GB1597330A - Dry sprinkler for use in a fire extinguishing system - Google Patents

Abstract

In order to avoid corrosion and deposits of lime and slurry in the interior of a dry sprinkler enclosed by a tubular casing (3), said sprinkler is provided with an axially displaceable pre-sealing member (27), at the water-supply-side end of which there is seated a sealing part (17) which, in the rest state of the sprinkler, blocks the water supply to the sprinkler nozzle (4), in the region of a sealing bore (23). The said sealing part (17) is seated at the rear end of a spacing rod (14) which is guided in the tubular casing (3) and the front end of which is pushed, in a spring-loaded manner, against a closure element (10) which is acted upon by the locking force of the sprinkler-triggering member and belongs to the sprinkler nozzle opening (13). If the sprinkler-triggering member (9), on heat-induced actuation, no longer exerts any locking force, the spacing rod (14), both under the pressure of an axially effective spring (25) and under the water pressure acting on the sealing part (17), pushes the closure element (10) away from the nozzle opening (13). In this arrangement, the sealing part (17) releases the sealing bore (23), with the result that the extinguishing water flows through the tubular casing (3) of the sprinkler and can reach the baffle plate (7) via the nozzle opening (13). <IMAGE>

Description

(54) DRY SPINKLER FOR USE IN A FIRE EXTINGUISHING SYSTEM (71) I, JOHANN GEORG MOHLER, a Swiss citizen of Laugneristrasse, CH-6352 Weggis, Switzerland, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a dry spinkler with a cover tube as dry chamber arranged between an extinguishing-water feed-line and a sprinkler nozzle, said cover tube being connectable with a connection piece which is mounted loosely on the feed-line side of the cover tube, and a pre-sealing member which can be brought from a stand-by position into an operating position and which is effective between the spinkler nozzle and the extinguishing-water feed-line.

Sprinkler nozzles are normally connected to a network of pipes which is under water-pressure in order to become effective immediately after activation of the sprinklerrelease element. The disadvantage lies in that there is a danger of corrosion or chalk or mud precipitation in the sealing areas of the sprinkler shutter due to lack of operation over many years or insufficient maintenance of the system so that misfunctioning can occur in an emergency. One tries to eliminate this disadvantage by using dry sprinklers, whereby the sprinkler is no longer connected directly to the extinguishing-water means but over a "dry" intermediate piece to the same.

It is the object of the present invention to form a dry sprinkler of the type described in the introduction which is constructed simply to avoid the disadvantages mentioned, which allows free or only slightly hindered water-flow in the case of operation and which causes hardly any delay in the functioning of the sprinkler.

The dry sprinkler according to the present invention is characterized by the features of the Main claim.

One embodiment of the subject of the invention is described hereafter on the basis of the drawings. They show: Figure 1: partly in longitudinal section and partly a side view of a dry sprinkler of the type mentioned in non-operative or stand-by position; the sprinkler element with its release member and seal-divider is only shown schematically; Figure 2: the dry sprinkler shown in the same way as in Figure 1 in the activated or operating position of the sprinkler; Figure 3: the control and pre-sealing member of the dry sprinkler shown in the embodiment of Figure 1 or Figure 2 in side view, including the cross-section view of the axial movement restricting part for the control and presealing member, and Figure 4: a cross section along the line IV - IV in Figure 3, whereby the upper half of the figure (when viewed from the right), the pre-sealing member, and the lower half of the figure (when viewed from the left) shows the control rod in plan view relative to the movement-restricting part.

The same parts are marked with the same reference numbers in all the figures.

