A method for forming a connection between two tubular sections having a polymeric outer surface jacket, using electrofusion to fusion bond a casing of similar, non-crosslinked polymer to the outer surface of the tubular sections.

A clamping ring that presses an end of a pipe against a connecting piece by back shrinkage. The clamping ring comprises a body comprising a plastic material having memory properties. The body has a first end to be positioned at a distance from the end of the pipe and a second end to be positioned close to the end of the pipe. The body of the clamping ring has a first position at the first end or at the distance from the first end having a first radial wall thickness. The body of the clamping ring has at least one second position between the first position and the second end such that the body of the clamping ring has a second radial wall thickness at the second position. The second radial wall thickness is smaller than the first radial wall thickness.

A clamping ring that presses an end of a pipe against a connecting piece by back shrinkage. The clamping ring comprises a body comprising a plastic material having memory properties. The body has a first end to be positioned at a distance from the end of the pipe and a second end to be positioned close to the end of the pipe. The body of the clamping ring has a first position at the first end or at the distance from the first end having a first radial wall thickness. The body of the clamping ring has at least one second position between the first position and the second end such that the body of the clamping ring has a second radial wall thickness at the second position. The second radial wall thickness is smaller than the first radial wall thickness.

A compression collar is manufactured for use in reinforcing an interference fit between an end of a pipe and a fitting. A precursor form is injection molded using a cold-expansion material. The precursor form has a tubular body with an initially closed axial end and a bore that is initially blind formed in the other axial end. Material is removed from the initially closed axial end of the tubular body of the precursor form to form an opening in the initially closed axial end that connects to the bore thereby forming the compression collar. The opening has an inner periphery with a profile in axial cross section that is different than any profile in axial cross section of an inner periphery of the bore. The collar formed may lack knitlines and may include tabs formed during the removal step which help to position the collar on a pipe.

A compression collar is manufactured for use in reinforcing an interference fit between an end of a pipe and a fitting. A precursor form is injection molded using a cold-expansion material. The precursor form has a tubular body with an initially closed axial end and a bore that is initially blind formed in the other axial end. Material is removed from the initially closed axial end of the tubular body of the precursor form to form an opening in the initially closed axial end that connects to the bore thereby forming the compression collar. The opening has an inner periphery with a profile in axial cross section that is different than any profile in axial cross section of an inner periphery of the bore. The collar formed may lack knitlines and may include tabs formed during the removal step which help to position the collar on a pipe.

Described is a peelable heat shrink tube composed of a fluororesin and having a determination coefficient calculated from [Equation 1] below using an elastic modulus ratio (%) of more than 0, but 0.90 or less: $\begin{array}{cc}\mathrm{Determination}\mathrm{coefficient}={\left(\mathrm{correlation}\mathrm{coefficient}\right)}^2={\left[\frac{\left(\mathrm{covariance}\right)}{\left(\mathrm{standard}\mathrm{deviation}\mathrm{of}X\right)\left(\mathrm{standard}\mathrm{deviation}\mathrm{of}Y\right)}\right]}^2& \left[\mathrm{Equation}1\right]\end{array}$
where X, Y and covariance represent the following: X: Proportion of the position of each point, where the elastic modulus was measured, from the interior of the tube Y: Elastic modulus ratio in each region Covariance: Average of the product of deviations of X and Y.

Described is a peelable heat shrink tube composed of a fluororesin and having a determination coefficient calculated from [Equation 1] below using an elastic modulus ratio (%) of more than 0, but 0.90 or less: $\begin{array}{cc}\mathrm{Determination}\mathrm{coefficient}={\left(\mathrm{correlation}\mathrm{coefficient}\right)}^2={\left[\frac{\left(\mathrm{covariance}\right)}{\left(\mathrm{standard}\mathrm{deviation}\mathrm{of}X\right)\left(\mathrm{standard}\mathrm{deviation}\mathrm{of}Y\right)}\right]}^2& \left[\mathrm{Equation}1\right]\end{array}$
where X, Y and covariance represent the following: X: Proportion of the position of each point, where the elastic modulus was measured, from the interior of the tube Y: Elastic modulus ratio in each region Covariance: Average of the product of deviations of X and Y.

A fastener free joining system includes a first tubular shell component having a first plurality of teeth defined in a first free end, each tooth extending along a respective tooth axis oblique to an axis of the first component by an angle . The first plurality of teeth is configured to engage with a plurality of complimentary teeth defined in a second free end of a second tubular shell component, such that, when engaged, the first plurality of teeth is configured to remain engaged with the plurality of complimentary teeth under axial load.

A pipe fitting (100) includes a tubular connecting part (101); the tubular connecting part being configured to be inserted into an expanded pipe end section (111) of a pipe (110) having a first circumferential intact sealing region (113) on the inner surface (112) of the pipe end section (111); the tubular connecting part comprising a first radially outwards extending circumferential sealing barb (105) positioned for engaging, when in use, with the first circumferential intact sealing region during shrinkage of the pipe end section for forming a sealing between the pipe fitting and the pipe.

A pipe fitting (100) includes a tubular connecting part (101); the tubular connecting part being configured to be inserted into an expanded pipe end section (111) of a pipe (110) having a first circumferential intact sealing region (113) on the inner surface (112) of the pipe end section (111); the tubular connecting part comprising a first radially outwards extending circumferential sealing barb (105) positioned for engaging, when in use, with the first circumferential intact sealing region during shrinkage of the pipe end section for forming a sealing between the pipe fitting and the pipe.