WO2009074999A2

WO2009074999A2 - Improved pipe belling/socketing device

Info

Publication number: WO2009074999A2
Application number: PCT/IN2008/000657
Authority: WO
Inventors: Naresh Jayendrarai Joshipara
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-10-22
Filing date: 2008-10-10
Publication date: 2009-06-18
Anticipated expiration: 2010-04-22
Also published as: WO2009074999A3

Abstract

An improved pipe belling/socketing machine divided into three sections consisting of a receiving end section, a heating section and a forming section, wherein the process of positioning of the pipe is done parallel to heating process, which significantly reduces overall cycle time of the process, with the help of a receprocating device.

Description

IMPROVED PIPE BELLING/SOCKETING MACHINE

FIELD OF THE INVENTION

The present invention relates to belling/socketing machine for PVC (Polyvinyl Chloride, uPVC, CPVC and Foam Core Multilayer) pipes.

More particularly, the present invention provides an improved process, and a machine, by which the geometrical accuracy of the socket of the pipe is consistently achieved, even at higher extrusion line speeds, in such a way that the process cycle time is considerably reduced thereby improving the productivity and throughput of the Pipe belling/socketing machine.

BACKGROUND OF THE INVENTION

Belling/socketing machine are widely used to join PVC pipes together by enlarging one end of the pipe, allowing other end of the next pipe to be inserted, forming a continuous line to carry liquids under pressure. To achieve pressure tight joints various industry standard methods exist in which the joints are sealed by solvent cement, rubber ring or other suitable means. Over the years, there has been a steady increase in the throughput capabilities of the extrusion line - line speed. Therefore the Belling/socketing machine output has to proportionately match with the increased throughput of extrusion line.

Belling/socketing operation involves Heating one end of the pipe and Forming the socket to the desired shape. Heating time depends largely on pipe diameter, PVC compound and pipe wall thickness. For a given pipe diameter and wall thickness, heating time can not be altered drastically by changing process parameters of heating process. Therefore it can be assumed that for a given pipe diameter and wall thickness heating time is fixed. Similarly, cooling time is also fixed at forming station, which can not be reduced drastically due to inherent properties of the pipe.

There are peripheral machine functions on which the accuracy of the socket, and the throughput are dependent. To name few of the peripheral functions such as positioning the pipe, transfer the pipe between various stations, speed of clamping, speed, of forming etc.

To achieve higher throughput of the Belling/socketing machine, these peripheral functions are the only functions which can be improved or eliminated. The increase in throughput poses numerous challenges so as to match the cycle time of belling/socketing with the throughput of the extrusion line, without sacrificing accuracy and repeatability of the socket geometry. The existing belling/socketing machines use several methods, such as using buffer between belling process and extrusion line; deploying two machines etc., to match throughput of the extrusion line. The belling/socketing machine with new concept obviates the necessity of providing buffer and/or introducing additional belling/socketing machine.

There are limitations of the peripheral processes which inhibits output of existing belling/socketing machines. The limitations can be broadly listed as the positioning accuracy for heating length, speed of transfer of pipe from one station to another, positioning accuracy at forming station, weight of pipe and repeatability of sensing and controlling devices.

During the operation of socket formation in the forming station, pipe is moved back and forth to achieve pre determined position with respect to the socket shape forming ^vtool. The movement of pipe increases cycle time and reduces the throughput of the machine. In the existing process sensing of the edge of the pipe is done while pipe is moving. This leads to inaccuracy and associated problems due to dynamic response of the system.

An additional positioning station might be placed between heating station and forming station, but leads to unnecessary cooling of the pipe at this station.

ADVANTAGES OF THE INVENTION To obviate the limitations associated with the existing pipe belling/socketing machines, the inventor has developed a machine for creating sockets in PVC pipes, which is extremely efficient and much more convenient than the existing machines. Upsides associated with the proposed machine are listed below.

The process of positioning of the pipe is done parallel to heating process, which significantly reduces overall cycle time of the process, with the help of a reciprocating device.

The proposed machine provides better sensing accuracy, for measurement of socket length along ' with repeatability offered by control device and efficacy of control system to pick and analyze measurement signals at various line speeds. In this case sensing is done, when the pipe is stationary.

The proposed machine offers better positioning accuracy of the pipe depending on the dimensions of the zone to be heated. Thus, plays an important role in heating operation. The pipe is positioned with very small movement of the pipe at low velocity.

