WO2011117652A2

WO2011117652A2 - Electrofusion clamp

Info

Publication number: WO2011117652A2
Application number: PCT/GB2011/050612
Authority: WO
Inventors: Nigel James
Original assignee: Electro Services Limited
Priority date: 2010-03-25
Filing date: 2011-03-25
Publication date: 2011-09-29
Also published as: GB2478964A; GB201005008D0; WO2011117652A3

Abstract

An electrofusion clamp (10) including; a) a first clamp means (12) including a first clamp member (22) and a second clamp member (24) wherein the first clamp member is moveable with respect to the second clamp member such that the first clamp means is moveable from a first open or undamped position to a second closed or clamped position; and b) a means (28,30,32,34) for detecting if the first clamp means is in the open position or the closed position.

Description

Electrofusion Clamp

Field of the Invention The present invention relates to a method and apparatus for use in the electrofusion welding of plastic components together, said plastic components may include plastic pipes and plastic coupling components. It is particularly applicable to an electrofusion clamp and associated apparatus and method for monitoring both the energy input and time to create the electrofusion weld and the time that the weld is allowed to cool and set for before the electrofusion clamp is removed. It is also particularly applicable to an electrofusion clamp which includes a means for scraping the surfaces of the plastic component taking part in the electrofusion weld. It is also particularly applicable to an electrofusion clamp which includes a hydraulic means for moving a first clamp means relative to a second clamp means.

Background to the Invention

Pipes made of plastics material are used extensively in industry and in construction. Many applications now use pipes made from plastics materials such as polyethylene and polypropylene rather than metal. Such applications of this type of pipework include petroleum installations such as garage forecourts, mains gas and water pipes and domestic gas and water pipes.

Electrofusion welding involves taking two components made of a plastics material, being thermoplastics. The components need to be able to fit together without any substantial gap between them. For example if you are joining two lengths of plastic pipe together a coupling component is generally used which is a tight sliding fit over the ends of the two lengths of pipe. At or near the surface of one of the components there is provided a heating element, usually in the form of heating windings (ie a thin coil of wire, with known heating and resistance properties). The ends of the heating winding are each provided with an electrical terminal through which electricity can be passed. When electricity is passed through the heating winding the winding heats up and melts the surrounding plastic of the component which the heating winding is located in and the surround plastic in the other component which it is to be connected to. The heated melted plastics merge with each other to create the weld in effect becoming one piece of plastics. Once the electricity being passed through the heating windings is stopped the heating windings cool down and the plastics material cools down and sets back to a solid plastics material wherein the two components have been welded together. It is very important that the weld or joint formed between the two components is fluid tight, to the fluid to be transported though the pipe ie gas tight, water tight or petroleum tight.

It has always been important to record the jointing parameters i.e. the length time that the electricity was passed through the heating windings, the current voltage passed through the heating windings, location of the weld, date and time and operator who created the weld. Previously this data was recorded manually, but it is now possible to store this information automatically in welding machines which are used to pass electricity through the heating windings. Such information can be stored within the integral memory of the welding machine for later retrieval as required.

It has also always been important to hold the two components in position whilst the weld is being created to create a strong weld. This is important for two reasons, firstly so that no slippage occurs between the two components and the weld occurs in the desired location and secondly to that the components do not warp or bend as they are heated. Usually the two components are held in position using a clamp.

The problem is that although the clamp should be kept in position not only while the electrofusion process is taking place, but also for a period of time afterwards whilst the weld is cooling. However, this is not always the case and sometimes the clamp is removed prematurely. Removing the clamp prematurely before the weld has cooled may result in the components slipping, warping or bending which effects the integrity of the weld created. Therefore there is a need to be able to determine whether a clamp has been removed prematurely, either during the heating or the cooling process.

In addition in order to provide a good weld between the two components the surface being welded which does not contain the electrofusion windings is scraped before the weld is created. The scraping occurs so that fresh plastics is exposed which does not contain any contaminants which might effect the integrity of the weld to be created. The problem is that carrying around sharp implements on site can be dangerous. It is also important to be able to prove that the pipes have been scraped prior to the electrofusion welding taking place, as a lack of scraping can result in an inferior or failed weld.

