Insert Valve Internal Sealing for Pressurized PCCP Replacement
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Solution Overview
Problem
The installation of new valves in prestressed concrete cylinder pipes (PCCP) is challenging due to the need to restrain and cut the high-tension wire without causing pipe rupture or loss of pressure integrity, as existing methods require long areas to be stripped of wire, risking blowout or rupture, and traditional external sealing methods are not effective.
Innovation Solution
A method using temporary and permanent clamps to restrain the tension wire, allowing for the installation of a temporary enclosure to cut and remove pipe sections while pressurized, and employing a butterfly isolator to move internal seals into place for a fluid-tight arrangement, enabling the insertion of new valves without unwinding the wire, applicable to various pipe types including PCCP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional external sealing methods are used to install valves in PCCP pipes, then the valve can be installed, but long areas of the cylinder must be stripped of wire, risking blowout or cylinder rupture
Solution Approach 1:
The sealing process is divided into two distinct phases: temporary internal sealing during valve insertion, and permanent external sealing afterward. This segmentation allows the temporary seal to be placed inside the pipe without stripping wire, while the permanent seal is applied externally after the valve is secured, eliminating the need to compromise cylinder integrity for sealing purposes
Solution Approach 2:
A temporary internal seal acts as an intermediary element that enables valve insertion without requiring wire removal. This temporary seal provides the necessary sealing function during the critical insertion phase, after which it can be removed or left in place while the permanent external seal is applied, thus mediating between the need for valve installation and the need to preserve cylinder integrity
2Ease of manufacture
If bells and spigots are used for joining pipe ends, then connections can be made, but the fittings become much larger than the pipe's diameter, requiring complex mechanical sliding within pressurized enclosures
Solution Approach 1:
Instead of using traditional external bells and spigots that require complex mechanical sliding operations, the invention inverts the approach by using internal seals that are pushed into place from within the pipe. This reversal of the sealing direction simplifies the joining mechanism, eliminating the need for large fittings and complex pressurized enclosure systems
Solution Approach 2:
The sealing function is extracted from the traditional external bell-and-spigot mechanism and relocated to internal seals within the pipe. This extraction allows the joining process to occur without the cumbersome external fittings, reducing device complexity while maintaining connection integrity
3Productivity
If the pipeline remains pressurized during valve insertion, then operational continuity is maintained, but the sealing and cutting operations become more difficult and risky
Solution Approach 1:
Temporary internal seals are installed and positioned before the actual valve insertion and cutting operations begin. This preliminary sealing action creates a controlled environment that allows subsequent operations to be performed safely while the pipeline remains pressurized, maintaining operational continuity without compromising safety
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for the safe and efficient installation of new valves in PCCP pipes by maintaining wire tension and pressure integrity, reducing the complexity and size of fittings, and enabling valve insertion in pressurized systems without risking pipe rupture or wire unwinding.
Implementation Method 1
the spring tube is rolled to provide exterior expansion when pulled together so as to provide an outward pushing force on the sealing member
Implementation Method 2
The present method uses the natural movement of a butterfly isolator to push or move internal seals from a replacement valve into the bores of existing pipe ends
Data Source
AI summary
A method of cutting and removing a section of prestressed concrete cylinder pipe and then installing a replacement valve while the pipeline is fully pressurized uses a replacement valve body (22) with two cylinders (223, 225) that match the openings of the cut pipe (35). Inside each of the two cylinders (223, 225) is a cut-covering assembly (62) which includes a cylindrical elastomeric seal (26) and spring tube (25), and a cross brace (27) extends between two surfaces within the spring tube (25). The replacement valve body (22) further includes a rotatable valve (24) in a central portion of the valve, and when the cylinder ends of the replacement valve body (22) are positioned adjacent the bores of cut pipe ends (36), the valve (24) can be rotated to push the elastomeric seals (26) of each of the cut-covering assemblies (62) into the bores of the cut pipe ends (36), thereby covering gaps (77) created when the pipe (35) was cut and placing the pipe ends (36) in fluid-tight engagement with the replacement valve body (22).