Patent Description:
Plastic piping is installed underground and/or above ground to transport liquid, air, gas, waste, etc. to or from home or business. These pipes have a need for many connection branches which may need to be installed in a variation of sizes and angles. Whether the branch is tapping onto an existing line or a newly installed pipe, there is a common need to be able to install these connections within a confined space (excavation, vault, etc). In addition there is a need for a process to be able to install branch connections at variable angles to influence the performance of the piping system or to limit the complexity of the connection.

<CIT> describes a method for mirror welding thermoplastic pipes and fittings using atmospheric pressure. Atmospheric pressure is used for the compression of melted surfaces.

Similarly, <CIT> describes a mirror welding process for joining together thermoplastic material pipe sections, end to end. In the process, each connector end of the pipe is heated to a temperature at least equal to the processing temperature of the thermoplastic material using a mirror welding machine having two heating plates. These softened connector ends of the two pipe sections are pressed together to form a bond and the bond region is cooled. An air-tight seal is formed by pressing a closure part against the opposite end of the pipe section to the heating plate forming a sealed cavity and then applying an under pressure inside the cavity to assist clamping of the pipe section against the heating plate.

Accordingly, there is a need in the art for a method and apparatus to facilitate joining first and second pipes.

A method for joining pipes and an apparatus for facilitating the same are disclosed herein. The apparatus may include a plate for melting mating surfaces of first and second pipes, or in other words, raising its temperature above its softening temperature. The apparatus may also include a cap with a vacuum for generating a negative pressure within the first and/or second pipes to push the first and second pipes together and also to hold the first and second pipes against the plate. The mating surfaces on the first and second pipes are initially melted. Once the mating surfaces have reached its softening temperature, the plate is removed from between the first and second pipes. The mating surfaces are connected to each other (i.e., placed in contact with each other). The cap is placed over one of the first and second pipes and the vacuum activated in order to create a negative pressure within the pipe. The negative pressure pushes the first and second pipes towards each other. The operator allows the first and second pipes to settle upon each other. This means that the angle between the first and second pipes may be slightly different from the intended angle in order that the pressure between the first and second pipes can be equalized about a periphery of the distal end of the first pipe. This creates an especially strong joint.

Additionally, by using a vacuum to create the negative pressure and force the first and second pipes together, the user need not apply hand pressure which could be inconsistent as well as awkward when the first and second pipes are skewed to each other or when the first and second pipes are joined to each other end to end at a skewed angle.

More particularly, in an aspect, a method of forming a liquid tight seal between a distal end of a first pipe and a second pipe is disclosed. The method may comprise the steps of heating the distal end of the first pipe and the second pipe with a heater until the distal end(s) of the first pipe and the second pipe have reached a softening temperature; contacting the distal end of the first pipe to the second pipe; creating a negative pressure within a cavity of the first pipe after the contacting step so that the distal end of the first pipe is pushed into the second pipe; and applying
even pressure about the circumference of the distal end of the first pipe onto the second pipe.

The heating step may be performed until at least <NUM> (<NUM>/<NUM> inch) and more preferably <NUM> (½ inch) (depending on the size and type of material) of the distal end of the first pipe has reached the softening temperature of a material of the pipe.

The heating step may be performed with a plate having opposed first and second sides sized and configured to mate with the distal end of the first pipe and the exterior surface or distal end of the second pipe. The first side may have a convex configuration. The second side may have a concave configuration. Alternatively, the first and second sides may be flat.

The method may further comprise the step of forming a vacuum with an edge of a cup to the exterior surface of the second pipe.

The forming the vacuum step may include the step of capping an opposed distal end of the first pipe with a cap which is in fluid communication with a vacuum device for creating negative pressure.

The applying step may include the step of allowing an angular relationship between the first pipe and the second pipe to change as negative pressure is applied to the cavity of the first pipe, and the distal end of the first pipe is pushed into the second pipe.

The method may further comprise the step of creating the negative pressure within the cavity of the first pipe during the heating step so that the negative pressure created in the cavity of the first pipe is sufficient to hold the first side of the plate of the heater onto the distal end of the first pipe.

