GB2420413A

GB2420413A - Bend indicator

Info

Publication number: GB2420413A
Application number: GB0425631A
Authority: GB
Inventors: Alan Stimpson; Peter Riley; Michael Worrall; Daniel Gill
Original assignee: IFI Ltd
Current assignee: IFI Ltd
Priority date: 2004-11-22
Filing date: 2004-11-22
Publication date: 2006-05-24
Anticipated expiration: 2024-11-22
Also published as: GB2420413B8; GB2420413B; GB0425631D0

Abstract

A bend indicator for indicating conformity with a minimum curve radius of a bend in a flexible hose comprises a base plate (20) having a first concave side (21) whose radius of curvature corresponds to the desired minimum curve radius, and a second, opposed, convex side (22), spaced apart from the first side, first constraint means (23) upstanding from the base plate along the first side thereof defining a concave curved surface against which a curved hose may rest in use, and second constraint means (24) upstanding from the base plate at at least the central part of the second side to engage a curved hose on the outer side thereof, and fastening means (25-28) to retain a hose against the base plate between the first and second constraint means, in use.

Description

BEND INDICATOR

Field of the Invention

This invention relates to a bend indicator for use in providing a ready visual indica- tion that a bend in a flexible hose connection conforms with minimum curve radius re- quirements. The indicator is particularly applicable to use with flexible connector hoses in fire sprinkler systems, although it is not limited to use with such systems.

Background to the Invention

The use of automatic fire sprinklers for protecting life and property from fire is well-known, and has been established for over 100 years. Where sprinklers are mounted in suspended ceilings, especially those with rectangular tiles, the positioning of the sprin- kler must not only be correct for effective coverage of the water spray, but also appro- priate visually, which generally means positioning at the centre of a tile. To achieve the correct position, the sprinkler has traditionally been connected to the range pipe or branch line of the pipe array supplying the water to the sprinkler by an "armover con- structed by trial and error from rigid pipe and fittings. This method is very time- consuming, involving the measurement on site of the component pipe lengths, and cutting and threading of the pipe before assembly. Accurate measurement in the confined space above a suspended ceiling is difficult, and in practice it has been found that errors fre- quently occur, resulting in the scrapping of components and additional work making and fitting new pipe lengths. In addition, after the installation is complete, small changes in ceil- ing height may occur, either through settlement of suspension means or to accommodate refurbishment, requiring adjustment. With rigid pipe work, this can only be done by re- To overcome these difficulties, corrugated stainless steel flexible hose connections have been adopted. These can be bent and formed by hand to the correct position, the outlet for the sprinkler then being clamped to the grid rails of the suspended ceiling. This method is much quicker and saves installation time, waste materials and mess, which in turn reduce costs and allow the building to be completed more quickly during the final stages.

The problem with using flexible hoses is that, for correct function, a minimum bend radius must be observed. If a bend is too acute, there can be an excessive water pressure drop in the flexible hose, reducing water flow and therefore the fire-suppressing efficiency of the sprinkler. In addition, excessive bending of the flexible hose could weaken it, reducing its safe working pressure. Accidental failure of a hose, with resultant water damage to the room and its contents below, could prove costly.

Unfortunately, although each flexible hose unit is supplied with attached warning labels about a minimum curve radius, together with full installation instructions and a curve gauge, and although the installers receive appropriate training, these flexible hoses have occasionally been installed with an excessively small bend radius, with the result that they are rejected on inspection, and have to be replaced.

In addition, there is the possibility that other trades working in the ceiling void many bend the flexible hose in an unacceptable manner, either unintentionally or to gain access to other work, not realising that they have affected the function of the sprinkler 1 5 system. During inspection of the sprinkler system, it is too time- consuming for the inspec- tor to climb to the ceiling void and use the minimum radius gauge to check that every bend in every flexible connection conforms to the minimum bend radius.

Summary of the Invention

Accordingly, the invention provides a bend indicator for indicating conformity with a minimum curve radius of a bend in a flexible hose, comprising a base plate having a first concave side whose radius of curvature corresponds to the desired minimum curve ra- dius, and a second, opposed, convex side, spaced apart from the first side, first constraint means upstanding from the base plate along the first side thereof defining a concave curved surface against which a curved hose may rest in use, and second constraint means upstanding from the base plate at at least the central part of the second side to engage a curved hose on the outer side thereof, and fastening means to retain a hose against the base plate between the first and second constraint means, in use.

The first constraint means may comprise a single curved wall upstanding from the base plate along the first side thereof. Alternatively, the first constraint means may com- prise a plurality of members upstanding from the base plate spaced apart along the first edge thereof.

The fastening means may hingedly extend from the first constraint means and are lockably engageable with the second constraint means, or from the second constraint means to be lockably engageable with the first constraint means. Latching means may be provided to secure the fastening means to the respective constraint means.

Preferably, at least the base plate and first and second constraint means are inte- grally formed as a plastics moulding. The fastening means may also be integrally moulded.

The indicator is preferably moulded in a bright coloured plastics material so as to be read- ily visible from the ground with normal ceiling heights.

The indicator of the invention is conveniently attached to any bend on a flexible hose which is more than 45 from the straight. It will demonstrate instantly both to the installer and to an inspector that the flexible connector has not been bent tighter than the specified minimum radius.

