Two-Port Percussion Mole With Check Valve for Geothermal Loop Insertion
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Solution Overview
Problem
Current methods for installing geothermal heat-pump systems require expensive and cumbersome drilling equipment, especially in urban areas with limited access, and existing percussion moles are inefficient in inserting pipes at deep angles or vertically due to high friction and lack of end-access.
Innovation Solution
A percussion mole with a non-return valve system that allows the same pipes to be used for both insertion and heat transfer, utilizing a driving fluid for insertion and switching to a heat-exchange fluid for operation, and incorporating design features like a wider head for reduced friction and a bleed mechanism to manage liquid accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional drilling and boring machines are used to create holes for geothermal heat-pump systems, then holes can be created at deep angles or vertically, but the equipment is expensive and cumbersome and requires significant access space
Solution Approach 1:
The patent replaces conventional mechanical drilling systems with a percussion mole that uses pneumatic power transmission. Compressed air is delivered through the second pipe to drive a piston that creates percussive motion, substituting heavy mechanical drilling equipment with a lighter, pneumatically-driven system that can be inserted through existing access points.
Solution Approach 2:
The patent employs pneumatic principles by using compressed air transmitted through the second pipe to power the percussion mechanism. The air pressure drives the piston back and forth, creating the percussive action needed to advance the mole through the ground without requiring heavy mechanical equipment.
2Ease of operation
If percussion moles are used to insert pipes at deep angles or vertically, then installation access is improved, but friction between the casing and ground increases significantly
Solution Approach 1:
The patent makes the system dynamic by using a reciprocating piston that alternates between forward striking motion (advancing the mole) and rearward return motion (resetting for the next strike). This dynamic operation allows the mole to overcome friction progressively through repeated percussive cycles rather than requiring continuous high force.
Solution Approach 2:
The percussion mechanism operates through periodic action, with the piston delivering repeated strikes at regular intervals. Each cycle consists of a forward stroke that advances the mole and a rearward stroke that prepares for the next strike, creating a rhythmic percussive motion that effectively penetrates the ground despite friction.
3Adaptability or versatility
If separate pipes are used for driving the mole and for heat transfer, then insertion and operation functions are independent, but the system complexity and cost increase
Solution Approach 1:
The patent makes the second pipe universal by using it for dual purposes: transmitting compressed air during installation and transferring heat during operation. The non-return valve enables this multi-functionality by directing fluid flow appropriately - allowing air in during insertion while preventing backflow during heat pump operation.
Solution Approach 2:
The patent merges the functions of the second pipe, combining the driving fluid delivery function with the heat transfer function into a single pipe system. This consolidation reduces the number of components required while the non-return valve manages the different functional requirements of each operation phase.
4Device complexity
If the same pipes are used for both driving fluid delivery and heat transfer, then system complexity is reduced, but fluid flow control becomes more difficult
Solution Approach 1:
The non-return valve acts as an intermediary device that mediates between the driving fluid delivery function and the heat transfer function. It controls fluid flow direction based on operational phase - permitting compressed air flow during insertion while preventing heat exchange fluid from flowing backward, thus simplifying the pipe system while maintaining flow control.
Solution Approach 2:
The non-return valve provides dynamic flow control that adapts to different operational phases. During mole insertion, it allows compressed air to pass through; during heat pump operation, it automatically prevents backflow of heat exchange fluid. This dynamic behavior simplifies the overall system while maintaining proper fluid control.
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 efficient and cost-effective installation of geothermal heat-pump systems by reducing equipment costs and improving insertion efficiency at deep angles, with minimal friction and effective heat transfer, while maintaining system integrity and thermal conductivity.
Implementation Method 1
a non-return valve arranged to restrict flow of the driving fluid from the first passage to the second passage during insertion of the ground-loop but permit flow in the opposite direction
Implementation Method 2
The mole is driven by compressed air, provided along a rear-mounted compressed air hose. An internal piston having significant mass is caused to travel rapidly forwards within the tubular casing of the mole, where it strikes the forward end of the casing, driving the casing forwards
Implementation Method 3
An internal piston having significant mass is caused to travel rapidly forwards within the tubular casing of the mole, where it strikes the forward end of the casing, driving the casing forwards, displacing the ground around the casing in the process
Implementation Method 4
Energy dissipated during rearward travel of the internal piston and its subsequent reversal is insufficient to overcome the friction between the casing and the ground compressed around it; therefore, the casing does not travel backwards during this part of the cycle
Implementation Method 5
heat energy is transferred between the ground and the pump system via a thermally-conductive loop of pipe laid in the ground
Implementation Method 6
The pipe contains a fluid, which is circulated by a pump to transfer heat energy around the system
Data Source
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AI summary
A percussion mole for inserting a ground-loop for a geothermal heat-pump apparatus. The ground-loop includes a first pipe and a second pipe. The mole comprises: a percussive drive mechanism;a first passage connectable to the first pipe, for receiving a driving fluid via the first pipe and delivering it to the drive mechanism, during insertion of the ground-loop;a second passage connectable to the second pipe, for exhausting the driving fluid from the drive mechanism via the second pipe, during insertion of the ground-loop; and a connection connecting the first passage with the second passage. The connection includes a non-return valve arranged to restrict flow of the driving fluid from the first passage to the second passage during insertion of the ground-loop but permit flow in the opposite direction,whereby after insertion, when the heat pump apparatus is in use, the ground-loop comprises the first and second pipes; the first and second passages; and the connection.