The plate of the heater may have a through hole so that the negative pressure created in the cavity of the first pipe is applied between the plate and the second pipe to hold the plate onto the second pipe. The through hole may also have a fitting that can be connected to a hose or line that provides negative pressure to the space between the plate and the second pipe to hold the plate onto the second pipe initially while raising the temperature of the second pipe to its softening temperature. This may be accomplished without the first pipe attached to the heater/plate. After a certain depth of material of the second pipe has been raised to an elevated temperature below its softening temperature, the vacuum line is removed from the fitting and the first pipe is placed on the heater/plate. Vacuum is established in the cavity of the first pipe and the vacuum is communicated to the space between the plate and the second pipe through the through hole or fitting so that the heater can continue to raise a depth of the surfaces of the first and second pipes to its softening temperature.

In the method, the distal end of the first pipe may be attached to an exterior surface of the second pipe. The distal end of the first pipe may be attached to a distal end of the second pipe. Also, the vacuum may be created by capping an opposed distal end of the second pipe.

In another aspect, a pipe attaching machine for forming a liquid tight seal between a distal end of a first pipe and a second pipe is disclosed. The pipe attaching machine may comprise a heater, a cap and a vacuum. The heater may have a plate and a handle. The plate may have opposed first and second sides sized and configured to mate with the distal end of the first pipe and the second pipe. The plate may be operative to provide heat to the distal end of the first pipe and the second pipe for raising its temperature to a softening temperature of the first and second pipes. The handle may be attached to the plate. The handle may be insulated from the plate so that the handle can be gripped by a person to manipulate the heater plate even when the plate is heated. The cap may be sized and configured to provide a seal with an opposed distal end of the first pipe. The vacuum may be operative to create a negative pressure. The vacuum may be in fluid communication with the cap to create negative pressure within a cavity of the first pipe when the cap is mounted to the opposed distal end of the first pipe to hold the first pipe to the heater when heating (i.e., melting) the distal end of the first pipe and also to hold the distal end against the exterior surface of the second pipe when attaching the distal end of the first pipe to the second pipe.

The plate may have a through hole so that negative pressure created in the cavity of the first pipe may be applied between the plate and the second pipe to hold the plate to the second pipe.

The first side of the plate may have a convex configuration sized and be configured to mate with the distal end of the first pipe. The second side of the plate may have a concave configuration sized and configured to mate with an exterior surface of the second pipe.

The plate may also have a cup disposed in the second side. An edge of the cup may be sized and configured to contact the exterior surface of the second pipe before the concave configured second side of the plate to more quickly form a seal to create a negative pressure between the second side of the plate and the exterior surface of the second pipe. Alternatively, in lieu of the cup disposed on the second side of the plate, the seal may be established by contact with a gasket or softening plastic cup or ring.

In an alternate embodiment, the first side of the plate may be flat and be sized and configured to mate with the distal end of the first pipe. Also, the second side of the plate may be flat and be sized and configured to mate with a distal end of the second pipe.

In another aspect, a method for expediting fusion of a distal end of a first pipe to a contact surface of a second pipe is disclosed. The method may comprise the steps of cooling a distal end portion of the first pipe and/or a contact patch portion of the second pipe below its normal temperature; heating the distal end of the first pipe and/or the contact surface of the second pipe so that a portion less than the distal end portion and/or less than the contact patch portion of the second pipe is heated to a softening temperature of a material of the first pipe and/or second pipe; pushing the distal end of the first pipe onto the contact surface of the second pipe; and directing heat away from the distal end of the first pipe and/or the contact patch of the second pipe since less than the distal end portion of the first pipe and/or less than the contact patch portion of the second pipe was heated and the entire distal end portion of the first pipe and the entire contact patch portion was cooled below its normal temperature.

The contact patch may be a distal end of the second pipe. The contact patch may be an exterior surface of the second pipe.

These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:.

Referring now to the drawings, a method and apparatus is disclosed for joining a branch pipe <NUM> to a main pipe <NUM> at a skewed angle <NUM> so that gas, fluid and other solid materials can flow through the branch pipe <NUM> in the direction of arrow <NUM> to flow with gas, fluid and other solid material through the main pipe <NUM> in the direction of arrow <NUM>.

