Diaphragm Wall Cutter Drive Housing With Intermediate Pressure Chamber
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Solution Overview
Problem
Existing drive devices for trench wall cutters face challenges in sealing against high external pressures and abrasive environments, leading to inefficiencies and increased temperature issues due to churning losses and the need for bulky compressed gas devices.
Innovation Solution
A pressure compensation system with an intermediate chamber pressurized by a pressure source, sealed from both the interior and exterior, reduces the volume required for pressure equalization, using different seals for internal and external pressures and allowing for independent pressurization of multiple chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire interior of the transmission housing is pressurized to equalize pressure with the environment, then sealing against high external pressure is improved, but the device becomes complex and bulky due to required pressure accumulators or pumps
Solution Approach 1:
The transmission housing is divided into two separate compartments: a first compartment containing the transmission elements and a second compartment forming a pressure compensation chamber. This segmentation allows the pressure compensation system to operate independently with a small volume of pressurizable medium, avoiding the need for large pressure accumulators or pumps that would be required if the entire housing interior were pressurized.
Solution Approach 2:
A seal element is introduced as an intermediary component between the two compartments. This seal element is acted upon by the pressurized medium in the second compartment, which in turn acts on the seal to counterbalance the external hydrostatic pressure on the first compartment. This intermediary approach allows pressure compensation without directly pressurizing the transmission compartment.
2Reliability
If compressed air or gas is used to pressurize the transmission housing interior, then pressure equalization is achieved, but large volumes of compressed gas are required leading to bulky storage tanks or compressors
Solution Approach 1:
The housing interior is segmented into a small second compartment dedicated to pressure compensation, separated from the main transmission compartment. This allows the pressurizable volume to be minimized to only what is necessary for the compensation chamber, eliminating the need for large-volume pressure accumulators or gas storage tanks.
Solution Approach 2:
A pneumatic or hydraulic pressure source is used to generate high pressure in a small volume within the second compartment. This pressurized fluid acts on the seal element to provide the necessary counterbalancing force against external hydrostatic pressure, achieving effective pressure compensation with minimal gas or fluid volume.
3Volume of moving object
If the transmission housing is filled almost completely with lubricating oil to minimize air space, then the volume of pressure medium required is reduced, but churning losses increase sharply leading to temperature problems
Solution Approach 1:
The housing is segmented into two compartments, allowing the lubricating oil to remain only in the first compartment at its necessary level for transmission operation. The second compartment contains a different pressurizable medium (gas or hydraulic fluid) that does not come into contact with rotating transmission elements, thus avoiding churning losses while still providing pressure compensation.
Solution Approach 2:
A seal element acts as an intermediary that transmits the pressure effect from the second compartment to the first compartment without requiring the lubricating oil to be present in the pressurizable space. This allows the use of a small volume of pressurizable medium in the second compartment without causing churning losses, as the pressurizable medium does not directly contact rotating parts.
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 solution provides reliable sealing at high pressures without excessive churning losses or bulky gas devices, maintaining efficiency and reducing the risk of pressure-related issues in deep diaphragm wall construction.
Implementation Method 1
the drive housing has a pressure compensation device in the form of an expandable membrane or a displaceable piston in order to adjust the internal pressure in the housing to the external pressure
Implementation Method 2
The sealing of the drive device represents a major challenge, since it not only has to be sealed against a polluted environment and the abrasive media contained therein, but also against the increased, considerable external pressure due to the depth
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a drive device for a diaphragm wall cutter (1), having a drive housing and/or gear housing (11), which encloses an interior (16) for accommodating drive and/or gear elements and comprises two housing parts (13, 14) which are rotatable relative to one another and which are sealed with respect to one another by a sealing device (15), and having a pressure equalization device (19) for pressure equalization between the interior and the surroundings. The invention also relates to a diaphragm wall cutter having such a drive device. It is proposed here not to pressurize the entire interior of the housing, but only an interspace (20) arranged upstream with respect to the surroundings, and to seal said interspace with respect to the interior on the one hand and with respect to the surroundings on the other hand. According to the invention, the pressure equalization device comprises at least one intermediate chamber (20), which is pressurized by a pressure source and is sealed with respect to the interior by an inner seal (21) and with respect to the surroundings by an outer seal (22). By virtue of such a sealed intermediate chamber between the housing interior and the surroundings that can be considerably smaller in terms of volume than the interior, the pressurization for pressure equalization between interior and surroundings is considerably simpler.