Fitting to connect water pipes

Abstract

A fitting to interconnect water pipes or to connect pipes with valves or mountings. The connector housing has an O-ring seat, constituting two walls of a groove for an O-ring. The fitting comprises a clamping sleeve, having a first end provided with a flange, which forms a third wall of the O-ring seat groove. The flange is retained against the coupling housing by a nut screwed by hand onto outer threads on the coupling housing. The clamping sleeve is adapted to be clamped against a pipe which is inserted into the clamping sleeve, and the O-ring seals against the outer surface of the pipe.

Claims

1. A fitting to interconnect water pipes or to connect pipes with valves or mountings, the fitting comprising: a coupling housing; an O-ring; a nut; wherein the coupling housing comprises: an internal bore in which at the end of the bore is formed an O-ring seat, constituting two walls of a groove for the O-ring; and an external thread on which the nut is received; a clamping sleeve comprising a first end provided with a flange, said flange forming a third wall of the O-ring seat groove, the flange being retained against the coupling housing by the nut, the clamping sleeve being adapted to be clamped against a pipe which is inserted into the clamping sleeve, and that the O-ring, when the pipe is mounted, seals against the outer surface of the pipe; wherein the clamping sleeve is fixated to the coupling housing by the nut before the pipe is inserted into the clamping sleeve; and wherein the pipe is fixated to the fitting via squeezing of the clamping sleeve forming a groove in the clamping sleeve.

2. The fitting according to claim 1, wherein the coupling housing bore has a portion axially inside of the O-ring seat having a diameter corresponding to the pipe outer diameter.

3. The fitting according to claim 2, wherein the coupling housing bore has a portion axially inside of the portion of a diameter corresponding to the pipe outer diameter, having a diameter corresponding to the pipe internal diameter.

4. The fitting according to claim 1, comprising a supporting sleeve which is adapted to be inserted into the pipe and that the supporting sleeve has a flange at its outer end with an outer diameter corresponding the pipe outer diameter.

5. The fitting according to claim 4, wherein the flange forms a part of a seat for a second O-ring, located between the tube end and the flange.

6. The fitting according to claim 5, wherein the support sleeve has a radial abutment surface for bearing against the pipe end, the pipe end, the flange and a cylindrical portion of the sleeve forming the walls of a groove with fixed width for the second O-ring.

7. The fitting according to claim 1, wherein the coupling housing and the nut is made of a plastic material.

8. The fitting according to claim 1, wherein the coupling housing is a part of a connector piece, a valve, a T-piece, or an elbow.

9. A method of providing connection of a coupling housing and a pipe, wherein the coupling housing has an internal bore where, at the outer end of the bore is formed an O-ring seat, constituting two walls of a groove for an O-ring, and having an external thread for receiving a nut, the method comprising: placing the O-ring in the O-ring seat; placing a clamping sleeve having a flange with the flange towards the O-ring; screwing the nut onto the external thread by hand until the flange is clamped between the nut and the coupling housing; inserting the pipe through the clamping sleeve and into the coupling housing and bringing the outer surface of the pipe to bear against the O-ring; squeezing the clamping sleeve to fixate the clamping sleeve onto the pipe; and wherein the squeezing forms a groove in the clamping sleeve.

10. The method of claim 9, wherein the squeezing of the clamping sleeve is performed via clamping pliers.

Description

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

(1) The invention will now be described referring to a specific exemplary embodiment, with reference to the accompanying drawings, where:

(2) FIG. 1 shows a fitting according to the invention split into individual components,

(3) FIG. 2 shows the fitting assembled and ready to receive the pipe ends,

(4) FIG. 3 shows the pipe ends of two different types of pipes connected to the fitting and

(5) FIG. 4 shows a fitting connected to another type of pipe.

(6) FIG. 1 shows an embodiment of the fitting according to the invention split into its components. The fitting comprises a housing 1 having a through bore with different inner diameters, as follows: Section 1a has a diameter corresponding to inner diameter of the pipe to be connected, Section 1b has a diameter corresponding to the external diameter of the pipe to be connected, and Section 1c has a diameter corresponding to the outside diameter of a first O-ring 2.

(7) The illustrated fitting housing has two identical ends 1e, each with a portion 1b and 1c.

(8) On the outside, the housing has a thread 1d at each end for a nut 4.

(9) The fitting housing 1 can be manufactured by a simple moulding method of the plastic, wherein a non-rotating shaft is placed at each end of the tool, forming sections 1a, 1b and 1c. The outer part of the tool is split along a centre-line and forms the outer shape, including the threads 1d for the nut 4.

(10) Further illustrated, an O-ring 2, which can be made of EPDM (ethylene propylene diene monomer) with peroxide, and the exterior can be coated with silicone for minimum friction. Such an O-ring will withstand high temperatures. However, also other types of rubber, natural or artificial, may be used as suitable.

(11) A clamping sleeve 3 is provided by forming an outwardly projecting flange 3a at one end thereof. At the other end 3b, the pipe is chamfered internally. The clamping sleeve is preferably made of stainless steel.