A connection between a distal end <NUM> of the branch pipe <NUM> and an exterior surface <NUM> of the main pipe <NUM> is referred to as a joint <NUM>. The distal end <NUM> of the branch pipe <NUM> and the mating portion of the exterior surface <NUM> of the main pipe <NUM> are heated to a softening temperature then pushed together to form a chemical bond and join the branch pipe <NUM> to the main pipe <NUM>. The periphery of the distal end <NUM> when pushed into the exterior surface <NUM> applies a consistent pressure to the exterior surface <NUM> of the main pipe <NUM> to create a strong connection between the distal end <NUM> of the branch pipe <NUM> and the mating portion of the exterior surface <NUM> of the main pipe <NUM>. To push the distal end <NUM> of the branch pipe <NUM> into the exterior surface <NUM> of the main pipe <NUM> with such consistent pressure, an opposed distal end <NUM> of the branch pipe <NUM> is fitted with a cap <NUM> that has a vacuum <NUM> operative to create a vacuum <NUM> within the branch pipe <NUM>. Once the vacuum <NUM> is turned on, negative pressure is created within the cavity <NUM> of the branch pipe <NUM>. The negative pressure pushes the distal end <NUM> of the branch pipe <NUM> into the exterior surface <NUM> of the main pipe <NUM>. The branch pipe <NUM> is allowed to settle on the main pipe <NUM> so that the angle <NUM> may be different as intended if necessary. The settling insures that the pressure about the periphery of the distal end <NUM> on the exterior surface <NUM> of the main pipe <NUM> is consistent about the entire periphery of the distal end <NUM>.

Referring now to <FIG>, a method of attaching the branch pipe <NUM> to the main pipe <NUM> is shown. The steps of the method shown in <FIG> will be explained in conjunction with <FIG>. To attach the branch pipe <NUM> to the main pipe <NUM>, the distal end <NUM> of the branch pipe <NUM> may be preformed or ground down to mate with the mating portion of the exterior surface <NUM> of the main pipe <NUM> are heated to their softening temperatures. These softening temperatures of the pipes <NUM>, <NUM> vary depending on the material from which the pipes <NUM>, <NUM> are fabricated. By way of example and not limitation, common pipes <NUM>, <NUM> are fabricated from high density polyethylene (HDPE), low density polyethylene (LDPE), polyvinyl chloride (PVC), or polypropelene. For purposes of illustration herein, pipes <NUM>, <NUM> are fabricated from HDPE material. In this regard, the softening temperature for pipes <NUM>, <NUM> which are fabricated from HDPE material is about <NUM> degrees Fahrenheit to <NUM> degrees Fahrenheit.

As discussed above, the distal end <NUM> of the branch pipe <NUM> may be preformed or ground down to mate with the exterior surface of the main pipe <NUM>. If the distal end <NUM> of the branch pipe <NUM> is preformed, then the distal end <NUM> of the branch pipe <NUM> may be formed with a lip that protrudes outward. The lip may protrude outward a small distance so that the pressure between the lip and the exterior surface of the main pipe is equal about the periphery of the distal end of the branch pipe. When the distal end <NUM> of the branch pipe <NUM> is ground down to the shape of the exterior surface of the main pipe, then it is only the thickness of the branch pipe <NUM> that is fused to the exterior surface of the main pipe. Moreover, when the distal end <NUM> of the branch pipe <NUM> is ground down, then no special pipes are needed to make the connection. Standard straight pipes are used and modified on site.

In heating the distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM>, the exterior surface <NUM> of the main pipe <NUM> is melted <NUM>. Moreover, the distal end <NUM> otherwise known as the saddle end of the branch pipe <NUM> is melted <NUM>. The distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM> are melted with a plate <NUM>. The plate <NUM> has a first side <NUM> having a convex configuration. The plate <NUM> also has a second side <NUM> having a concave configuration. The concavity of the second side <NUM> of the plate <NUM> approximates a curvature of the pipe <NUM> so that upon contact of the second side <NUM> of the plate <NUM>, the heat emanating from the second side <NUM> of the plate <NUM> can melt <NUM> the exterior surface <NUM> of the main pipe <NUM>. Similarly, the convex configuration of the first side <NUM> mirrors the concavity of the second side <NUM> so that the first side <NUM> can melt <NUM> the distal end <NUM> of the branch pipe <NUM>. Prior to melting, the end portion of the branch pipe <NUM> may be cut or formed so that the shape of the distal end <NUM> closely approximates the shape of the exterior surface <NUM> of the main pipe <NUM> to which the branch pipe <NUM> connects.