Summary of the Invention

According to a first aspect of the present invention there is provided an electrofusion clamp including; a first clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the first clamp means is moveable from a first open or undamped position to a second closed or clamped position; and a means for detecting if the first clamp means is in the open position of the closed position and preferably a means for recording if the first clamp means is in the open position or the closed position. This allows for the first time a way of noting and recording when a clamp is in a clamping position not only whilst an electrofusion weld is being carried out (ie electricity is being passed through the heating windings of a plastic component) but also during the cooling time required after the weld has occurred. It is important to keep the clamp in place whilst the weld is being carried out as the plastic component becomes hot and melts at the point of the weld and also becomes warm and malleable away from the point of the weld. To make sure that there is no movement whilst the weld is being carried out the two components being welded together are clamped together. This assists with aligning the two pieces and for making sure in the case of pipes for example that the still round after the welding has taken place. After the weld has taken place the plastic will need to cool and set in position before the clamp is removed. There has been no way before of detecting and/or recording whether the clamp has been removed prematurely before, which is now allowed for in the present invention. It is important to know if a clamp has been removed prematurely as this is likely to effect the integrity of the weld and therefore the seal and whether the joint is "failed" and should be remade. This is already important in petroleum and gas fields and is also becoming increasingly important to have seals with good integrity in the water field where water suppliers are increasingly under pressure not to "lose" water especially when the public are being told to look after it if there is a shortage. It is also becoming very important to produce evidence (preferably computer evidence and data) to prove that the joints have been made to the correct standards, hence technology exists that records the weld being created but nothing existed previously to monitor the weld during the cooling period after the weld has been created. In one alternative the means for detecting if the first clamp means is in the open position or the closed position includes a first electrical contact located on the first clamp member and a second electrical contact located on the second clamp member such that when the first clamp means is in the open position the electrical contacts are not in contact with each other and when the first clamp means is in the closed position the electrical contacts are in contact with each other. In this case when the first electrical contact is in contact with the second electrical contact an electrical circuit is completed, and the means for recording if the first clamp means is in the open position or the closed position records when the electrical circuit is completed and when the electrical circuit is not completed. The first clamp member of the first clamp means may include a first electrical terminal electrically connected to the first electrical contact. This enables in the case of only a single clamp means being provided a circuit to be created from the detecting and recording apparatus which may be either integral with the electrofusion clamp or separate there from to the first clamp member via the first electrical terminal to the first electrical contact to the second electrical contact, when the clamp means is in the closed position, to an second electrical terminal which is electrically connected to the second electrical contact and preferably located within the second clamp member which goes back to the detecting and recording apparatus to complete the circuit.

In a second alternative the means for detecting if the first clamp means is in the open position of the closed position includes a sensor located on the first clamp member. The sensor may sense the proximity of the first clamp member to the second clamp member.

Preferably the electrofusion clamp includes a locking means for locking first clamp member with respect to the second clamp member such that the first clamp means is locked in a closed position. The locking means may include an electromagnet which preferably acts between the first electrical contact and the second electrical contact. This enables two functions to be combined and possibly a fail safe for not being able to remove the clamp means until the correct amount of cooling time has taken place. In this version the detecting and recording apparatus not only monitors whether the electrical circuit described above has been broken or not and when it is broken but will physically not allow the circuit to be broken until the correct cooling time has taken place. The detecting and recording apparatus will be programmed with the electrofusion weld details, ie the current and time for the current to be passed through the heating windings and the time required for the weld to cool. Once the clamp is in position and the weld begun the electromagnet will be activated and will remain activated for the combined length of time required for the weld and for the cooling of the weld and will not be removable until after that time period. Obviously a fail safe will be provide in case the operation needs to be stopped early and the detecting and recording apparatus will be able to detect and record if the fail safe is activated to record the joint as "failed". Preferably the electrofusion clamp includes a second clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the second clamp means is moveable from a first open or undamped position to a second closed or clamped position. This is useful when two lengths of pipe are being joined together as a pipe length can be held in each of the clamp means with the electrofusion coupling and joint being located and held in between the two clamp means to provide support. In this version it is preferred that the electrofusion clamp includes a means for detecting if the second clamp means is in the open position of the closed position and a means for recording if the second clamp means is in the open position or the closed position.

