Lubricated Vacuum Pump Suction Valve Pressure Equalization
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Solution Overview
Problem
Existing lubricated vacuum pumps face challenges in effectively controlling the closure of the suction valve during pump shutdown or failure, leading to pressure imbalances and potential contamination of the suction chamber with oil.
Innovation Solution
A lubricated vacuum pump design featuring a stator body with an eccentric rotor, a suction valve, a chamber for lubricating liquid, and a connecting duct that extends into the suction chamber, allowing for the introduction of air to equalize pressure and ensure valve closure, along with a discharge valve system to manage lubricant flow and prevent air ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suction valve remains closed during pump shutdown, then the vacuum level is maintained and oil is prevented from entering the suction chamber, but the pressure in the suction chamber becomes imbalanced and may prevent proper valve operation
Solution Approach 1:
The patent introduces a compensating channel that allows air to enter the suction chamber during shutdown, acting as an intermediary to balance the pressure between the suction chamber and the upstream side of the suction valve. This pressure equalization prevents the harmful pressure imbalance that would otherwise occur when the suction valve remains closed to maintain vacuum.
2Reliability
If the discharge valve allows oil to flow into the containment chamber during operation, then lubrication is provided, but during shutdown the oil flow decreases and air may ingress through the valve orifice into the suction chamber
Solution Approach 1:
The patent extracts the harmful function of air ingress through the discharge valve by providing a dedicated compensating channel that is specifically designed to allow controlled air entry. This separates the lubrication function (handled by the discharge valve and oil flow) from the pressure balancing function (handled by the compensating channel), preventing air from entering through the valve orifice.
3Reliability
If compensation channels are used to balance pressure and close the suction valve during shutdown, then valve closure is achieved, but the system complexity increases with additional channels and segments
Solution Approach 1:
The patent merges the compensating channel directly into the stator body structure, combining the pressure balancing function with the existing housing. This integration approach reduces the number of separate components and simplifies the overall structure compared to having standalone compensation channels or complex segmented valve arrangements.
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 design ensures reliable closure of the suction valve during pump failure, maintaining vacuum integrity and preventing oil from entering the suction chamber, thereby maintaining operational efficiency and reducing noise.
Implementation Method 1
allowing for the introduction of air to equalize pressure and ensure valve closure
Implementation Method 2
a discharge valve system to manage lubricant flow and prevent air ingress
Implementation Method 3
a suction valve whose opening and closing is determined by the pressure difference between the air volume upstream of the channel and the suction chamber
Data Source
Figure 1
Figure 2
AI summary
Described is a lubricated vacuum pump comprising a stator body (2) having a compartment (3) for housing a rotor (4) positioned eccentrically inside the compartment (3) to define a suction chamber (5) having a supply duct (6) and one or more discharge ducts (7); a suction valve (10), positioned along the supply duct (6), configured for passing from an open position to a closed position and vice versa, adjusting the passage of a gaseous fluid in the suction chamber (5); a chamber for containing lubricating liquid (11), in fluid communication with the one or more discharge ducts (7), which has a dividing wall (12) which delimits a compartment (13) for containing the lubricating liquid, into which lead the one or more discharge ducts (7); a discharge valve (16), configured to pass from an open position to a closed position and vice versa, which adjusts the passage of a dispersion of lubricating fluid in the gaseous fluid from a respective discharge duct (7) to the compartment (13) for containing the lubricating fluid; the pump (1) has at least one duct (17) for connecting the chamber for containing lubricating liquid (11) with the suction chamber (5); the connecting duct (17) extends at least partly in the dividing wall (12) of the chamber for containing lubricating liquid (11) and leads inside the suction chamber (5).