To hold the plate <NUM> against the exterior surface <NUM> of the main pipe <NUM> and the distal end <NUM> of the branch pipe <NUM>, a negative pressure <NUM> can be created within the internal cavity of the branch pipe <NUM> with vacuum <NUM>. Additionally, such negative pressure may also be communicated to cavity <NUM> (see <FIG>) through hole <NUM> of the plate. It is also contemplated that the through hole may be fitted with a fitting sized and configured to receive a vacuum line. Initially, the vacuum line may be connected to the fitting of the plate. The vacuum line provides negative pressure between the plate and the main pipe to hold the heater on the main pipe while raising the temperature of the main pipe toward its softening temperature. This is accomplished without the branch pipe attached to the heater. After a period of time before the main pipe reaches the softening temperature, the vacuum line is removed and the branch pipe is attached to the heater/plate <NUM>. A vacuum created in a cavity of the branch pipe is communicated between the plate and the main pipe through the fitting on the plate. The negative pressure within the internal cavity of the branch pipe <NUM> and the cavity <NUM> between the plate <NUM> and the main pipe <NUM> continues to push the second side <NUM> of the plate <NUM> against exterior surface <NUM> of the main pipe <NUM> as well as pushes the distal end <NUM> of the branch pipe <NUM> against the first side <NUM> of the plate <NUM>. The heat from the plate <NUM> is communicated to the exterior surface <NUM> of the main pipe <NUM> and the distal end <NUM> of the branch pipe <NUM>. About <NUM> (<NUM>/<NUM> of an inch) of the distal end <NUM> of the branch pipe <NUM> is raised to a softening temperature of the pipe <NUM>. Additionally, a depth of about <NUM> (<NUM>/<NUM> of an inch) of the exterior surface <NUM> of the main pipe <NUM> is raised to the softening temperature of the pipe <NUM>. In this manner, when the distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM> are directly attached to each other, the respective materials can form a chemical bond therebetween.

When the exterior surface <NUM> of the main pipe <NUM> and the distal end <NUM> of the branch pipe <NUM> is sufficiently heated as described above, the negative pressure within the internal cavity of the branch pipe <NUM> and the cavity <NUM> is removed so that the plate <NUM> can be removed <NUM> (see <FIG> and <FIG>) from between the branch pipe <NUM> and the main pipe <NUM>. Immediately thereafter, the distal end <NUM> of the branch pipe <NUM> is placed in contact <NUM> (see <FIG> and <FIG>) with the exterior surface of the main pipe. The vacuum <NUM> is turned on again in order to create <NUM> negative pressure within the internal cavity of the branch pipe <NUM>. As you will note from <FIG>, no through hole is formed in the exterior surface <NUM> of the main pipe <NUM> so that the negative pressure in the internal cavity of the branch pipe <NUM> pushes the distal end <NUM> of the branch pipe <NUM> into the exterior surface <NUM> of the main pipe <NUM>. The periphery of the distal end <NUM> of the branch pipe <NUM> may not match perfectly with the exterior surface <NUM> of the main pipe <NUM>. In this regard, as the negative pressure pushes the branch pipe <NUM> into the main pipe <NUM>, such mismatch may cause the branch pipe <NUM> to shift <NUM> from its original intended angle. By way of example and not limitation, the original intended skew angle <NUM> may be <NUM> degrees. However, due to the mismatch between the concavity formed on the distal end <NUM> of the branch pipe <NUM> and the degree of the convex configuration of the exterior surface <NUM> of the main pipe <NUM>, the skew angle <NUM> may be <NUM> degrees ± <NUM> degrees and more preferably ± <NUM> degrees after connection of the branch pipe <NUM> to the main pipe <NUM>. Such shifting equalizes the pressure about the entire periphery of the distal end <NUM> so that the melted connection between the distal end <NUM> and the exterior surface <NUM> of the main pipe <NUM> has a consistent strength about the entire periphery of the distal end <NUM> of the branch pipe <NUM>. As can be seen from <FIG>, the distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM> form a bead completely about the distal end <NUM> of the branch pipe <NUM>. The connection is a liquid and airtight seal produced with even pressure about the entire periphery of the distal end <NUM> against the exterior surface <NUM> of the main pipe <NUM>.