In one alternative the means for detecting if the second clamp means is in the open position or the closed position includes a first electrical contact located on the first clamp member and a second electrical contact located on the second clamp member such that when the second clamp means is in the open position the electrical contacts are not in contact with each other and when the second clamp means is in the closed position the electrical contacts are in contact with each other. In this case when the first electrical contact is in contact with the second electrical contact an electrical circuit is completed and the means for recording if the second clamp means is in the open position or the closed position records when the electrical circuit is completed and when the electrical circuit is not completed. The first clamp member of the second clamp means may include a first electrical terminal electrically connected to the first electrical contact. This enables in the case of a dual clamp means being provided a circuit to be created either as two separate circuits or as a single circuit. The two separates circuits will both originate from the detecting and recording apparatus which may be either integral with the electrofusion clamp or separate there from the first circuit will be to the first clamp means and the first clamp member thereof via the first electrical terminal to the first electrical contact to the second electrical contact, when the first clamp means is in the closed position, to an second electrical terminal which is electrically connected to the second electrical contact and preferably located within the second clamp member which goes back to the detecting and recording apparatus to complete the circuit. The second circuit will be to the second clamp means and the first clamp member thereof via the first electrical terminal to the first electrical contact to the second electrical contact, when the second clamp means is in the closed position, to an second electrical terminal which is electrically connected to the second electrical contact and preferably located within the second clamp member which goes back to the detecting and recording apparatus to complete the circuit. In the case of the single circuit this requires an electrical connection to be created between the first clamp means and the second clamp means. The single circuit will again originate from the detecting and recording apparatus which may be either integral with the electrofusion clamp or separate there from to the first clamp means and the first clamp member thereof via the first electrical terminal to the first electrical contact to the second electrical contact, when the first clamp means is in the closed position, o the second clamp means via either an internal or external electrical connection to the second electrical contact located in the second clamp member through to the first electrical contact in the first clamp member when the second clamp means is in the closed position and then through to the first electrical terminal and back to the detecting and recording apparatus to complete the circuit. In a second alternative the means for detecting if the second clamp means is in the open position of the closed position includes a sensor located on the first clamp member. The sensor may sense the proximity of the first clamp member to the second clamp member. Preferably the electrofusion clamp includes a locking means for locking first clamp member with respect to the second clamp member such that the second clamp means is locked in a closed position. The locking means may include an electromagnet which preferably acts between the first electrical contact and the second electrical contact. This enables two functions to be combined and possibly a fail safe for not being able to remove the clamp means until the correct amount of cooling time has taken place. In this version the detecting and recording apparatus not only monitors whether the electrical circuit described above has been broken or not and when it is broken but will physically not allow the circuit to be broken until the correct cooling time has taken place. The detecting and recording apparatus will be programmed with the electrofusion weld details, ie the current and time for the current to be passed through the heating windings and the time required for the weld to cool. Once the clamp is in position and the weld begun the electromagnet will be activated and will remain activated for the combined length of time required for the weld and for the cooling of the weld and will not be removable until after that time period. Obviously a fail safe will be provide in case the operation needs to be stopped early and the detecting and recording apparatus will be able to detect and record if the fail safe is activated to record the joint as "failed".

Preferably when the clamp has both a first clamp means and a second clamp means these are connected together. As well as being physically connected together the first and second clamp mean are also preferably electrically connected together, this connection may be via the second electrical connection on the second clamp member of the first clamp means and the second electrical connection on the second clamp member of the second clamp means.

Preferably the first and second clamp members are pivotally connected, alternatively the first and second clamp members may be connected together by a connecting member which the first and/or second clamp members are adapted to move laterally about for example the first and/or second clamp members may slide up and down the connecting member. The electrofusion clamp is preferably generally adapted to hold a first plastics component in a fixed relationship with a second plastics component in use. The electrofusion clamp may be for example an alignment clamp and/or a re-rounding clamp. According to a second aspect of the present invention there is provided an apparatus for detecting and/or recording when an electrofusion clamp is in an open undamped position and/or in a closed clamped position. The apparatus may be integral with or separate from the electrofusion clamp. The apparatus may simply be a computer chip with a memory loaded with a computer program which records the data from the detection means which is located integrally in the electrofusion clamp. In the alternative the apparatus may instead be integral with the electrofusion welding machine which simultaneously records information about the weld process and the cooling time (ie how long the clamp is closed for after the weld process has been completed). The apparatus may also control any electromagnets used to keep the clamp in closed position during the allotted cooling time.

In this alternative the apparatus may include a means for making an external electrical connection between the first electrical terminal located on the first clamp member of the first clamp means and the first electrical terminal^" located on the first clamp member of the second clamp means and also may include an electrofusion welding means. Preferably the electrofusion welding means includes a first means for connecting to a first electrical terminal of a first plastics component and a second means for connecting to a second electrical terminal of the first plastics component in use wherein the first plastics component is to be electrofused to the second plastics component and the first plastics component includes heating windings located between the first electrical terminal and the second electrical terminal, and wherein the electrofusion welding means is adapted in use to pass electrical current into the first electrical terminal through the heating windings and out of the second electrical terminal of the first plastics component. It is also preferred that the apparatus includes a means for recording information from the electrofusion welding means ie the time, date, operator, type and location of weld, current required, voltage required, time of current required, cooling time required and so on. This data collected can then be compared either simultaneously or at a later date with the data which corresponds to a correct weld or a failed weld to determine whether or not the weld has been successful.

According to a third aspect of the present invention there is provided an electrofusion system including an electrofusion clamp an apparatus for detecting and/or recording when an electrofusion clamp is in an open undamped position and/or in a closed clamped position.

