-rotatable and is not under over-pressure from the medium; a stem extension which is designed to be connected to the coupl end of the stem so that the stem extension extends upwards concentr cally with the stem, through the bonnet extension and out through th upper end thereof, where the stem extension is guided; means for restricting the rotation of the stem to the said angl and enas on the stem extension and the bonnet extension for ac ting the valve and indicating its position.

The invention will be explained in more detail below with reference t the accompanying drawing. Figure 1 shows, partly in section, the valv arrangement according to the invention after its installation in a district heating pipeline. Figure 2 is a longitudinal section which shows the structure of the valve in more detail. Figures 3 and 4 show the arrangement in a cross-section and in a view from above along the lines III-III and IV-IV, in Figure 2, respectively.

Ball valves are the type of shut-off valves which are most frequently used in district heating systems and the embodiment example shown on the drawing is therefore based on a valve of this type. ' However, this does not mean that the invention cannot also be applied to the closely-related butterfly valves or to other types of valves which, incorporated in pipelines, can be laid in the ground and can be adapted to being opened and closed from ground level by ro- tary movement through a specific angle.

The valve 1 which is shown in an embodiment for welding has a valve body 2 composed of a central casing part 3 with two end-pieces 4 inserted therein which each have a seating ring 5 mounted in their inner ends, while the outer ends are used in the welding of the valve into the pipe 6 appertaining to a district heating system. A spherical valve member 7 is disposed in a conventional manner so that it can rotate through 1/4 of a revolution towards and away from the open position shown in Figure 2, in order to control the flow through the pipeline, in conjunction with the valve seats 5. For this purpose, the valve member is connectedto a stem 8, the inner end of which is non-circular and is fitted in a corresponding cut-out in the valve member. The goindle is rotatably mounted by means of two concentric slee or guideways 10 disposed spaced apart in the direction of the axis of rotation 9 and forming part of a bonnet 11 extending perpendicular- ly upwards from the casing part 3. The upper end 12 of the bonnet is widened out in the radial direction to form an upwardly facing con¬ necting flange or a similar connecting element 13. The stem is sealed. here outwardly against the medium pressure in the bonnet of the valve body by means of a few O-rings 14 made of rubber or the like, which are held in place in a known way by support rings (not shown) which can be released from above if the sealing rings need to be changed.

The stem 8 extends seme way beyond the bonnet 11 , forming a coupling end 15 which is located above the connecting element 13 and is cylind¬ rical in the exemple; it may be equipped for actuation purposes with a coupling pin 16 which passes through the stem, or alternatively a keyway or so-called splines. A pin 17 is driven into the connecting element 13 from above to form a stop to restrict the actuation movement The valve described here may be mass-produced by the manufacturer and after assembly and operating tests it can be held in stock as a basic embodiment specially designed for district heating systems. This differs from valves for other purposes in that the bonnet 11 is longer, which is advantageous in view of the insulation of the valve. As Figure 1 shows the end 12 of the bonnet is actually loca¬ ted outside the insulating material which is applied round the valve body 2 and the pipe 6, in prefabricated halves or in^' tubular form, f example. Even if it should be desired to place supplementary insula- tion round the bonnet 11 of the valve body,the upwardly facing connec ting element 13 .and the coupling end 15 on the stem will be accessibl even after the insulation work, and it is also possible to check the functioning of the stuffing box or sealing rings 14 easily. A leak fr the inside of the valve past the stem 8 will not be hidden by the in- sulation and the risk for external corrosion damage to the material o the valve body is eliminated thereby.

In order to be able to manoeuvre and indicate the position of valves in the pipeline system from a point at ground level or in a shaft 19 dug down into the ground when the pipeline system has been covered wi earth after insulation, - this method of installation is now more usu than laying in culverts with special descent holes at the points wher the valves are positioned -the valve in the above-described basic embodiment is combined, according to the characteristic features of t invention, with a bonnet extension 20, a stem extension 21 which is r tatable therein, and means 22 at the top of the bonnet and stem exten sions for actuating and indicating.

As can most clearly be seen in Figure 2, the bonnet extension 21 com¬ prises a tubular part 23 which is formed at the bottom to a downwards facing connecting element 24 which fits against the connecting elemen 13 on the bonnet 11 and which consists in the embodiment example show of a counter-flange 24 welded onto the tubular part 23. The bonnet ex sion 21 can be fixed on the bonnet 11 by means of bolts 42 or other fixing devices on the said connecting element, in one distinct positi determined, for example, by guide pins 41, so that the extension is

OΛ-I given a specific rotational position relative to the valve body and its seats 5 while at the same time it is concentric with the axis of rotation 9 of the valve body bonnet.

The bonnet extension terminates at the top in a head part 25 which is firmly welded onto the tubular part 23 and bears a disc 26 for indicating the position and which belongs to the said means 22. For this purpose the disc may be provided with markings at specific angular locations, exemplified in the Figure by the letters"S" and "0" which give an indication of the position, shut or open respec- tively, in which the valve is located.

