FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patent Rules, 2003
Provisional Specification
(See section 10 and rule 13)
A novel joint made in pipes with integral male and female ends
Jain Irrigation Systems Ltd.
Indian company registration under the Indian Companies Act, 1956 Plastic Park, NH. No. - 6, Bambhori, P.B.72, Jalgaon 425001 Maharashtra State, India

The following specification particularly describes the invention and the manner in
which it is to be performed.


A novel joint made in pipes with integral male and female ends
FIELD OF INVENTION:
The present invention relates generally to the field of forming joints for plastic tubing. More specifically, the present invention relates to permanent, leak-proof joints in polyolefin tubings made with integral male and female ends and a method of forming such tubings and joints.
BACKGROUND OF INVENTION:
Quick connect pipes are being in use for sprinkler irrigation system since last so many years. In this system the pipes are extruded on an extrusion machine, male and female ends are produced by injection molding and these molded ends are welded to a pipe's plain ends to make the pipe suitable for joining with other pipes. The male and female ends can be welded to the pipe in a number of ways such as butt fusion welding, socket fusion welding etc. The pipes thus fitted with male and female joints are easily connected with and disconnected from each other. A clamp is used to hold the joints thus formed withstand pressure and sealing rings are used to make the joints leak-proof.
The ideal sprinkler irrigation piping system is designed in such a way that -
• It withstands the applied pressure.
• It is easy to install and dismantle in field.
• The joints are leak-proof
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• The pipe ends, which are generally prone to damage, are unbreakable.
• The pressure drop should be minimum.
• The system must be cost effective.
The existing piping systems used for sprinkler irrigation fulfill the above first three requirements, however, these systems suffer from drawbacks such as:
• The welded male and female joints can fail if proper welding procedures are not
followed.
• The welded joints cause restriction in flow of water, which results in pressure drop across the joint.
• The joints are created using injection molding technique thus requiring heavy investment for injection molding machine and equipments, in a business that otherwise would be operating on a extrusion technique.
• A separate huge inventory of molded articles needs to be maintained to fulfill requirements on time.
• A large number of welding equipments required to manufacture in quantities.
• It also requires additional post operation facility to machine the required groove in molded female end which also generates waste.
• In addition to above all it requires skilled manpower without which the good quality welded joints can not be produced.
• Weld quality can vary dependent upon the operator skill
In order to overcome the restriction-to-flow drawback, there have been attempts to
make inner end of pipe at the plane of joint as smooth as possible by debeading
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operation. This helps in reducing the flow restriction, which ultimately reduces pressure drop. However, this method is not effective in sprinkler piping system as the pipes used are generally thin walled and debeading operation could risk a reduction of the weld joint strength, resulting in weld failure. Also debeading operation is time consuming and thus increases the cost of the irrigation system.
There have been attempts to eliminate the post operation of machining groove in molded female end. This did not succeed work due to the uneven shrinkage properties of polyolefin during molding with the change in article wall thickness. The uneven shrinkage results in problems relating to sealing and Assembly.
There is therefore a need to provide a system of joints which will fulfill all the requirements as specified above for long life working of piping system used in sprinkler irrigation at lowest cost, and which will not suffer from any of the drawbacks mentioned above.
OBJECTIVES AND ADVANTAGES:
Accordingly the objectives & advantages of the present invention are as described below.
An Objective of the invention is to provide system of joints for a irrigation system comprising pipes that are provided with integral male & female ends so as to:
• Eliminate the need for injection molding of male & female ends.
• Eliminate the need for welding activities.
• Eliminate the risk of welded joint failure.
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• Minimize the pressure drop across the pipe joints.
• Eliminate the coupler grooving activities.
• Eliminate the material wastages during female end groove machining.
• Ensure that the system will withstand the pressure applied in the system and is leak proof
• Ensure that the system is easy to install & dismantle in field
• Ensure that the system is cost effective.
BRIEF DESCRIPTION OF FIGURES:
Figure 1 shows longitudinal section of the assembled pipe joint having integral male & female ends.
Figure 2 shows longitudinal section of pipe at male end.
Figure 3 shows longitudinal section of pipe at female end.
Figure 4 shows isometric view of assembly showing the integral male & female pipe ends in assembled condition.
SUMMARY OF THE INVENTION:
The invention describes permanent, leak-proof joints in polyolefln tubings made with integral male and female ends and a method of forming such tubings and
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joints. In the sprinkler irrigation industry, such pipes are made out of polyolefins and are known as quick connect joints.
The invention provides a process of manufacturing the integral male & female ends of extruded pipes. This is characterized in such a way that the ends of extruded pipe are heated & expanded in a known & controlled manner to form either a male or female socket having a diameter 0.5 to 5% in excess of the desired final pipe diameter (this is independent of the material). The resulting socket is cooled and subsequently compacted in a pressing tool to have a diameter such that when released from the pressing tool, the socket will undergo an elastic expansion to have the desired final diameter.
Joints using the pipes provided with integral male and female ends are constructed using a push fit principle. Sealing ring is used to make the joint leak proof, plastic / metal clamps are provided to sustain the longitudinal forces imposed on the joint. Collar of integral male is provided to provide holding surface to clamp resisting longitudinal forces. The joint is simple in its construction, easy to assemble in field & cost effective.
LIST OF PARTS:

Part No. Name Part No. NAME
1. Male End of Pipe 6 Holding Clamp
2. Female end of pipe 7, Male Entry length
'■1 Sealing ring groove 8 Female Entry length
4. Collar at male end 9 Depth of Engagement
5 Sealing ring
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DETAILED DESCRIPTION OF THE INVENTION:
The invention describes a method of making integral male and female ends on extruded polyolefin pipes and leakproof and pressure-withstanding joints using such pipes.
The most preferred embodiment of the invention is now described.
In the preferred embodiment of the invention, integral male (1) end is inserted into the integral female (2) end of pipe and the joint is held together with the help of holding clamp (6). This is shown in Figure 1. The joint further comprises a good sealing and holding arrangement that will withstand pressure in the field situation. The arrangement comprises provision of sealing ring (5) placed inside the sealing ring groove (3) to prevent fluid leakage & holding clamp (6) to provide secure locking against axial movement due to fluid pressure.
A novel feature of the invention is the integral male & female ends of pipe. Instead of using injection molded pieces welded to pipe ends, as is the current practice in the related industry, the inventor have advantageously made a pipe with integral male (1) & female (2) sockets. The integral male (1) & female (2) sockets are formed after the pipe extrusion process. The integral female (2) socket has corresponding sealing ring groove (3) on its inside surface and the integral male (1) socket has corresponding collar (4) on its external surface. The inventors have found that the collar (4) advantageously secures the pipe against the axial movement and acts as stopper for male (1) end's entry length (7) into the female (2) end.
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Figure 2 shows longitudinal section of pipe taken through a typical male (1) end. The male (1) end shows the formed collar (4) and male entry length (7). The male entry length (7) sits inside the female (2) end compressing the sealing ring (5) and making the joint leak-proof.
Figure 3 shows longitudinal section of pipe taken through a typical female (2) end. This shows the sealing ring groove (3), female entry length (8) and depth of engagement (9). The female entry length (8) helps in doing proper alignment during assembly and depth of engagement (9) is important for leak-proof joint.
Figure 4 shows an isometric view of assembly showing the integral male & female pipe ends in assembled condition.
To construct the joint as disclosed in the preferred embodiment, a sealing ring (5) is placed inside the sealing ring groove (3) provided inside of the integral female (2) socket of pipe & then the integral male (1) end is inserted into integral female (2) socket of another pipe till the collar (4) touches to female entry (8) length, then the holding clamp (6) is put in place which ensures that the pipe remains held in place under the axial forces. The resultant joint is Leak-proof without any possibility of breakage.
The inventors have found that the novel quick connects integral pipe joint described in the present invention has the advantages such as:
• It eliminates the injection molding of male & female ends.
• It eliminates the welding activities.
• It eliminates the risk of weldedjoint failure.
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• It minimizes the pressure drop as there are no rough surfaces or protrusions that could restrict the flow.
• It eliminates the coupler grooving activities.
• It eliminates the generation of wastages during female end grooving.
• It withstands the pressure applied in the system and is leak proof.
• It is easy to install & dismantle in field
• It is cost effective.
Inventors have carried out a number of field tests in support of the claimed advantages of the invention. Table 1 shows the actual test results of the joint
prepared with the above method, which indicates fitness to the purpose.

No. Test description Test pressure kg/cm2 Test duration Hrs. No. of samples tested remark ■
1 Leakage test 0.5 1 5 No leakage found
2 Hydraulic proof test 6.4 1 5 No leakage found
3 Holding attachment 6.4 1 5 No deformation found


Several embodiments of the invention are possible. On this 6th Day of August, 2008

To The Controller Of Patents The Patent Office, Mumbai

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Tase, Vijay Sharatchandra Patent Agent No. IN/PA 987 Patent Agent for the Applicant