OBJECTS OF THE INVENTION The main object of the proposed invention is to allow simultaneous operations of heating of pipe end as well as positioning of the pipe thus reduce overall cycle time of the entire belling/socketing process.

Another object of the proposed invention is to offer an improved machine which effectively matches the throughput of the extrusion line in proportion with the hourly production rate.

Another object of the proposed invention is to provide better sensing accuracy for measurement of socket length along with repeatability offered by control device 'and efficacy of control system to pick and analyze measurement signals at various line speeds. DESCRIPTION OF PRIOR ART

The proposed invention can best be understood with reference to a simplified discussion of the prior art. Refer Fig 1. The existing invention for pipe belling/socketing machine mainly comprises of three sections:

Receiving end section:- Pipe (1.1), Line of extrusion (1.2), pipe pulling device (1.3), pipe edge sensor(1.4), pipe support and transfer system (1.5).

Heating section:- Plurality of pipe heating ovens (1.6).

Forming section:- Socket shape formation tool (1.7), clamping arrangement (1.8), socket length control conveyor (1.9), socket length position control sensor (1.10).

The existing invention will now be described with the help of accompanying drawing as stated below:

Fig. 1 shows the schematic of pipe belling/socketing machine existing process. Referring to Fig. 1, Pipe (1.1) through the line of extrusion (1.2) is pulled by a pipe pulling device (1.3) positioned at the receiving end section of pipe belling/socketing machine, with the help of signal generated by pipe edge sensor (1.4). Pipe (1.1) at the receiving end section is transferred to heating section through pipe support and transfer system (1.5).

Heating section comprise of plurality of pipe heating ovens (1.6). Pipe (1.1) is heated in the plurality of pipe heating ovens (1.6) to make it soft at the socket formation end. Generally, heating is relatively a slow operation. The heated pipe (1.1) is further transferred to forming section through pipe support and transfer system (1.5).

In the forming section, in order to achieve correct position of the pipe (1.1) with respect to socket shape formation tool (1.7), pipe (1.1) end is sensed by socket length position control sensor (1.10) coupled through hard wiring to the controller (not shown in fig) applies correction to the position of the pipe with socket length control conveyor (1.9) and exact position is achieved by back and forth movement of the pipe (1.1). The movement of pipe (1.1) considerably increases cycle time and reduces throughput of the machine. Also sensing of the edge of the pipe (1.1) is done by sensor (1.10), while pipe (1.1) is moving, which leads to inaccuracy and associated problems due to dynamic response of the system. Also since the final positioning is done using braking of the pipe (1.1), the system response varies with respect to size of the pipe (1-1), inertia of the pipe (1.1), etc, and leads to variation in socket length. After achieving the positioning of the pipe (1.1), it is clamped in place by actuating clamping arrangement (1.8). Then the socket shape formation tool (1.7) is inserted into pipe (1.1), the socket is formed. The pipe (1.1) is cooled and to form proper shape external pneumatic pressure is applied in closed Cooling Chamber

(Not shown). After this, the socket shape formation tool (1.7) is withdrawn, the Pipe (1.1) is moved axially out by socket length control conveyor (1.9), and then the pipe (1.1) is delivered in the outlet bin.

As an alternative to above step of positioning and sensing of the pipe (1.1) by socket length position control sensor (1.10) and conveyor (1.9), sometimes an additional positioning station is introduced between heating station and forming station which leads to unnecessary cooling of the pipe. Due to numerous disadvantages associated with the existing machines as discussed earlier, the inventor has proposed a machine which truly and effectively overcomes all the limitations associated with the prior art. DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described with help of accompanying drawing as stated below.

Fig. 2 shows the schematic of improved pipe belling/socketing machine.

Fig.3 shows plan view of heating section which includes plurality of pipe heating ovens and socket length adjustment and control device.

Fig 4 shows the improved pipe clamping arrangement.

The proposed invention comprises of three sections:

Receiving end section:- Pipe (2.1), Line of extrusion (2.2), pipe pulling device (2.3), pipe edge sensor (2.4), pipe support and transfer system (2.5).

Heating section:- Plurality of pipe heating ovens (2.6), socket length adjustment and control device (2.7). Forming section :- Socket shape formation tool (2.8), Pipe clamping arrangement (2.9).