According to a fourth aspect of the present invention there is provided a method of detecting whether an electrofusion clamp is in an open position or a closed position including;

a) providing an electrofusion clamp;

b) providing an apparatus for detecting and/or recording when an electrofusion clamp is in an open position or a closed position; c) electrically connecting the electrofusion clamp to the apparatus;

d) analysing the results of the means for detecting and/or recording if the first clamp means is in the open position of the closed position. Essentially in a preferred version the electrofusion clamp, which may have either one or two or more clamp means, is electrically connected to the apparatus for detecting and/or recording when an electrofusion clamp is in an open position or a closed position. This is ideally the same apparatus which is used to pass current to form the electrofusion weld which records information about the electrofusion weld. When only one clamp means is present the apparatus is connected to either side of the clamp such that when the clamp is closed the circuit is completed. When two or more clamp means are present the apparatus is connected to the end clamp means each clamp means being electrically internally connected to each other and each clamp means only completing the circuit through electrical connections in the clamp members when the clamp means are in the closed position. In a particularly preferred version the electrical circuit once completed and connected causes an electromagnet to become activated which only deactivates and allows the clamp to be opened after the allotted time for both the weld and the cooling time has been completed.

According to a fifth aspect of the present invention there is provided an electrofusion clamp including; a first clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the first clamp means is moveable from a first open or undamped position to a second closed or clamped position for clamping a first plastics component in use; and a first scraping means for scraping a surface of the first plastics component being clamped by the first clamp means in use. This is advantageous because is allows for the scraper which is usually in the form of a cutting blade to be stored safely on the electrofusion clamp rather than leading the risk of getting lost or misplaced on site. The integral nature of the scraper is also safer for the people on site as the scraping occurs automatically without any digits or limbs risking being caught in the path of the scraper due to any slips.

Preferably the first clamp means includes a means for rotating the first plastics component in use wherein in use when the first plastics component is rotated a surface of the first plastics material comes into contact with the first scraping means and a layer of plastics material is removed from the surface of the first plastics component. In the alternative the first clamp means includes a means for in use rotating the scraper means about the first plastics material. Preferably the electrofusion clamp includes a second clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the second clamp means is moveable from a first open or undamped position to a second closed or clamped position for clamping a second plastics component in use.

Preferably the electrofusion clamp includes a second scraping means for scraping a surface of the second plastics component being clamped by the second clamp means in use. This allows two pipes for example to be scraped at the same time in the case of a coupling being employed to join two lengths of pipe together.

Preferably the second clamp means includes a means for rotating the second plastics component in use wherein in use when the first plastics component is rotated the surface of the second plastics material comes into contact with the second scraping means and a layer of plastics material is removed from the surface of the second plastics component. In the alternative the second clamp means includes a means for in use rotating the second scraper means about the second plastics material.

According to a sixth aspect of the present invention there is provided an electrofusion clamp including; a first clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the first clamp means is moveable from a first open or undamped position to a second closed or clamped position for clamping a first plastics component in use; a second clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the second clamp means is moveable from a first open or undamped position to a second closed or clamped position for clamping a second plastics component in use; and a hydraulic means for connecting the first clamp means to the second clamp means. Preferably the hydraulic means operates to move the first clamp means relative to the second clamp means.

Brief Description of the Drawings Figure 1 illustrates an electrofusion clamp according to an embodiment of the present invention in an open position;

Figure 2 illustrates an electrofusion clamp according to an embodiment of the present invention in a closed position;

Figure 3a illustrates an electrofusion clamp according to an embodiment of the present invention in-use with a first connection arrangement;

Figure 3b illustrates an electrofusion clamp according to an embodiment of the present invention in-use with a second connection arrangement;

Figure 4 illustrates an electrofusion clamp according to an alternate embodiment of the present invention in-use which is provided with scraper means; Figure 5 illustrates an alternate scraper means:

Figure 6 illustrates a portion of an electrofusion clamp indicating where the scraper means of Figure 5 would be located: Figure 7 illustrates an electrofusion clamp according to an alternate embodiment of the present invention in-use which is provided with a hydraulic means for changing the distance between the first and second clamp means;

Figure 8 illustrates an electrofusion clamp according to an alternate embodiment of the present invention in-use which is provided with a mechanical means for changing the distance between the first and second clamp means;

Figure 9 illustrates an electrofusion clamp according to an alternate embodiment of the present invention in-use which is provided with a hydraulic means for changing the distance between the first and second clamp means and a scraper means; and Figure 10 illustrates an electrofusion clamp according to an alternate embodiment of the present invention in-use which is provided with a mechanical means for changing the distance between the first and second clamp means and a scraper means.

Detailed Description of the Preferred Embodiments

Figure 1 illustrates an embodiment of an electrofusion clamp according to the present invention in an open position. The electrofusion clamp shown generally as 10 has a first clamp means 12 and a second clamp means 14. The first clamp means 12 is connected to the second clamp means 14 with a connecting member 16. The first clamp means 12 and second clamp means 14 are adapted to be able to slide within the connecting member 16 by means of apertures 18, 20 such that the length of the electrofusion clamp 10 and distance between the first clamp means 12 and second clamp means 14 can be readily changed.