At least at its lower end, the stem extension 21 consists of a tube or sleeve 27 which can be threaded on the coupling end 15 of the ste with a good fit, and can then be fastened thereon with the pin 16 or some other rotary-movementtransmitting element. In addition, welded on at the lower end there is a plate 28 which has a recess of a cert depth in one quadrant, such that the fixed pin 17 which projects up from the flange 13 on the valve bonnet is accommodated in the recess when the valve stem 8 and the stem extension 21 are joined together, and at the same time, via the abutment surfaces 29 and 30 which are designed to be engaged in either direction by the pin, the recess li the rotary movement of the valve stem 8 and therefore defines the shu and open positions of the valve. Welded in at the upper end of the sleeve 27 there is a short shaft 31 which should be guided in the he part 25, preferably by a bush or ring 32 pressed into the latter, an which is terminated at the top by a hexagonal head 33. On the latter there is an indicator needle 34 with a non-circular hole which is adapted to the hexagonal head and which is held thereon by a circlip 35 or similar, so that the indicator needle follows the rotary movem when the stem extension 21 is rotated and consequently, together wit the fixed positionmarkings on the disc 26, shows how the valve is be manoeuvred.

Since it must of course be possible to determine the position of the valve after installation unequivocally, solely with the aid of the i cating means described above, when the arrangement is assembled it m be ensured that the indicator needle 34 moves from the "S" position into the "0" position when the valve is manoeuvred into its open position either directly via the hexagon on the spindle extension or by means of an actuator applied thereto, this end position being felt by the operator as the contact of the pin 17 against the surfac 29 (see Figures 4 and 3) .

It should be observed that the space in the bonnet extension 20 arou the stem extension 21 is not sealed outwardly by any sealing element in the gap around the shaft 31 , but the space should not be pressuri so that this gap, or a drainage hole provided for the purpose, will give "tell-tale" evidence during a subsequent inspection from above the stuffing box 14 is not leak-tight.

When the valve according to the present invention is being laid in t ground the further advantage relating to the installation process is obtained that the overall structural height can be adapted flexibly easily to the conditions which prevail at the working site. Due to t simplicity of the construction and the absence of stem sealing in th bonnet extension it is of course possible for the installation team carry out this adaptation themselves. For this they can select the length which the tubular part 23 and the sleeve 27 need to have so t after assembly with the connecting element 24, .the head part 25 and plate 28 (which will preferably be obtainable from the valve manufa turer) , and after the two extension parts are mounted on the bonnet 1 of the valve body and the valve stem 8 respectively, the actuation a indicating means 22 for the valve will come at the intended level re tive to the plane 36 of the ground. This work by the installation te can naturally be facilitated if the tubular part and the sleeve are factured and stocked in certain very frequently occurring module leng

After the valve has been assembled, before back-filling with earth or similar filling material 37 is carried out,protection should be fitte around the upper parts of the valve in the form of a plastic tube 38 extending upwards fran the insulation 18 as shown in Figure 1. Even i the shaft has a cement cover 39 it is preferable for the tube to be closed off with a protective cover 40 which screws onto it.

OA1PI

Claims

1. A valve arrangement for district heating systems and the like wherein pipelines with valves mounted in them and surrounded by insulation are laid in the ground, and where it should be pos¬ sible to manoeuvre the valves from ground level between a closed and an open position by a rotary movement through a certain angle, c h a r a c t e r i s e d by the combination of a valve body (2) comprising a bonnet (11) under over-pressure from the medium in the valve body and extending at an angle relative to the pipeline,^' ointing upwards when the valve (1) is mounted therein, its upper end (12) being widened out in a radial direc¬ tion to form an upwardly facing connecting element (13) , the length of the bonnet being such that the connecting element is lo¬ cated above the insulation (18); a valve stem (8) which extends through the bonnet, in the wall of which there is means (10, 14) for mounting the stem rotatably and sealing it against the over¬ pressure in the bonnet, and which has a coupling end (15) projec¬ ting upwards from the connecting element (13); a bonnet extension (20) which is formed at its lower end to a downwards facing connec ting element (24) which fits against the connecting element (13) of the bonnet and by means of which the bonnet extension can be fixed in a specific rotary position on the bonnet so that the valv body is provided with a part extending in a line with the bonnet a upwards towards ground level, which part is non-rotatable and is not under over-pressure from the medium; a stem extension (21) whi is designed to be connected to the coupling end (15) of the stem s that the stem extension extends upwards concentrically with the stem, through the neck extension (20) and out through the upper en (25) thereof, where the stem extension is guided; means (17, 28-30 for restricting the rotation of the stem to the said angle, and means (22) on the stem extension (21) and the bonnet extension (20 for actuating the valve and indicating its position.