Referring now to <FIG>, the cap <NUM>, as discussed above, may be in fluid communication with vacuum <NUM> so that the vacuum <NUM> can create a negative pressure within the internal cavity of the branch pipe <NUM>. The cap <NUM> is shown as being disposed over an opposed distal end portion <NUM> to form an airtight seal therewith. The cap <NUM> may have a butterfly valve <NUM> and a bleed valve <NUM>. The butterfly valve <NUM> has an on position and an off position. In the off position, when the vacuum <NUM> is activated, no negative pressure is created within the internal cavity of the branch pipe <NUM>. Also, there is no fluid communication between the vacuum <NUM> and the internal cavity of the branch pipe <NUM>. In the on position, as shown in <FIG>, the vacuum <NUM>, when the vacuum <NUM> is activated, negative pressure is created within the internal cavity of the branch pipe <NUM>. Fluid communication is established between the vacuum <NUM> and the internal cavity of the branch pipe <NUM>. The butterfly valve <NUM> is traversed to the on position after holding the branch pipe <NUM> against the plate <NUM> and the plate <NUM> against the main pipe <NUM> in order to melt <NUM> the distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM>. The butterfly valve <NUM> may be traversed to the off position to allow the heat to soak through the material. The butterfly valve <NUM> is also traversed to the on position when the plate <NUM> is removed from between the branch pipe <NUM>, and the main pipe <NUM> and the distal end <NUM> of the branch pipe <NUM> is placed in contact with and pushed against exterior surface <NUM> of the main pipe <NUM>.

The bleed valve <NUM> remains closed when the vacuum <NUM> is activated and the butterfly valve <NUM> is traversed to the on position. The bleed valve <NUM> is opened in order to equalize the pressure in the internal cavity of the branch pipe <NUM> and the atmosphere. In this manner, the plate <NUM> can be removed from between the branch pipe <NUM> and the main pipe <NUM>. More particularly, after the plate <NUM> has sufficiently melted <NUM> the distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM>, the vacuum <NUM> may be deactivated and/or the butterfly valve <NUM> may be traversed to the closed position. The bleed valve <NUM> may be opened so that air is introduced into the internal cavity of the branch pipe <NUM> to equalize the pressure within the internal cavity of the branch pipe <NUM> to the atmosphere. Additionally, the pressure within the cavity <NUM> between the plate <NUM> and the main pipe <NUM> is also equalized to the atmospheric pressure. Now the branch pipe <NUM> may be removed from the plate <NUM> and the plate <NUM> may be removed from the main pipe <NUM>. The bleed valve <NUM> may be placed downstream of the butterfly valve <NUM> and be disposed between the cap <NUM> and the butterfly valve <NUM>.

The vacuum <NUM> and the cap <NUM> may be in fluid communication with each other by flex line <NUM>. The flex line <NUM> does not collapse in the presence of negative pressure. The cap <NUM> is shown as being attached over the opposed distal end portion <NUM> of the branch pipe <NUM>. However, other configurations of the cap <NUM> are also possible. By way of example and not limitation, the cap <NUM> may be a flange that mates with the opposed distal end of the opposed distal end portion <NUM> of the branch pipe <NUM> and a protrusion that is sized and configured to an inner periphery of the branch pipe <NUM>. The cap <NUM> regardless of whether the cap <NUM> is placed over the opposed distal end portion <NUM> of the branch pipe <NUM> or placed within may be fabricated from a generally flexible material and be somewhat conformable so that the cap <NUM> may conform to the opposed distal end portion <NUM> of the branch pipe <NUM> to form a fluid tight seal between the cap <NUM> and the branch pipe <NUM>.

Referring now the <FIG>, <FIG>, the plate <NUM> defines the first side <NUM> and the second side <NUM>. The first and second sides <NUM>, <NUM> of the plate <NUM> preferably match the configuration of the exterior surface <NUM> of the main pipe <NUM>. Although the apparatus and method described herein relates to the joining of a distal end <NUM> of the branch pipe <NUM> to a round or circular main pipe <NUM>, the apparatus and method described herein may be used to join a branch pipe <NUM> to a main pipe <NUM> having other configurations such as oval, rectangular, square, etc. The apparatus and method described herein is beneficial in joining the branch pipe <NUM> to the main pipe <NUM> at a skewed angle <NUM> since it is difficult to push the branch pipe <NUM> into the main pipe <NUM> by hand when the angle is skewed. The vacuum <NUM> creates negative pressure to hold the branch pipe <NUM>, plate <NUM> and the main pipe <NUM> together during melting as well as the branch pipe <NUM> and the main pipe <NUM> together during joining. It is also contemplated that the branch pipe <NUM> may also be attached to the main pipe <NUM> at a right angle.