The first clamp means 12 has a first clamp member 22 and a second clamp member 24. The first clamp member 22 is pivotally connected to the second clamp member 24 by means of a hinge 26. The first clamp member 22 and second clamp member 24 are both semi-circular such that when they are connected together they form a ring. The internal diameter of the ring corresponds to the external diameter of a pipe to be electrofused. The electrofusion clamp 10 is designed to be used in the electrofusion of two plastic pipe components with an electrofusion coupling. Other forms of clamp may be envisaged to join other components such as a pipe to a chamber wall and this particular construction is not intended to be limiting. The second clamp member 24 is adapted to be slidably attached to the connecting member 16. The first clamp member 22 has a first electrical contact 28. The second clamp member 24 has a second electrical contact 30. When the first clamp member 22 and second clamp member 24 are arranged such that the first clamp means 12 is in the closed, clamping position the first electrical contact 28 contacts the second electrical contact 30, such that electricity can flow therebetween so that the first and second clamp means 22, 24 can clamp tightly around a length of pipe. The first and second electrical contacts 28,30 are spring loaded. The first electrical contact 28 is provided with an internal sensor 32 prior to being electrically connected to a first electrical terminal 34. The internal sensor 32 is provided such that if the wires were connected without passing through the clamp ie short circuiting then this would be recorded as clamp open. The internal sensor 32 may be for example a resistor, and the recordal apparatus will know the resistance and thus the actual current expected back at the recordal apparatus after passing through two such resistors or other means of internal sensor 32 which will not be the same as a straight length of wire. The second electrical contact 28 is electrically connected to the connecting member 16 by means of an internal connecting lead 36. In order to secure in position the first and second clamping members 22, 24 in a closed, clamping position, the first and second clamping members 22, 24 are provided with apertures 38, 40 which locking member 42 is adapted to engage with. The locking member 42 may be a locking nut and bar as shown. In an alternative the first and second clamping member 22, 24 may be held in place with an electromagnet.

The second clamp means 14 has a first clamp member 44 and a second clamp member 46. The first clamp member 44 is pivotally connected to the second clamp member 46 by means of a hinge 48. The first clamp member 44 and second clamp member 46 are both semi-circular such that when they are connected together they form a ring. The internal diameter of the ring corresponds to the external diameter of the pipe to be electrofused. As stated above this construction is not intended to be limiting. The second clamp member 46 is adapted to be slidably attached to the connecting member 16. The first clamp member 44 has a first electrical contact 50. The second clamp member 46 has a second electrical contact 52. When the first clamp member 44 and second clamp member 46 are arranged such that the second clamp means 14 is in the closed, clamping position the first electrical contact so contacts the second electrical contact 52, such that electricity can flow therebetween so that the first and second clamp means 44, 46 can clamp tightly around a length of pipe. The first and second electrical contacts 50, 52 are spring loaded. The first electrical contact 50 is provided with an internal sensor 54 prior to being electrically connected to a first electrical terminal 56. The internal sensor 54 is provided such that if the wires were connected without passing through the clamp ie short circuiting then this would be recorded as clamp open. The internal sensor 54 may be for example a resistor, and the recordal apparatus will know the resistance and thus the actual current expected back at the recordal apparatus after passing through two such resistors or other means of internal sensor 54 which will not be the same as a straight length of wire. The second electrical contact 52 is electrically connected to the connecting member 16 by means of an internal connecting lead 36, which in turn connects to the second electrical contact 30 in the second clamping member 24 of the first clamping means 12. In order to secure in position the first and second clamping members 44, 46 in a closed, clamping position, the first and second clamping members 44, 46 are provided with apertures 58, 60 which locking member 62 is adapted to engage with. The locking member 62 may be a locking nut and bar as shown. In an alternative the first and second clamping member 44, 46 may be held in place with an electromagnet. An optional clamp connection 64 may be provided for when a T-joint is being electrofused rather than a straight length of pipe.

Figure 2 illustrates an embodiment of an electrofusion clamp according to the present invention in a closed position. The same reference signs have been employed as in Figure 1. The electrical terminals 34, 56 are not shown.

Figure 3a illustrates an embodiment of an electrofusion clamp according to the present invention in situ about pipe lengths 66, 68, being electrofused with an electrofusion coupler 70 using an electrofusion welding apparatus 72. The same reference signs have been employed as in Figure 1 and Figure 2.

The electrofusion clamp 10 is clamped with the first clamp means 12 and second clamp means 14 about pipe lengths 66 and 68 respectively. The pipe lengths 66 and 68 are being coupled together with an electrofusion coupler 70. The electrofusion coupler is provided with electrical heating windings on its internal surface which contact the external surfaces of the pipe lengths 66, 68. When electricity is passed into the electrical heating windings by means of electrical terminal connections 74, 76 from the electrofusion welding apparatus 72, the electrical heating windings heat up and melts together the surrounding plastics materials of the coupler 70 and the pipe lengths 66, 68, which when allowed to cool and set forms an electrofusion weld.

