| WO1981002461A1 | 1981-09-03 |
| NO134966B | 1976-10-04 | |||
| GB2078889A | 1982-01-13 | |||
| FR2129250A5 | 1972-10-27 |
| 1. | Method for connecting a branch conduit to an existing conduit through a valve of such a design that it in its open position shows a straight flow channel, preferably a valve of plug or ball type, the valve being connected to the conduit in sealing relationship against the fluid of the conduit by means of a connection part, the flow channel (8) of the valve being directed preferably tangentially towards the conduit (9), after which from a tool housing (16), connected in a sealing manner to the outlet of the valve, a cutting tool in the form of a piston provided with an edge (20) is moved in the flow channel (8) relatively to the conduit (9) and creates an opening in the portion of the conduit enclosed by the connection part whereupon the cutting tool being removed from the valve and the valve being closed, the tool housing (16) being dismounted and the branch conduit being connected to the valve outlet (11), characterised in that the tool housing (16) being fixed to the valve and the piston (12) being inserted into the flow channel (8) before the valve is fixed to the conduit (9), at which a cutting recess (13) arranged on one side of the piston encloses that portion of the conduit which is going to be removed to achieve the opening in the conduit and which portion at the removal of the piston from the flow channel through the action of a cutting edge (20), forming the border of the cutting recess (13) and working in the pullout direction will be cut out and enclosed in the cutting recess until the cutting tool is removed from the valve. Tool for carrying out the method according to claim 1, comprising a tubular housing (16), means (17) for fixing the housing to the outlet of a valve or similar, given the shape of a connection piece (15), the housing so forming an extention of a flow channel (8) of the valve, an axially movable piston (12) or the like arranged in the housing (16), a cutting edge (20) arranged on the piston, means (22,23) for the movement of the piston in the channel (8) at which movement the cutting edge (20) could be arranged to cut an opening in the portion of a conduit (9) which is enclosed by the valve or cooperating connection pieces characterised in that the cutting edge (20) of the piston (12) forming the border of the cutting recess (13) arranged on the side of the piston and being large enough to enclose the portion of the conduit to be removed, is designed to work in the pullout direction of the piston. |
TECHNICAL FIELD
The present invention relates to a method and means for connecting a branch conduit to an existing conduit through a valve of such a design that it in its open position shows a straight flow channel, preferably a valve of plug or ball type. More particular the invention is adapted for connecting branch conduits to conduits in systems filled with a fluid (liquid or gas).
BACKGROUND ART
Several methods and means for connecting branch conduits via valves to conduits in systems filled with a fluid are previously known. According to one method described in the Swedish patent No. 425 185 the valve is connected to the conduit in such a way that its flow channel will be tangential to the conduit. By means of a completely tight tool fixed to the outlet of the valve a piston could be moved into the flow channel by means of applied forces. The front end of the piston which is shaped as or provided with a separate cutting edge also comprises a portion formed as a hook. During the axial movement of the piston through the flow channel its front end provided with the cutting edge will cut an opening in the conduit. By means of the special design of the piston with a portion formed as a hook the cut-out portion of the conduit will be caught by and maintained in the piston. When the cutting operation has been finished the piston is brought back to its initial position, the valve is closed and the tool fixed to the outlet of the valve is removed together with the cut-out portion of the conduit. The tool is now replaced by means of a branch conduit, the valve is opened and the fluid could flow out into the branch.
The design of the front end of the piston with a gap between the cutting edge and a portion formed as a hook for maintaining the cut-out portion of the conduit, sets certain requirements on the conduit to which the branching is to be made. The material has to have a certain hardness so that the cut-out portion of the conduit will be fastened in the gap and follow the piston when this after completed cutting operation is withdrawn into the tool. If the conduit hasn't the assumed hardness but has been subjected to changes due to age or if it has been made red-hot for some reason e.g. while bending, so that its material properties has been changed, there is a risk that the cut¬ out portion of the conduit will be dropped into the conduit. If you are unlucky it could for instance follow the fluid flow and be caught in a valve so that this will be out of order.
DISCLOSURE OF INVENTION
The object of the present invention is on the one hand to eliminate the dependence of the method of the material properties of the conduits and on the other hand to simplify the cutting tool and its handling. This is achieved in that the method and the means according to the invention have been given the characteristic features of the following claims.
BRIEF DESCRIPTION OF DRAWINGS
The invention will be described more in detail in connection with the enclosed drawing.
Figure 1 shows a sectional view of a ball valve fixed to a conduit. The valve is of a design preferred for the carrying out of the method. Further, also in sectional view, an embodiment of a cutting tool for the carrying out
of the method. The tool which is fixed to the outlet of the valve is shown in the initial position.
Figure 2 shows the same valve and tool as in figure 1 but after the cutting in the conduit.
PREFERRED EMBODIMENT
The ball valve shown in figure 1 comprises a housing of two parts 1 and 2 in which housing a ball 3 provided with a through hole is arranged. The ball which is fitted between two stuffing washers 4 and 5 is provided with a recess 6 reachable from the outside if the plug 7 is removed. By means of a suitable tool the ball can be rotated in order to adjust or cut off the flow in the flow channel 8. Several plugs 7 with corresponding recesses 6 in the ball could be arranged in the valve housing making it possible to operate the ball from the side which has the best accessibility. The housing part 1 is formed as a conduit connection and encases the conduit 9 shown in cross section and to which the housing is fixed by means of the clamp 10. The outlet 11 of the valve is arranged in a connection piece 15 located in the housing part 2 to which a branch conduit, not shown, is to be connected. In stead of a branch conduit a tool is connected to the valve in the figure. The tool comprises a housing 16 in which a piston 12 is slidably arranged. The tool housing 16 is fixed to the connection piece 15 by means of a nut 17 arranged around one of its end portions, the nut engaging the screw thread of the connection piece 15. The piston is inserted into the flow channel 8 of the valve until it touches the bottom in the .housing part 1. In this position, a cutting recess 13 arranged on one side of the piston 12, is aligned with an opening in the housing part 1 through which opening a portion of the conduit 9 extends into the flow channel 8
and the cutting recess 13 when the valve provided with a tool is fixed to the conduit.
The making of a hole in the conduit 9 is carried out by means of forces applied to the piston 12. The nut 22 arranged on the threaded portion 23 of the piston is tightened against the end portion of the housing 16. At this the piston 12 is moved towards the position shown in figure 2. The lefthand portion of the cutting recess 13 shaped as an edge 20 cuts an opening in the conduit and removes the cut out portion 14 of the conduit 9. When the piston has reached the position shown in figure 2 and the conduit is filled with a fluid the valve is closed by turning the ball so that its through hole will end up perpendicular to the flow channel 8 before the cutting tool is removed. The stuffing washer 25 and the sealing ring 26 prevent fluid in the conduit 9 from passing the tool and the quantity of fluid that after the valve has been closed remains in the outlet, and mostly is lost when the tool is removed, is of no practical importance
When the tool has been dismounted from the valve the cut¬ out portion is easily removed from the cutting recess 13.
The shown cutting tool could easily be changed to fit different types of forces acting on the piston. If the slot 18 is eliminated and the nut 22 is substituted with a piston, movable in the housing 16, which in that case must be prolonged and provided with an end stop, the necessary force could be achieved from an explosive cartridge arranged in the tool housing at the end connected to the valve or by means of pressure from a hydraulic pump. The tool also comprises guiding arrangements, not shown, which secure that the cutting recess 13 gets a correct position in relation to the conduit 9.
By means of the proposed method for connection of branch conduits a reduction of the costs is achieved due to the fact that the piston during the cutting operation only has to be moved in one direction.