As discussed above, the second surface <NUM> of the plate <NUM> is concave. The concavity of the second surface <NUM> is supposed to match the roundness of the second pipe <NUM>. Unfortunately, the pipe <NUM> may sometimes not be truly round thereby causing an imperfect match between the second side <NUM> of the plate <NUM> and the exterior surface <NUM> of the second pipe <NUM>. As shown in <FIG>, in this example, the outer boundaries have a greater gap <NUM> compared to the inner boundaries as referenced by gap <NUM>, or vice versa. Due to the variance, it may take a significantly longer period of time in order to establish a seal between the second side <NUM> of the plate <NUM> and the exterior surface <NUM> of the second pipe <NUM>. Accordingly, the second side <NUM> may be retrofitted with a cup <NUM> having a small diameter <NUM>. The small diameter cup <NUM> due to its smaller diameter or size more quickly forms the seal with the exterior surface <NUM> of the second pipe <NUM>. The cup <NUM> may be heated and capable of penetrating the exterior surface <NUM> of the second pipe <NUM> faster. As such, the user may initially push the cup <NUM> into the exterior surface <NUM> of the second pipe <NUM> for a short period of time before a seal between the cup <NUM> and exterior surface <NUM> is formed. Once the seal is formed, negative pressure is communicated through the through hole <NUM> into the cavity <NUM> to continue pushing the second side <NUM> of the plate <NUM> toward the exterior surface <NUM> of the second pipe <NUM>. The through hole <NUM> may be fitted with a fitting that can receive a vacuum line. Also, the seal with the main pipe can be established through other means other than a cup in the plate. For example, a gasket may be disposed between the plate and the exterior surface of the main pipe or a cup may be formed in the exterior surface of the main pipe.

Referring now to <FIG>, after the distal end <NUM> of the first pipe <NUM> is attached to the exterior surface <NUM> of the second pipe <NUM>, a drillbit <NUM> may be inserted into the cavity of the first pipe <NUM>. The drillbit <NUM> is rotated with the drill <NUM> and used to generate a hole through the exterior surface <NUM> of the second pipe <NUM>. The hole <NUM> provides fluid communication between the first and second pipes <NUM>, <NUM>. Moreover, the outer diameter of the drillbit <NUM> closely approximates the inner diameter of the first pipe <NUM>. After the hole <NUM> is formed by the drillbit <NUM>, the interior surfaces of the joint between the first and second pipes <NUM>, <NUM> are filed or sanded down so that no sharp edges exist therebetween pipes <NUM>, <NUM> so that the fluid and solid materials flowing through the first pipe <NUM> into the second pipe <NUM> are not hindered.

Furthermore, as shown in <FIG>, it is also contemplated that the apparatus and method may be used to join a distal end <NUM> of a first pipe <NUM> to a distal end <NUM> of a second pipe. In this regard, the first and second sides <NUM>, <NUM> of the plate <NUM> may be flat. The opposed distal end <NUM> of the second pipe may be sealed off to provide for a liquid tight environment within the cavity of the second pipe <NUM>. When the plate <NUM> is disposed between the distal ends <NUM>, <NUM> of the first and second pipes <NUM>, <NUM> and the cap <NUM> is placed on the opposed distal end portion of the first pipe <NUM> with the vacuum <NUM> activated, negative pressure is created within the cavity of the first pipe <NUM> and such negative pressure is also communicated to the cavity of the second pipe <NUM> to push the first and second pipes together on the plate <NUM>.

The plate <NUM> has a through hole <NUM> which communicates the negative pressure from one side of the plate <NUM> to the other side of the plate <NUM>. In particular, the negative pressure created within the cavity of the branch pipe <NUM> is communicated to the cavity <NUM> (see <FIG>) on the second side of the plate <NUM>. Additionally, the negative pressure created within the first pipe is created within the internal cavity of the second pipe via the through hole <NUM>.

The first and second sides <NUM>, <NUM> may have a texture formed thereon. As such, when the first and second sides <NUM>, <NUM> of the plate <NUM> are placed on the distal end <NUM> of the branch pipe and the exterior surface <NUM> of the main pipe <NUM>, no negative pressure is created within the internal cavity of the branch pipe <NUM> or the cavity <NUM> between the plate <NUM> and the main pipe <NUM>. The textured form allows for the transfer of air that prevents the formation of a liquid tight seal. Instead, the user may need to initially push the branch pipe <NUM> against the plate <NUM> and the main pipe <NUM> by hand until the heat from the first and second sides <NUM>, <NUM> of the plate <NUM> melts the distal end <NUM> of the branch pipe <NUM> and the exterior surface <NUM> of the main pipe <NUM> to form a liquid tight seal therebetween.

