Double Mechanical Seal Circulation for Leak and Heat Control
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Solution Overview
Problem
The existing sealing systems for centrifugal pumps are inadequate in preventing leakage of toxic or flammable fluids into the atmosphere during normal operation and power failures, and they fail to effectively cool the double mechanical seal and pump mechanism, leading to potential temperature increases and reduced sealing efficacy.
Innovation Solution
A sealing system with a double mechanical seal, a pump mechanism driven by a rotational shaft, and a fluid barrier-and-cooling medium circulation system that includes a heat exchanger and a shut-off valve, along with a power failure detector and system controller to manage fluid pressure and flow, ensuring the sealing system remains effective during normal operation and power failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump mechanism pressurizes the fluid barrier-and-cooling medium to prevent leakage, then sealing reliability is improved, but heat generation increases causing temperature rise
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary component between the pump mechanism and the fluid barrier-and-cooling medium circulation system. This heat exchanger actively removes heat generated by the pump mechanism, allowing the system to maintain high sealing reliability through continuous pressurization while preventing temperature rise that would compromise system integrity.
Solution Approach 2:
The patent establishes a continuous circulation system for the fluid barrier-and-cooling medium that operates throughout pump operation. The medium continuously absorbs heat from the pump mechanism and is cooled in the heat exchanger, enabling sustained high-pressure operation for leakage prevention without accumulating harmful heat.
2Temperature
If the recirculating system cools the fluid barrier-and-cooling medium, then temperature control is improved, but system complexity increases
Solution Approach 1:
The patent designs the fluid barrier-and-cooling medium to serve multiple functions simultaneously: it acts as a barrier fluid to prevent leakage of process fluid, a cooling medium to remove heat from the pump mechanism, and a lubricant for the mechanical seal surfaces. This multi-functionality reduces the need for separate systems and minimizes overall system complexity while achieving effective temperature control.
3Reliability
If the pump mechanism operates continuously to maintain pressure, then leakage prevention is improved, but energy consumption increases
Solution Approach 1:
The patent implements a continuous operation mode for the pump mechanism to maintain constant pressure in the fluid barrier-and-cooling medium, ensuring reliable leakage prevention. This continuous operation, combined with the cooling system, allows the pump to operate efficiently at steady state rather than cycling on and off, optimizing energy consumption while maintaining 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
The system effectively prevents leakage of toxic or flammable fluids into the atmosphere, maintains the sealing integrity, and cools the double mechanical seal and pump mechanism, preventing temperature increases and ensuring the safety and efficiency of the centrifugal pump operation.
Implementation Method 1
a heat exchanger and a shut-off valve attached to the first medium circulation line
Implementation Method 2
The pump mechanism 119 pressurizes a fluid barrier-and-cooling medium such that the medium has a pressure Pb higher than a discharge pressure Ph of the pump impeller
Data Source
Figure 1
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AI summary
A sealing system includes: a double mechanical seal having a pump-side sealing mechanism (10, 12) and an atmospheric-side sealing mechanism (11, 13); a pump mechanism (19) driven by a rotational shaft (1); a first medium circulation line (30) for circulating a fluid barrier-and-cooling medium between a first chamber (22a) and a second chamber (22b), the first medium circulation line (30) being coupled to the first chamber (22a) and the second chamber (22b), the fluid barrier-and-cooling medium being different from a fluid handled by the centrifugal pump; a heat exchanger (21) and a shut-off valve (28) attached to the first medium circulation line (30); a second medium circulation line (31) bypassing the shut-off valve (28); and a medium pressurizing pump (45) and an on-off valve (23) attached to the second medium circulation line (31).