Referring to fig. 2, Pipe (2.1) through the line of extrusion (2.2) is pulled by a pipe pulling device (2.3), positioned at the receiving end section of pipe belling/socketing machine. Pipe edge sensor (2.4) placed at receiving end section, senses the edge of-pipe (2.1), and positions the pipe (2.1) for Heating Section. Pipe (2.1) at the receiving end section is transferred to heating section with the help of pipe support and transfer system (2.5) without any axial movement of pipe (2.1). Thus, pipe support and transfer system (2.5) transfers pipe (2.1) between adjacent sections without any axial movement of pipe (2.1). In the heating section, plurality of pipe heating ovens (2.6) come forward and heat the End portion of pipe (2.1)to make it soft at the socket formation end. After completion of heating time, socket length adjustment and control device (2.7) which is air/hydraulic/ mechanical cam actuated device, placed on one of the plurality of pipe heating ovens (2.6), adjusts the length and positions the pipe (2.1) with respect to socket shape formation tool (2.8) at which socket is to be formed and that position is sensed by a non contact type of sensor (not shown in fig-) Referring to Fig 3, the process of positioning of the pipe (2.1) is done parallel to heating process, which significantly reduces overall cycle time of the process. The adjustment over a wide range of socket length and position of the pipe (2.1) where socket is to be formed is done when the pipe (2.1) is stationary, which in turn gives better accuracy of position. Now, pipe (2.1) is further transferred to the forming section by pipe support and transfer system (2.5), without any axial movement of the pipe (2.1). Socket length adjustment and control device (2.7) can be in the form of mechanical, pneumatic or hydraulic actuation.

At forming station pipe (2.1) is clamped in place by air/hydraulic actuating pipe clamping arrangement (2.9). Refer Fig. 4. The Pipe clamping arrangement (2.9) is suitably modified, so that there is no axial movement required for the pipe (2.1) at the forming station.

Then the socket shape formation tool (2.8) is inserted into pipe (2.1), and the socket is formed. The pipe (2.1) is cooled and to form proper shape external pneumatic pressure is applied in closed Cooling Chamber (Not shown). After this, the socket shape formation tool (2.8) is withdrawn and then pipe (2.1) is directly delivered in the outlet bin. The invention described above, may be subject to numerous modifications and variations, all of which are falling within the scope of this invention idea. Moreover all the elements described above can be replaced by technically equivalent elements

By the improved process described above, it is specifically claimed in this innovation following improvements to be protected by copyright / patent.

Claims

1. An improved pipe belling/socketing machine divided into three sections wherein

First section being receiving end section which comprises of pipe through the line of extrusion pulled by a pipe pulling device, a sensor placed at receiving end section adjusts the position of pipe in such a manner that in the heating section plurality of pipe heating ovens will heat the end portion for socket formation of pipe as per requirement, pipe support and transfer system transfers pipe to adjacent sections;

Second section being heating section which comprises of plurality of pipe heating ovens wherein pipe end is heated for softening, at the end of heating process, the air/hydraulic/mechanical cam operated socket length adjustment and control device, positions the pipe at a given reference with respect to socket shape formation tool at the forming section; Third section being forming section which comprises of socket shape formation tool inserted into pipe for forming socket in pipe, pipe clamping arrangement is actuated by air/hydraulic system clamps pipe in place.

2. An improved pipe belling/socketing machine as claimed in claim I, wherein positioning of the pipe is done parallel to heating process.

3. An improved pipe belling/socketing machine as claimed in claim I wherein, socket length adjustment and control device adjusts the length and position of the pipe such that pipe socket shape formation is done when the pipe is stationary.

4. An improved pipe belling/socketing machine as claimed in claim I wherein, Pipe support and transfer system transfers pipe between adjacent sections without any axial movement of pipe.

5. An improved pipe belling/socketing machine as claimed in claims I and III wherein socket length adjustment and control device is a mechanical cam actuated device.

6. An improved pipe belling/socketing machine as claimed in claims I, III and V wherein socket length adjustment and control device is a hydraulic actuated device.

7. An improved pipe belling/socketing machine as claimed in claims I, III, V and VI where in socket length adjustment and control device is a pneumatic actuated device.

8. An improved pipe belling/socketing machine as claimed in claims I, III, V, VI and VII wherein socket length adjustment and control device is an electronic measurement device.

9. An improved pipe belling/socketing machine as claimed in claim I wherein positioning of the pipe is done at a slow speed, with stationary pipe, thereby improving accuracy and repeatability of the position of the pipe.

10. An improved pipe belling/socketing machine as claimed in Claim I wherein pipe claming arrangement is designed so that pipe end can be belled/socketed without axial movement of pipe.