In Figures 1 and 2, number 1 marks a branch sleeve in the extinguishing-water feed-line, to which the dry sprinkler, described in the following, is connected. The connection piece is marked 2 (the important inventive parts hereof will be described later), and 3 marks a cover tube, into the front or left-hand side end of which a sprinkler nozzle, generally marked 4, is screwed. This can. for example, be formed according to Swiss Patent No. 1,507,047 and comprises a nozzle body 5 with a screw thread 6, engaged with the cover tube 3. The sprinkler nozzle shown further comprises an impact-plate 7 which is joined to the nozzle body 5 by means of carrying bolts 8.A release member 9 is supported centrally on the inner side of impact-plate 7 and is further held on its opposite side in a sealing element generally marked 10, the shoulder 11 of which lies tight against a counter-shoulder 12 on the nozzle body 5, sealing the same. The sealing element 10 is furthermore centered in a nozzle opening 13 on the nozzle body 5 which forms the flow-out opening on the sprinkler nozzle 4.

Aligned on the longitudinal axis of the cover tube 3 is a distance rod genrally marked 14, the front end 15 of which faces the end of the sealing element 10 lying withm the nozzle body 5. Details of this distance rod can be seen in Figures 3 and 4. In the stand-by position of the dry sprinkler as shown in Figure 1, the end 15 of the distance rod 14 lies tight on said "inner" end of the sealing element 10.

The distance rod 14 comprises a number of centralizing pins 16.1 - 16.5 spaced out over the circumference of the rod which pass through the rod and are held fast in the same. Their function is described in detail in the following. At the back end, a sealing head 17 is arranged on the distance rod 14. The sealing head 17 is preferably pear-shaped and comprises, as best seen in Figure 3, a convex front section 18, a cylindrical seat part 19 adjacent to the section 18 and extending to a seat shoulder 19', with a sealing groove 20 to take up an O-ring seal 21, and a tapering, conical-bulbous run-out section 22.In the stand-by position of the dry sprinkler Figure 1), the seat part 19 is inside a seal-bore 23 on the "water-side" (back-)end of the connection piece 2, and its shoulder 19' lies, without actually having a function of restricting movement, opposite the shoulder 24 at the inner end of the seal bore 23. The seal head 15 can be, as shown, screwed onto the distance rod 14, and be of the same material as the rod, or be made of antoher material. It is also possible to have the seal head 15 integral with the rod.

A compression spring 25 is located within the cover tube 3 between the centralizing pin 16.3 and the front end 26 of the connection piece 2 and pushes the pre-sealing member generally marked 27 which comprises the distance rod 14 and the seal head 17 as main element, operatively into the stand-by position according to Figure 1, together with the water pressure exerted on the front section 18 on the seal head 17 against the sealing element 10 on the sprinkler nozzle 4. The space remaining between the inner wall of the cover tube 3 and the component parts described above can also be generally described as a dry chamber since it is normally, i.e. in the stand-by position of the dry sprinkler, free of water.

If by activation of the release member 9 of the sprinkler nozzle 4 the resistance against a movement of the distance rod 14 is removed, the pre-sealing member 27 moves under the influence of the above-mentioned forces into the position shown in Figure 2. Thereby, the seal head 17 leaves the seal bore 23, and the distance rod 14 moves a certain way to the left into the position according to Figure 2. It is centralized by the pins 16.1, 16.2 and 16.3 in respect of the inner wall of the cover tube 3 and by the centralizing pins 16.4, 16.5 in respect of the passage bore 28. The distance mentioned is equal to the way m (Figure 1 and 3) which the centralizing pin 16.1 can cover in diametrical U-shaped slits resp. grooves 29 in a guide shaft 30.The guide shaft 30 shown is in the inside of the cover tube 3, it can be adjusted therein and can move to the left to the stop on the nozzle body 5. The position of the guide shaft 30 in respect to the distance rod 14 is shown in Figure 3 for assistance, in the relationship according to Figure 1. It is understood that the guide shaft can also be fixed in the cover tube 3, e.g. screwed in.