1 5 The indicator is simple to attach and to secure and provides a convenient bending guide for the installer.

Brief Description of the Drawings

In the drawings, which illustrate an exemplary embodiment of the invention and the type of flexible connection to which it can be attached: Figure 1 illustrates a typical flexible connection between a sprinkler system supply hose and a sprinkler installed in a ceiling tile; Figure 2 shows in plan and in cross-section a bend indicator according to the in- vention; Figure 3 illustrates how the bend indicator of Figure 2 can be used with 45 and 90 bends; and Figure 4 is a plan view illustrating the use of two bend indicators together for bends between 135 and 180 .

Detailed Description of the Illustrated Embodiment

Figure 1 shows an example of a known configuration using a flexible hose. The supply pipe 1 is provided with a T-connection 2 to which is coupled a corrugated stainless steel flexible hose 4 via a nipple 3. The hose 4 (typically referred to in the art as a "flexi- ble") is to be connected to a sprinkler head 6 via a reducer 5 which is mounted so as to extend through a ceiling tile 7 by means of a bracket 8, a support bar 9 and a mounting bracket 1 0 attached to the ceiling tile support rails 11. In order to make the connection between the hose or flexible 4 and the sprinkler head 6, the flexible has to be shaped into a curve and is flexible enough to permit this to be done by hand in situ. For typical instal- lations, a minimum radius of 75 millimetres is specified for any curve in the hose. While a simple gauge is provided to indicate the minimum radius, it is not possible to judge the accuracy of the bend remotely when the installation is inspected.

Figure 2 illustrates a bend indicator according to the invention. It comprises a base plate 20 which is substantially planar and which has a concave edge 21 whose radius of curvature corresponds to the desired minimum radius for the bend, and an opposed convex edge 22 of essentially the same curvature, spaced from the concave edge 21 by a distance equal to the maximum diameter of the hose to which it is to be attached. A 1 5 curved wall 23 extends normally to the base plate 20 along the concave edge 21 over the full length thereof. A second curved wall 24 extends normally to the base plate 20 along a central part of the convex edge 22. A pair of fastening arms 25 are integrally moulded with the waIl 24 in such a manner as to provide a reduced thickness hinge portion 26 which allows the arm 25 to be hinged over the open channel between the walls 23 and 24. At the free end of each arm 25 is provided a simple detent or lug 27 which can en- gage in a corresponding slot 28 moulded on to the upper edge of the wall 23. The detent 27 it is shaped so as to permit it to be pushed into the slot 28, but to be difficult or im- possible to remove. Thus, when the indicator is in its correct position on the hose bend, the fastening arms 25 can be simply bent over and snapped into place to hold the indica- tor in position.

Referring now to Figure 3, it can be seen that the function of making the second curved wall 24 shorter than the first 23 is to enable the indicator to be fitted on any hose bend between 450 and 90 . The 90 degree bend is indicated by the first chain-dotted lines 30 while the 45 degree bend is indicated by the second chain-dotted lines 31. It will be appreciated that different angles can be accommodated by extending the length of the curved wall 23 at the same radius for greater angles the 90 , and by reducing the length of the second wall 24 for angles less than 45 . However, in practice, it will be evident that bends of less than 45 will not be less than the minimum radius, while bends extend- ing through greater than 90 will typically be accommodated by a pair of the indicators used end to end, as shown in Figure 4. It will be seen that, in this way, bends between 1350 and 1800 can be accommodated, and in this way any bends likely to be used in such and installation can be accommodated by one or two of the indicators in accordance with the invention.

Claims

1. A bend indicator for indicating conformity with a minimum curve radius of a bend in a flexible hose, comprising a base plate having a first concave side whose radius of curvature corresponds to the desired minimum curve radius, and a second, opposed, convex side, spaced apart from the first side, first constraint means upstanding from the base plate along the first side thereof defining a concave curved surface against which a curved hose may rest in use, and second constraint means upstanding from the base plate at at least the central part of the second side to engage a curved hose on the outer side thereof, and fastening means to retain a hose against the base plate between the first and second constraint means, in use.

2. A bend indicator according to Claim 1, wherein the first constraint means comprises a single curved wall upstanding from the base plate along the first side thereof.

3. A bend indicator according to Claim 1, wherein the first constraint means comprises a plurality of members upstanding from the base plate spaced apart along the 1 5 firsts edge thereof.

4. A bend indicator according to Claim 1, 2 or 3, wherein the fastening means hingedly extend from the first constraint means and are lockably engageable with the second constraint means.

5. A bend indicator according to Claim 1, 2 or 3, wherein the fastening means hingedly extend from the second constraint means and are lockably engageable with the first constraint means.

6. A bend indicator according to Claim 4 or 5, wherein latching means are provided to secure the fastening means to the respective constraint means.

7. A bend indicator according to any preceding claim, wherein at least the base plate and first and second constraint means are integrally formed as a plastics mould- ing.

8. A bend indicator, substantially as described with reference to, and/or as shown in, Figures 2, 3 and 4 of the drawings.

9. A flexible hose having a bend therein, the bend having fitted thereto a bend indicator according to any preceding claim.

10. A fire sprinkler system including at least one flexible hose according to Claim 9.