In the embodiment shown electricity is also passed from the electrofusion welding apparatus 72 into the first clamp means 12 via the first electrical terminal 34 which then travels through the first electrical contact (not shown) into the second electrical contact (not shown) through the connecting member 16 into the second electrical contact (not shown) to the second clamp means 14 to the first electrical contact (not shown) to the first electrical terminal 56 and back to the electrofusion welding apparatus 72 to complete the circuit. The electrofusion welding apparatus 72 records when the electrical circuit is completed (ie clamp in closed position) and when it is not (ie clamp in open position). This data can then be compared with the length of time that clamp should have been clamping for, which may be the electrofusion time plus cooling time or cooling time only for example, to determine if the join has 'failed'.

Figure 3b illustrates the same embodiment of an electrofusion clamp according to the present invention as shown in Figure 3a above in situ about pipe lengths 66, 68, being electrofused with an electrofusion coupler 70 using an electrofusion welding apparatus 72. The same reference signs have been employed as in Figure 1 and Figure 2. The difference between Figure 3a and Figure 3b is the way that the electrofusion clamp is connected to the electrofusion welding apparatus. In Figure 3a the same connection that connects the electrofusion welding apparatus to the electrofusion coupler is used, whereas in Figure 3b a separate connection is used. Figure 4 illustrates an alternative embodiment of the present invention which includes features which may be used in conjunction with or separately from the embodiment illustrated in Figures 1 to 3 like reference numerals have been used as in Figures 1 to 3 where applicable. The electrofusion clamp 10 is clamped with first clamp means 12 and second clamp means 14 above pipe lengths 66 and 68 respectively. The pipe lengths 66 and 68 are being coupled together with an electrofusion coupler 70. In order to obtain a good electrofusion weld it is necessary to remove the outer surface of the pipe length being electrofused.

Integral first and second scraping means 78, 80 are provided which either rotate about the first and second clamp means 12, 14 or which remain stationary and are pressed against the pipe lengths, the pipe lengths then being rotated. In this embodiment it is preferred that the pipes are rotated.

Figure 5 illustrates an alternate scraping means 88 to that shown in Figure 4 which comprises an electric motor 92 designed to be able to rotate about the bed 90. The scraping means is provided with 4 cutting blades 94, 96, 98, 100. In this embodiment it is preferred that the scraping means is rotated by means of the electric motor 92 rotating about the bed 90. Figure 6 illustrates the location 102 where the scraping means 88 of Figure 5 would be located in the electrofusion clamp. Ideally two scraping means 88 would be provided, one for each clamping means 12, 14. Figure 7 illustrates an alternative embodiment of the present invention which includes features which may be used in conjunction with or separately from the embodiment illustrated in Figures 1 to 3 like reference numerals have been used as in Figures 1 to 3 where applicable. A hydraulic ram 82 may be provided to move the first and second clamping means 12, 14 relative to each other.

Figure 8 illustrates an alternative embodiment of the present invention which includes features which may be used in conjunction with or separately from the embodiment illustrated in Figures 1 to 3 like reference numerals have been used as in Figures 1 to 3 where applicable.

Electric motors 82 and 84 which move about bed 86 may be provided to move the first and second clamping means 12, 14 relative to each other.

Figure 9 illustrates an alternative embodiment of the present invention which includes features which may be used in conjunction with or separately from the embodiment illustrated in Figures 1 to 3 like reference numerals have been used as in Figures 1 to 7 where applicable. In this embodiment the embodiments shown in Figures 4 and 7 have been combined.

Figure 10 illustrates an alternative embodiment of the present invention which includes features which may be used in conjunction with or separately from the embodiment illustrated in Figures 1 to 3 like reference numerals have been used as in Figures 1 to 8 where applicable. In this embodiment the embodiments shown in Figures 4 and 8 have been combined.

The principal of Electro-Fusion is to joint two or more plastic (PE) pipes. This is achieved by inserting the ends of the pipe into a joint (which is termed coupling or collar). This coupling has an integral heating element which when current is passed through it melts the surface of the coupling to the wall of the pipe to form a gas/water tight joint.

It has always been important to record jointing parameters i.e. length of weld time, current, voltage, location, date, time, operator ID etc. This data is stored within the integral memory of the Electro-Fusion Controller and can be downloaded as required.

Two other vital operations for joint integrity are: a) To ensure pipes being jointed have a restraining (alignment)/re-rounding clamp attached at all times within the heating and cooling process. All Electro-Fusion couplings have a pre-determined heating and cooling time which must be strictly adhered to if jointing integrity is to be assured. b) To ensure that the wall of the pipes are scraped before they are inserted into the coupling before being jointed. This scraping process is essential to remove any oxidisation and contamination. Historically, it has not been possible to prove and record data for the cooling process in the form of detecting if the clamps are not fitted, or removed prematurely.

Also historically, it has not been possible to prove and record data for the scraping process in the form of detecting if the pipe ends were scraped before insertion into the coupling.