When the pre-sealing member 27 moves to the left as mentioned, the front end 15 of the distance rod 14 enters into the nozzle opening 13 on the nozzle body 5. To insure a large enough (as necessary ring-shaped) extinguishing-water passage cross-section in the direction of arrows P and Q, the narrowest passages between the water-entrance point (bore 23) and in the connection piece 2 and the exit point on the front end of the nozzle bore 13 are chosen so that the necessary quantities of water can definitely pass through. For this puspose, it can be arranged that the distance rod 14 is tapered at its front end as shown by the graduation 31. Of course, other shapes for the rod end which are not described in more detail are also possible. A practical embodiment of a dry sprinkler according to the drawing resulted in the following sizes: Pressure P (bar) Flow amounts Q (liMin) 1 81.0 2 113 3 138.5 4 160 It is understood that the arrangement of the extinguishing-water feed-line can, with the described construction of the dry sprinkler, be above a blind ceiling. Since the length of the dry sprinkler can be practically any size depending on the chosen length of the cover tube 3 and also in respect of the distance rod 14 by given flow relationships (critical cross sections, pressure, amount of water,), it can be adapted within wide limits.For example, the length of the cover tube can be so regulated that its lower end protrudes beyond the blind ceiling by the thickness of a rosette (not shown) so that the parts of the nozzle body 5 protruding beyond the tube end can be practically level with the surface of the flange.

Since even with excellent sealing quality between the seal head 17 and the seal bore 23, some leakage water must be expected, a drainage hole 32 which also passes through the wall of the nozzle body 5, is located on the lower end of the tube cover 3, through which the leakage water can run out. The hole 32 ends, for this purpose at a point in the nozzle opening 13 which lies just in front of (or above) the sealing element 10 of the sprinkler nozzle 4.

WHAT I CLAIM IS: 1. A dry sprinkler with a cover tube as dry chamber arranged between an extinguishing-water feed-line and a sprinkler nozzle, this cover tube being connectable with the extinguishing-water feed-line over a connection piece loosely mounted on the feed-line side of the cover tube, and a pre-sealing member which is effective between the sprinkler nozzle and the extinugihsing water feed-line and which can be brought from a stand-by position into an operating position, wherein the presealing member consists mainly of a rod element being adjustable within axial limits in the inside of the cover tube and a sealing part connected to said rod element, that the sealing part has an axially adjustable cylindrical top surface part with a radially effective sealing means in a central axial bore of the connection piece, and that the rod element in the stand-by position of the dry sprinkler, exerts pressure on its end opposite the sealing part against a sealing element of the sprinkler nozzle and is pushed in an operating position so far in the flow-exit direction against the nozzle opening of the sprinkler nozzle that said cylindrical top surface part on the sealing part is pushed out of the axial bore in the connection piece in the direction of the extinguishing-water entrance.

2. Dry sprinkler according to claim 1, wherein a guide shaft in the cover tube has at least one groove to take up a stop member connected with the rod element for the purpose of restricting the axial movement of the pre-sealing member in the direction of the flow exit.

3. Dry sprinkler according to claim 2, wherein said stop member is a centralizing pin passing through the rod element, this pin being inserted in the groove or grooves and coming to lie in the operating position in the base of the U-shaped groove.

4. Dry sprinkler according to claim 1, wherein the rod element is kept at a distance by distancing means protruding from it, in respect of both the cover tube and the connection piece and is at the same time centralized in their longitudinal axis.

5. Dry sprinkler according to claim 4, wherein said distancing means are, for the purpose of achieving a centralizing effect, centralizing pins spaced out over the circumference of the rod element passing through and being anchored in the same, the ends of these pins being at a range of play from the inner wall of the cover tube or the connection piece.

6. Dry sprinkler according to claim 1, wherein said sealing means is an O-ring on the sealing part which is inserted into a groove located in the area around the cylindrical surface part, whereby the periphery of the O-ring lies against the seal bore on the connection piece in the stand-by position of the dry sprinkler.

7. Dry sprinkler according to claims 1 ot 6, wherein the sealing part is formed as a seal head which is placed detachably on the rod element.

