The present invention relates to improvements in or relating to valves. In particular, it relates to valves which are insertable into existing pipes or other lines without disconnection of the line.

There are many situations in systems involving flow of a fluid through a pipe or other line, such as water supply lines and heating pipes carrying water; refrigeration, air conditioning or gas pipes; in which it is necessary terminate the fluid flow. For example, a temporary termination may be required in order to effect a repair or to modify the line, to include a new branch or replace a component such as a pump. Typically even simple repairs or modifications require complete shut down and drainage of the entire system. It is therefore desirable to be able to insert one or more valves in the pipe or line in order to isolate a small section of the system, allowing the remainder of the system to continue to be operated normally, or at least avoiding the need for complete draining of the system.

US 4 552 170 and GB 2 352 281 describe two such valves. The valves have a broadly similar construction and comprise a valve body which comprises two halves which are clamped around the pipe. One of the halves includes a threaded bore into which is screwed a pipe cutter element. The pipe cutter element is rotated through the bore until it contacts and then cuts through the upper half of the pipe wall. In GB 2 352 281, the pipe cutter element includes a further threaded bore into which is then screwed a valve element which has an expanding rubber seal at its lowermost end which compresses upon continued rotation of the valve element to fill and seal the pipe. In US 4 552 170, the pipe cutter element is adapted to cut through both the upper and lower portions of the pipe wall such that the cutter element itself forms the valve element.

Both designs include a rotating cutting element. As they cut into the pipe, they tend to produce swarf which then passes into the fluid and around the system. This can cause substantial damage to sensitive components present in the system, particularly those with moving parts such as pumps. The present invention seeks to avoid this problem.

In its broadest sense, the present invention provides a valve for insertion into a fluid pipe or line, which valve comprises a valve body having a bore for receipt of the pipe or line and being sealingly mountable upon the pipe or line. The valve further comprises a blade mounted for linear movement within the valve body between a retracted position and an extended position in which the blade prevents flow of fluid through the pipe or line.

Preferably, the blade is adapted, upon first use of the valve, to cut substantially through a pipe or line received by the valve body.

Preferably, the blade is mounted for a linear movement within the valve body within a pair of opposed slides or grooves.

Preferably, the blade is mounted upon a shaft. Preferably, the shaft is threaded and mounted for rotation within a correspondingly threaded bore formed in or on the valve body.

Preferably, the blade includes a distal projection.

The above and other aspects of the present invention will now be described in further detail, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a lateral cross-sectional view of an embodiment of a valve in accordance with the present invention in an operatively open configuration; Figure 2 is a lateral cross-sectional view of the valve of Figure 1 in an operatively closed configuration;

Figure 3 is a dissembled front cross-sectional view of the valve of Figure 1; and

Figure 4 is a disassembled side cross-sectional view of the valve of Figure 1.

Referring to Figures 1 and 2, there is shown, in lateral cross-section, an embodiment of a valve 10 in accordance with the present invention. The valve 10 has a valve body 11 which comprises a matched pair of lower and upper (distal and proximal) valve body halves 12,13 having a bore 15 (Figures 3 and 4) therethrough. Valve body halves 12, 13 are clamped, in use, with bore 15 around a pipe or other line 14 and the two halves held together by appropriate means such as bolts or screws or external clamping means (not shown).

Valve body 11 is provided with seals as appropriate to prevent fluid loss in use. In the embodiment shown, a longitudinal seal or gasket 21 is positioned between the upper and lower valve body halves 12,13. In preferred embodiments, the valve is also provided with a seal membrane or gasket 22 which is wrapped around the pipe 14. In certain embodiments, gaskets, 21, 22 are combined in to a single gasket. Seals may also be provided on either side of the position at which the pipe will be cut.

Mounted within upper valve body half 13 is a gate or blade 23 of substantially the same distal shape and dimensions as bore 15 through which the pipe 14 passes. Blade 23 is constrained to move in a linear fashion within upper valve body half 13 suitably between opposed slides or grooves 24 formed within upper valve body half 13. Movement of blade 23 along grooves 24 can be achieved by any suitable means. In the embodiment shown, blade 23 is mounted for free rotation upon a lower end of threaded shaft 25, which threaded shaft 25 is mounted within a corresponding threaded nut or valve head body 26 (in the manner of a leadscrew) such that rotational motion of shaft 25 is converted into linear motion of the shaft and thereby of blade 23. Suitably, shaft 25 is rotated by means of a handle or actuating knob 31. Optionally, (as shown) blade 23 is shaped to include a projection or point 30 at its distal end (as seen in Figure 1) to assist the blade in puncturing pipe 14, in use.

The construction of the valve can be seen more clearly from Figures 3 and 4. Upper valve body half 13 and valve head body 26 can be formed as a single component or, as shown, as two separate elements in which upper valve body half 13 includes an aperture 32 for mating receipt of valve head body 26, suitably by means of threaded coupling.

The moving component of the valve is formed by blade 23 coupled to shaft 25 the lower portion of which is provided with threads 33 (illustrated schematically) which cooperate with a correspondingly threaded female bore 34 through valve head body 26. Blade 23 is mounted at the lower end of threaded shaft 25 for free rotation by means of a blade holder 35. Blade 23 and blade holder 35 are mounted on threaded shaft 25 once the shaft has been engaged with bore 34. A sealing gland 40 (Figures 1 and 2) ensures a water-tight assembly.

Upper valve body half 13 includes a slot 41 through which, in use, blade 23 passes.

In alternative embodiments, blade 23 has a diameter which is selected to be between the inner and outer diameters of the pipe 14 such that the pipe 14 is not completely severed and remains partially intact in the lower portion thereof.

In use, upper and lower valve body halves 12, 13 are clamped around pipe 14 and secured in place, with seals and gaskets 21,22 in position. Handle 31 is rotated causing blade 23 to move linearly from a disengaged position to the fully engaged position shown in Figure 1, cutting into pipe 14 as it descends. In the fully engaged position (Figure 2), blade 23 acts to seal pipe 14 from the flow of fluid therethrough.

Work on the system can then be carried out, upon completion of which, blade 23 can be retracted to allow fluid flow to resume. The valve is then left in place and can be used conventionally as a gate valve.