With the invention of the Electro-Services Limited MultiFuse+ 'Cool Clamp', both these jointing processes can now be verified and recorded. This is an 'intelligent' clamp which incorporates switches/sensors which inform the MultiFuse+ Electro- Fusion Controller if the pipe clamps are removed during the jointing process (this includes heating and cooling times).

The patent includes any form of sensor i.e. electrical, mechanical, hydraulic, electronic, capacitive, resistive, photo-electrical, inductive, or video etc, which enables the MultiFuse+ Electro-Fusion Controller to detect connection and removal of the clamp. The patent also includes any form of scraper i.e. electrical, mechanical, hydraulic or abrasive. These can take the form of blades mounted on a cutting disk moved around the pipe, or a fixed blade which the pipe rotates around. The driving power can be electrical, mechanical or hydraulic. The scraping process and the insertion of the pipe ends into the coupling (clamp closure) are automatically controlled by the MultiFuse+ Electro-Fusion Controller.

Connection can be made to the clamp from the Controller by an independent cable or via the Electro-Fusion output leads.

The clamp is constructed so it acts as a alignment and/or a

re-rounding clamp. The MultiFuse+ Electro-Fusion Controller will automatically sense if the clamp is connected or disconnected and record this data. The clamp has internal sensors which prevent operator override.

The intelligent display on the MutliFuse+ Electro-Fusion Controller informs the operator of clamp status during heating and cooling processes. The cool clamp can also sense the correct pressure of the clamping/re-rounding process enabling this data to be stored within the MultiFuse+ Electro-Fusion Controller.

The MultiFuse+ Cool Clamp can only be used in conjunction with the MultiFuse+ Electro-Fusion Controller and cannot be used with other makes/models produced by other manufacturers.

Claims

1 . An electrofusion clamp including;

a) a first clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the first clamp means is moveable from a first open or undamped position to a second closed or clamped position; and

b) a means for detecting if the first clamp means is in the open position of the closed position.

2. An electrofusion clamp as claimed in Claim 1 including a means for recording if the first clamp means is in the open position or the closed position.

3. An electrofusion clamp as claimed in Claim 1 or Claim 2 wherein the means for detecting if the first clamp means is in the open position or the closed position includes a first electrical contact located on the first clamp member and a second electrical contact located on the second clamp member such that when the first clamp means is in the open position the electrical contacts are not in contact with each other and when the first clamp means is in the closed position the electrical contacts are in contact with each other.

4. An electrofusion clamp as claimed in Claim 3 wherein when the first electrical contact is in contact with the second electrical contact an electrical circuit is completed.

5. An electrofusion clamp as claimed in Claim 4 when dependent upon Claim 2 wherein the means for recording if the first clamp means is in the open position or the closed position records when the electrical circuit is completed and when the electrical circuit is not completed.

6. An electrofusion clamp as claimed in any of claims 3 to 5 wherein the first clamp member of the first clamp means includes a first electrical terminal electrically connected to the first electrical contact.

7. An electrofusion clamp as claimed in Claim 1 or Claim 2 wherein the means for detecting if the first clamp means is in the open position of the closed position includes a sensor located on the first clamp member.

8. An electrofusion clamp as claimed in Claim 7 wherein the sensor senses the proximity of the first clamp member to the second clamp member.

9. An electrofusion clamp as claimed in any preceding claim including a locking means for locking first clamp member with respect to the second clamp member such that the first clamp means is locked in a closed position.

10. An electrofusion clamp as claimed in Claim 9 wherein the locking means includes an electromagnet.

1 1 . An electrofusion clamp as claimed in Claim 10 when dependent upon Claim 3 wherein the electromagnet acts between the first electrical contact and the second electrical contact

12. An electrofusion clamp as claimed in any preceding claim including a second clamp means including a first clamp member and a second clamp member wherein the first clamp member is moveable with respect to the second clamp member such that the second clamp means is moveable from a first open or undamped position to a second closed or clamped position.

13. An electrofusion clamp as claimed in Claim 12 including a means for detecting if the second clamp means is in the open position of the closed position.

14. An electrofusion clamp as claimed in Claim 13 including a means for recording if the second clamp means is in the open position or the closed position.

15. An electrofusion clamp as claimed in Claim 13 or Claim 14 wherein the means for detecting if the second clamp means is in the open position or the closed position includes a first electrical contact located on the first clamp member and a second electrical contact located on the second clamp member such that when the second clamp means is in the open position the electrical contacts are not in contact with each other and when the second clamp means is in the closed position the electrical contacts are in contact with each other.

16. An electrofusion clamp as claimed in Claim 14 wherein when the first electrical contact is in contact with the second electrical contact an electrical circuit is completed.

17. An electrofusion clamp as claimed in Claim 16 when dependent upon Claim 9 wherein the means for recording if the second clamp means is in the open position or the closed position records when the electrical circuit is completed and when the electrical circuit is not completed.

