Hollow Piston Access Apparatus for Pressurized Pipes
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Solution Overview
Problem
Existing tools for accessing the interior of pressurized pipes and vessels, such as retrievers, face difficulties in inserting items like cameras with long leads due to the insertion mechanism, and often require the vessel to be drained or decommissioned for inspection or repair, which is inconvenient and costly.
Innovation Solution
An apparatus with a hollow piston and body member that allows a conduit to be introduced into a pressurized pipe, featuring a counter-pressure portion to balance the force exerted by pressurized fluid, enabling the piston to slide in and out while maintaining a pressure seal, thus allowing inspection tools to be inserted without disturbing the internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional retriever insertion mechanism is used, then access to the vessel can be provided, but it becomes difficult to insert items such as cameras having long leads attached thereto
Solution Approach 1:
The apparatus is divided into distinct functional components: a body member that remains outside the vessel, a hollow piston that moves into the vessel, and a conduit that passes through the piston. This segmentation allows the conduit with attached cameras or inspection tools to be inserted independently through the piston without requiring the entire apparatus to be inserted, thereby solving the difficulty of inserting items with long leads.
2Ease of operation
If the vessel is accessed by traditional methods, then inspection or repair work can be performed, but the vessel requires draining or isolation which is inconvenient and expensive
Solution Approach 1:
The hollow piston acts as an intermediary device that bridges the high-pressure environment inside the vessel and the external environment. It provides a sealed passage through which inspection tools and conduits can be inserted and withdrawn without requiring the vessel to be drained or isolated, thereby eliminating the time-consuming decommissioning process while maintaining safety.
3Ease of operation
If the piston is inserted into the pressurized vessel, then access is provided, but the pressure differential creates force opposing insertion
Solution Approach 1:
The apparatus incorporates a counter-pressure portion on the piston that experiences force from the external atmosphere or a pressure source. This counter-force balances the force exerted by the pressurized fluid inside the vessel on the piston's internal volume, thereby neutralizing the net force opposing insertion and making piston movement feasible without requiring excessive external force.
4Reliability
If a pressure seal is maintained between the piston and barrel, then pressure containment is achieved, but the piston movement is constrained
Solution Approach 1:
The seal between the piston and barrel utilizes flexible sealing elements that can deform and adapt as the piston moves. These flexible seals maintain continuous contact with the barrel surface to prevent pressure leakage while accommodating the axial movement of the piston, thereby preserving both pressure containment integrity and piston mobility throughout the insertion and withdrawal cycles.
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
Enables convenient and pressure-safe access to the interior of pressurized pipes and vessels, allowing for the introduction of inspection tools like cameras without disturbing the internal pressure, reducing the need to drain or decommission the vessel.
Implementation Method 1
when an internal volume of the piston is pressurised by a fluid from the object a force exerted by pressurised fluid on the piston in a first axial direction is opposed by a force exerted by pressurised fluid on a counter-pressure portion of the piston
Implementation Method 2
a pressure tight seal is formed between the conduit and conduit orifice
Implementation Method 3
first and second sealing means each arranged to provide a pressure seal between the barrel and the piston at respective first and second axially displaced positions
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
In one aspect of the invention for which protection is sought there is provided an apparatus (1) for providing access to pressurised pipes (24) and the like, the apparatus comprising: a body member (2) having attachment means for attachment of the body member to a pipe or vessel or a fitting coupled to a pipe or vessel, the body member having an internal barrel (6) that may be provided in fluid communication with the pipe or vessel or fitting when the body member is attached to the pipe or vessel or fitting; a hollow piston (3) slidable axially within the internal barrel, the apparatus being configured such that when an internal volume of the piston is pressurised by a fluid from the pipe or vessel a force exerted by pressurised fluid on the piston in a first axial direction is opposed by a force exerted by pressurised fluid on a counter-pressure portion (9, 10) of the piston, the apparatus being provided with a conduit orifice (15) adapted to allow a conduit (16) to be disposed therethrough so as to pass into the apparatus to an interior of the piston, wherein a pressure tight seal (15s) is formed between the conduit and conduit orifice, the apparatus being configured to allow a first end (3a) of the piston to be translated axially into the pipe, vessel or fitting, the piston having a port (21) arranged to allow egress of the conduit from the piston into the pipe, vessel or fitting.