Double Mechanical Seal Cartridge With Integrated Cooling Pump
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Solution Overview
Problem
Existing cartridge devices with double mechanical seals face issues with heat dissipation at low mixer shaft revolutions below 1000 rpm, leading to seal overheating and reduced reliability without auxiliary pumps, and require additional equipment for effective cooling.
Innovation Solution
A cartridge device with a double mechanical seal incorporating a volumetric pump and a stator-rotor configuration with spring-biased vanes, integrated into the cartridge space to facilitate fluid flow for cooling, eliminating the need for auxiliary pumps by ensuring efficient heat dissipation at low rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If natural circulation or pumping ring/screw is used for cooling, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The cooling function is merged with the existing mechanical seal structure by integrating the volumetric pump into the cartridge device housing. The pump utilizes the process fluid itself for cooling, combining the sealing and cooling functions into a single integrated system, thereby improving cooling effectiveness without significantly increasing device complexity
Solution Approach 2:
The volumetric pump is designed to be driven by the process fluid flow itself, creating a self-regulating cooling system. The pump automatically adjusts its operation based on the available fluid pressure and flow, eliminating the need for external power sources or complex control systems while maintaining effective cooling
2Temperature
If auxiliary circulation pump is installed for forced flow increase, then heat dissipation is improved, but energy consumption increases
Solution Approach 1:
The volumetric pump is driven by the pressure differential of the process fluid itself, converting the kinetic energy of the flowing fluid into pumping action. This self-driven mechanism provides forced circulation and enhanced heat dissipation without requiring external power sources, thereby improving energy efficiency
Solution Approach 2:
The high-temperature process fluid, which would normally be a harmful factor causing seal overheating, is converted into a beneficial cooling agent. The hot fluid drives the volumetric pump through its pressure and flow, and simultaneously serves as the cooling medium that absorbs heat from the mechanical seal faces
3Temperature
If volumetric pump is integrated in cartridge space, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The volumetric pump is nested within the existing cartridge device housing and seal chamber structure. The pump components are arranged concentrically and integrated into the available space between the process seal and atmosphere seal, utilizing the existing cartridge geometry to accommodate the cooling mechanism without requiring additional external components
Solution Approach 2:
The cartridge device housing is designed to serve multiple functions: it houses the mechanical seals, contains the process fluid, and accommodates the volumetric pump. The same housing structure that provides sealing also provides the cooling function, eliminating the need for separate cooling system components
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 solution provides effective cooling of mechanical seals even at low rotational speeds, enhancing energy efficiency and operational reliability by maintaining smooth operation with moderate shaft displacement and reducing the need for additional equipment.
Implementation Method 1
a volumetric pump integrated in the cartridge space to divide it in two portions, the volumetric pump comprising a stator arranged inside the cartridge device housing and having an inner cylindrical wall arranged eccentrically with respect to its outer cylindrical wall, a rotor having at least four, preferably exactly four spring biased sliding vanes
Implementation Method 2
A pumping ring or a pumping screw is an efficient solution to dissipating heat at mixer shaft rotation speeds exceeding 1000 rpm. At shaft rotation speeds lower than the above-indicated one, a fluid film is not created between the static and dynamic faces of the mechanical seal, so the faces are in a constant frictional contact and this leads to higher heat generation and a need to dissipate more heat.
Implementation Method 3
a rotor having at least four, preferably exactly four spring biased sliding vanes, the rotor being arranged on the outer circumference of the seal sleeve and arranged in the stator centrally with respect to the outer cylindrical wall of the stator
Data Source
Figure 1
Figure 2
Figure 3~4c
AI summary
The invention relates to a cartridge device (1) provided with a double mechanical seal to seal a drive shaft of a mixer etc. and comprising a seal sleeve (10) adapted to receive a drive shaft (11) of a mixer; a cartridge device housing (20) mounted on the seal sleeve (10); a process mechanical seal (30); an atmospheric mechanical seal (40); a cartridge space (50) being intended to receive a cooling fluid; and a volumetric pump (60) integrated in the cartridge space to divide it in two portions, the volumetric pump comprising a stator (61) arranged inside the housing (20) and having an inner cylindrical wall arranged eccentrically with respect to its outer cylindrical wall, a rotor (62) having four spring biased sliding vanes (63) and arranged on the outer circumference of the seal sleeve and in the stator (61) centrally with respect to the outer cylindrical wall of the stator, and two axial plates (64, 65) laterally closing the rotor, the first axial plate (64) being provided with an inlet port (66) and the second axial plate being provided with an outlet port (67) arranged in the radial direction of the cartridge device diametrically opposite the inlet port, wherein the cartridge device housing is provided with two apertures (24, 25) intended for the attachment of ducts (71, 72) of a heat exchanger (70). The advantage of the cartridge device of the invention is to provide a sufficient flow of the cooling fluid to cool the faces of the mechanical seals even when used in high-temperature applications and/or applications having low rotational speeds.