18. An electrofusion clamp as claimed in any of claims 15 to 17 wherein the first clamp member of the second clamp means includes a first electrical terminal electrically connected to the first electrical contact.

19. An electrofusion clamp as claimed in any of claims 12 to 14 wherein the means for detecting if the second clamp means is in the open position of the closed position includes a sensor located on the first clamp member.

20. An electrofusion clamp as claimed in Claim 19 wherein the sensor senses the proximity of the first clamp member to the second clamp member.

21 . An electrofusion clamp as claimed in any of claims 12 to 20 including a locking means for locking first clamp member with respect to the second clamp member such that the second clamp means is locked in a closed position.

22. An electrofusion clamp as claimed in Claim 21 wherein the locking means includes an electromagnet.

23. An electrofusion clamp as claimed in Claim 22 when dependent upon Claim 15 wherein the electromagnet acts between the first electrical contact and the second electrical contact

24. An electrofusion clamp as claimed in any of claim 12 to 23 wherein the first clamp means is connected to the second clamp means.

25. An electrofusion clamp as claimed in Claim 24 wherein the first clamp means is electrically connected to the second clamp means.

26. An electrofusion clamp as claimed in Claim 25 wherein the first clamp means is electrically connected to the second clamp means via the second electrical connection on the second clamp member of the first clamp means and the second electrical connection on the second clamp member of the second clamp means.

27. An electrofusion clamp as claimed in any preceding claim wherein the first and second clamp members are pivotally connected.

28. An electrofusion clamp as claimed in any preceding claim adapted to hold a first plastics component in a fixed relationship with a second plastics component in use.

29. An electrofusion clamp as claimed in any preceding claim being an alignment clamp and/or a re-rounding clamp.

30. An electrofusion clamp a claimed in any preceding claim including a first scraping means for scraping a surface of the first plastics component being clamped by the first clamp means in use.

31 . An electrofusion clamp as claimed in Claim 30 wherein the first clamp means includes a means for rotating the first plastics component or the first scraper means in use wherein in use when the first plastics material comes into contact with the first scraping means a layer of plastics material is removed from the surface of the first plastics component.

32. An electrofusion clamp as claimed in Claim 30 or Claim 31 when dependent upon Claim 12 including a second scraping means for scraping a surface of the second plastics component being clamped by the second clamp means in use.

33. An electrofusion clamp as claimed in Claim 32 wherein the second clamp means includes a means for rotating the second plastics component or the second scraper means in use wherein in use when the second plastics material comes into contact with the second scraping means a layer of plastics material is removed from the surface of the second plastics component.

34. An electrofusion clamp as claimed in Claim 24 including a hydraulic means or electric motor for connecting the first clamp means to the second clamp means.

35. An electrofusion clamp as claimed in Claim 34 wherein the hydraulic means or electric motor operates to move the first clamp means relative to the second clamp means.

36. An electrofusion clamp as substantially herein described with reference to and as illustrated in any of the combination of the accompanying figures.

37. An apparatus for recording when an electrofusion clamp according to any of claims 1 to 36 is in an open undamped position and/or in a closed clamped position.

38. An apparatus as claimed in Claim 37 when dependent upon Claim 6 and Claim 18 including a means for making an external electrical connection between the first electrical terminal located on the first clamp member of the first clamp means and the first electrical terminal^" located on the first clamp member of the second clamp means.

39. An apparatus as claimed in Claim 37 or Claim 38 including an electrofusion welding means.

40. An apparatus as claimed in Claim 39 wherein the electrofusion welding means includes a first means for connecting to a first electrical terminal of a first plastics component and a second means for connecting to a second electrical terminal of the first plastics component in use wherein the first plastics component is to be electrofused to the second plastics component and the first plastics component includes heating windings located between the first electrical terminal and the second electrical terminal, and wherein the electrofusion welding means is adapted in use to pass electrical current into the first electrical terminal through the heating windings and out of the second electrical terminal of the first plastics component.

41 . An apparatus as claimed in Claim 39 or Claim 40 wherein the apparatus includes a means for recording information from the electrofusion welding means.

42. An apparatus as substantially herein described with reference to and as illustrated in any of the combination of the accompanying figures.

43. An electrofusion system including an electrofusion clamp as claimed in any of claims 1 to 36 and an apparatus as claimed in any of claims 37 to 42.

44. An electrofusion system as substantially herein described with reference to and as illustrated in any of the combination of the accompanying figures.

A method of detecting whether an electrofusion clamp is in an open position closed position including;

a) providing an electrofusion clamp as claimed in any of claims 1 to 36; b) providing an apparatus as claimed in any of claims 37 to 42;

c) electrically connecting the electrofusion clamp to the apparatus; d) analysing the results of the means for detecting if the first clamp means is in the open position of the closed position.

46. A method of detecting whether an electrofusion clamp is in an open position or a closed position as substantially herein described with reference to and as illustrated in any of the combination of the accompanying figures.