8. Dry sprinkler according to claims 1 or 6, wherein the sealing part is integral with the rod element.

9. Dry sprinkler according to claims 1 ot 6, wherein the seal head is made of a different material to the rod element.

10. Dry sprinkler according to claim 1, wherein a drainage hole for the drainage of leakage water is arranged on the frong end of the cover tube, in the space immediately behind the sealing element of the sprinkler nozzle, passing through the wall of the tube cover and that of the nozzle body.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. described construction of the dry sprinkler, be above a blind ceiling. Since the length of the dry sprinkler can be practically any size depending on the chosen length of the cover tube 3 and also in respect of the distance rod 14 by given flow relationships (critical cross sections, pressure, amount of water,), it can be adapted within wide limits. For example, the length of the cover tube can be so regulated that its lower end protrudes beyond the blind ceiling by the thickness of a rosette (not shown) so that the parts of the nozzle body 5 protruding beyond the tube end can be practically level with the surface of the flange. Since even with excellent sealing quality between the seal head 17 and the seal bore 23, some leakage water must be expected, a drainage hole 32 which also passes through the wall of the nozzle body 5, is located on the lower end of the tube cover 3, through which the leakage water can run out. The hole 32 ends, for this purpose at a point in the nozzle opening 13 which lies just in front of (or above) the sealing element 10 of the sprinkler nozzle 4. WHAT I CLAIM IS:

1. A dry sprinkler with a cover tube as dry chamber arranged between an extinguishing-water feed-line and a sprinkler nozzle, this cover tube being connectable with the extinguishing-water feed-line over a connection piece loosely mounted on the feed-line side of the cover tube, and a pre-sealing member which is effective between the sprinkler nozzle and the extinugihsing water feed-line and which can be brought from a stand-by position into an operating position, wherein the presealing member consists mainly of a rod element being adjustable within axial limits in the inside of the cover tube and a sealing part connected to said rod element, that the sealing part has an axially adjustable cylindrical top surface part with a radially effective sealing means in a central axial bore of the connection piece, and that the rod element in the stand-by position of the dry sprinkler, exerts pressure on its end opposite the sealing part against a sealing element of the sprinkler nozzle and is pushed in an operating position so far in the flow-exit direction against the nozzle opening of the sprinkler nozzle that said cylindrical top surface part on the sealing part is pushed out of the axial bore in the connection piece in the direction of the extinguishing-water entrance.

2. Dry sprinkler according to claim 1, wherein a guide shaft in the cover tube has at least one groove to take up a stop member connected with the rod element for the purpose of restricting the axial movement of the pre-sealing member in the direction of the flow exit.

3. Dry sprinkler according to claim 2, wherein said stop member is a centralizing pin passing through the rod element, this pin being inserted in the groove or grooves and coming to lie in the operating position in the base of the U-shaped groove.

4. Dry sprinkler according to claim 1, wherein the rod element is kept at a distance by distancing means protruding from it, in respect of both the cover tube and the connection piece and is at the same time centralized in their longitudinal axis.

5. Dry sprinkler according to claim 4, wherein said distancing means are, for the purpose of achieving a centralizing effect, centralizing pins spaced out over the circumference of the rod element passing through and being anchored in the same, the ends of these pins being at a range of play from the inner wall of the cover tube or the connection piece.

6. Dry sprinkler according to claim 1, wherein said sealing means is an O-ring on the sealing part which is inserted into a groove located in the area around the cylindrical surface part, whereby the periphery of the O-ring lies against the seal bore on the connection piece in the stand-by position of the dry sprinkler.

7. Dry sprinkler according to claims 1 ot 6, wherein the sealing part is formed as a seal head which is placed detachably on the rod element.

8. Dry sprinkler according to claims 1 or 6, wherein the sealing part is integral with the rod element.

9. Dry sprinkler according to claims 1 ot 6, wherein the seal head is made of a different material to the rod element.

10. Dry sprinkler according to claim 1, wherein a drainage hole for the drainage of leakage water is arranged on the frong end of the cover tube, in the space immediately behind the sealing element of the sprinkler nozzle, passing through the wall of the tube cover and that of the nozzle body.