(12) The nut 4 is preferably also made from a thin stainless tube, with threads 4a formed on the inside, e.g., by rolling. At one end an inwardly extending flange 4b is formed.

(13) FIG. 2 shows pre-assembled the state in which it is intended to supply the fitting. With all the components shown in FIG. 1 factory-assembled, it will be both quicker and easier for the plumber to make a connection with a pipe. Consequently, assembly has taken place where the O-ring 2 is first placed at the interior seat 1c. Then the clamping sleeve 3 is placed against the O-ring 2 and the end 1e of the fitting housing 1. Finally, the nut is mounted over the clamping sleeve 3 and the housing 1, and screwed by hand until it firmly grips the flange 3a of the clamping sleeve 3. The flange 3a thereby forming a third wall for the O-ring 2 and providing a complete support for the O-ring 2. The O-ring will seal against the pipe as will be explained below. As the flange 3a has an outer diameter corresponding to, i.e. is slightly smaller than, the internal thread of the nut 4a, the flange 3a will abut the end 1e of the housing 1. This provides a correct fixed width of the groove for the specific material thickness of the O-ring 2.

(14) In FIG. 2 is also shown a support sleeve 5, which preferably is a thin-walled stainless tube with an increased diameter portion 14 near one end and an outwardly extending flange 13 at the same end. The increased diameter portion 14 forms at, an outer surface, a seat for a second O-ring 11. A transition between the increased diameter portion 14 and the major part of the sleeve 5 forms an abutment surface 12 to rest against the end of a pipe 6. The support sleeve 5 with the second O-ring 11 is mounted within a plastic pipe 6, for example of the type Wirsbo, as explained below.

(15) The second O-ring 11 is mounted on the support sleeve 5 and then the sleeve 5 is inserted into an end of the plastic pipe 6 until the abutment surface 12 abuts the end of the pipe 6. Thus is formed a groove consisting of surfaces of the flange 13, the increased diameter portion 14 and the end of the pipe 6. This groove has a fixed width adapted to the dimension of the O-ring 11. This end of the pipe 6 with the support sleeve 5 is then pushed into the coupling housing 1, as shown in FIG. 3, and as will be explained further below.

(16) At the opposite end of the coupling is shown a pipe 7 made of metal, such as stainless steel, copper, or other metals. How this pipe is connected to the coupling housing 1 will also be explained below.

(17) FIG. 3 shows the coupling housing 1 with its associated parts, O-ring 2, clamping sleeve 3 and nut 4, which have been factory fitted at each end. The plumber has mounted the support sleeve 5 with O-ring 11 into the plastic pipe 6, and then inserted the pipe 6 into the coupling housing until the flange 13 reaches the inner end of the section 1b and abuts the transition to section 1a.

(18) On the opposite side, the left side of FIG. 3, the plumber has inserted a pipe 7 of stainless steel, without a support sleeve. Then he squeezes the clamping sleeves 3 with a pair of pliers, such as of the type Mannesmann. This results in dented grooves 9, shown in both the clamping sleeves 3. On the inside, this dented groove presses against the pipe 5, 7 and fixates the pipe 5, 7. This way of mounting imposes no twisting of the pipes during the mounting. There is no stress on the fitting irrespective of the materials used.

(19) As shown, the end of the fitting connected to the plastic pipe 6 has two O-ring seals. The fitting end with the metal pipe 7 has one O-ring seal. There is no stress imposed on the plastic coupling housing 1, which in conventional connectors can be a problem.

(20) As will be explained now, a very quick dismantling of the connections can be made, without tools, and without any deterioration of the fitting components. To disassemble, either one side or on both sides of the fitting, all that is needed is to unscrew the nut 4. The nut 4 is tightened by hand at the factory, and will therefore not sit very firmly.

(21) When the nut 4 is unscrewed, it is easy to pull the pipes 6, 7 out of the coupling housing to replace O-rings. The clamping sleeves will now be attached to the pipes, 6, 7, and will follow these when they are pulled out. The nut 4 will sit around the pipe 6, 7, and the clamping sleeve 3 will prevent the nut from sliding off the pipe 6, 7.

(22) There is no need to remove the clamping sleeves 3. The pipes 6, 7 can simply be refitted to the coupling housing 1 with the same clamping sleeves 3 and the same nuts 4. The nut 4 will be tightened by hand again.

(23) This means that replacement of O-rings and valves can be done without any use of tools.

(24) A fitting according to the present invention has been tested at a pressure of 60 bar without showing any weakness.

(25) FIG. 4 illustrates that the coupling also can be used together with a pipe 10 in which there is formed a bead 10a on the pipe 10. This results in a fitting similar to some of the prior art described above. In this case, the coupling housing 1 is provided with an O-ring 2, but is not equipped with a clamping sleeve 3. Instead, a third wall of the O-ring groove is formed by the bead 10a of a prefabricated pipe made of a thin stainless steel or copper material. In an additional rolling operation, the bead 10a of this pipe 10 forms a double wall where one side supports the O-ring 2, and the other side abuts the nut 4.

(26) The fitting of the invention may be a connector for connecting two pipes, or it can be part of a valve to which one or more pipes can be connected.