The plate <NUM> may also be attached to a handle <NUM> to aid in removing the plate <NUM> from between the branch pipe <NUM> and the main pipe <NUM>. The handle <NUM> is insulated so that the user can grip the handle <NUM> with a light glove or a bare hand.

Referring now to <FIG>, a second embodiment of a method and apparatus for joining first and second pipes <NUM>, <NUM> is disclosed. The apparatus may include a sleeve <NUM> that is sized and configured to wrap around both the internal surface <NUM> and the exterior surface <NUM> of the pipe <NUM>, <NUM>. The sleeve <NUM> may be connected to a cooling unit <NUM> which actively cools down the sleeve <NUM>. Cold water may flow through the sleeve <NUM>. Alternatively, the sleeve may be a thermoelectric cooler. When the sleeve <NUM> is placed over the distal end portion <NUM> of the pipes <NUM>, <NUM>, the sleeve <NUM> is operative to reduce the temperature of the distal end portion <NUM>. By reducing the temperature of the distal end portion <NUM> of the pipe <NUM>, <NUM>, heat introduced into the distal end <NUM> of the pipe <NUM>, <NUM> can be more quickly removed therefrom to lower the temperature below its softening temperature so that the operator need not wait as long for the heated portions of the pipes <NUM>, <NUM> to cool to form the joint <NUM>.

When the plate <NUM> heats up the distal end <NUM> of the pipes <NUM>, <NUM> in order to raise its temperature above the softening temperature of the pipes <NUM>, <NUM>, the heat penetrates the distal end <NUM> of the pipes <NUM>, <NUM> a distance <NUM> that is less than the distal end portion <NUM>. As such, a smaller portion <NUM> is raised to the softening temperature of the material of the pipes <NUM>, <NUM>. During operation, the sleeve <NUM> cools down the entire distal end portion <NUM> of the pipes <NUM>, <NUM>. In contrast, the plate <NUM> raises the temperature of the distal ends <NUM> of the pipes <NUM>, <NUM> above the softening temperature of the material of the pipes <NUM>, <NUM>. In other words, the portions <NUM> of the pipes <NUM>, <NUM> are raised to the softening temperature.

In other words, the portions <NUM> of the pipes <NUM>, <NUM> are raised to the softening temperature while the remaining portion <NUM> remains at a temperature lower than the softening temperature. After the plate <NUM> is removed and the distal ends <NUM> of the pipes <NUM>, <NUM> are pushed together, the heat from the portions <NUM> is drawn into the remaining portion <NUM> to accelerate cool down of the smaller portions <NUM> of the pipes <NUM>, <NUM>. In order to assist in the process, the various aspects and method steps described in relation to the vacuum <NUM> and the cap <NUM> may be used in joining the distal ends <NUM> of the first and second pipes <NUM>, <NUM>.

Claim 1:
A method of forming a liquid tight seal between a distal end (<NUM>) of a first pipe (<NUM>) and a second pipe (<NUM>), the method comprising the steps of:
heating the distal end (<NUM>) of the first pipe (<NUM>) and the second pipe (<NUM>) with a heater until the distal end (<NUM>) of the first pipe (<NUM>) and the second pipe (<NUM>) have reached a softening temperature;
contacting the distal end (<NUM>) of the first pipe to an exterior surface (<NUM>) of the second pipe (<NUM>);
characterised by creating a negative pressure (<NUM>) within an internal cavity of the first pipe (<NUM>) after the contacting step so that the distal end (<NUM>) of the first pipe (<NUM>) is pushed into the exterior surface (<NUM>) of the second pipe (<NUM>);
applying even pressure about the circumference of the distal end (<NUM>) of the first pipe onto the second pipe (<NUM>),
after the distal end (<NUM>) of the first pipe (<NUM>) is attached to the exterior surface (<NUM>) of the second pipe (<NUM>), drilling a hole (<NUM>) through the exterior surface (<NUM>) of the second pipe (<NUM>) by inserting a drill bit (<NUM>) into the first pipe and rotating the drill bit, to provide fluid communication between the first and second pipes (<NUM>, <NUM>).