Dry Vacuum Pump Pressurized Bearing Segmentation
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Solution Overview
Problem
The high-speed rotation of rotor shafts in dry vacuum pumps requires specialized bearings that are costly and limited in choice due to the need for lubricants compatible with high vacuum conditions, which restricts the use of more economic bearings and increases costs.
Innovation Solution
A dry vacuum pump design where a high vacuum-side bearing is arranged in a recess with a controlled pressure environment, connected to a region of higher pressure via a duct, allowing the use of more economic bearings and reducing the risk of lubricant gas-out, while maintaining an oil-free seal using a dry sealing device like lip seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized vacuum-compatible bearings are used, then reliability is improved, but cost increases and choice is limited
Solution Approach 1:
The bearing housing is divided into a vacuum chamber portion and an atmosphere chamber portion, with the bearing located in the atmosphere chamber. This segmentation allows the bearing to operate in atmospheric pressure where standard lubricants can be used, while the vacuum chamber maintains high vacuum conditions. The sealing element isolates the two chambers, enabling standard bearings to be used without compromising vacuum reliability.
Solution Approach 2:
A sealing element acts as an intermediary between the vacuum chamber and atmosphere chamber, allowing the bearing to access atmospheric pressure for lubrication while preventing vacuum degradation. The seal enables the bearing to function in a transitional zone where it benefits from atmospheric pressure for lubricant retention while maintaining vacuum integrity on the vacuum side.
2Ease of manufacture
If standard bearings with conventional lubricants are used, then cost is reduced and choice is increased, but lubricant gas-out occurs in high vacuum
Solution Approach 1:
The bearing housing is segmented into vacuum and atmosphere chambers, placing the bearing and its lubricant in the atmosphere chamber where conventional lubricants can operate without gassing. This physical separation allows standard lubricants to be used while preventing their harmful effects in the vacuum chamber.
Solution Approach 2:
The sealing element serves as an intermediary barrier that isolates the lubricant-containing atmosphere chamber from the vacuum chamber. This seal prevents lubricant vapor and gas-out from contaminating the vacuum environment while allowing the bearing to function with conventional lubricants.
3Reliability
If bearings are located in the high vacuum chamber, then vacuum performance is maintained, but lubricant compatibility becomes restricted
Solution Approach 1:
The bearing housing is segmented into two pressure zones, with the bearing located in the atmosphere chamber portion. This segmentation allows the bearing to operate with conventional lubricants while the vacuum chamber portion maintains high vacuum performance. The seal between segments prevents cross-contamination between the two environments.
Solution Approach 2:
The sealing element acts as an intermediary that allows the bearing to be positioned in the atmosphere chamber while still serving the vacuum chamber's rotational needs. This seal enables versatile lubricant selection in the bearing chamber while maintaining vacuum integrity in the vacuum chamber.
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 enables the use of more affordable bearings and reduces the risk of lubricant gas-out, while maintaining high vacuum performance and preventing oil contamination, thus lowering costs and improving operational efficiency.
Implementation Method 1
a first duct (44) connects the recess (42) with a region of the dry vacuum pump in which a higher pressure prevails than in the at least one suction chamber (34) adjacent the high vacuum-side bearing (32)
Implementation Method 2
the seal between the rotor element and the pump housing is oil-free. This offers the particular advantage that no oil-containing air can escape from the dry vacuum pump to contaminate connected apparatuses
Data Source
AI summary
A dry vacuum pump, comprising a pump housing, which forms a plurality of suction chambers, wherein rotor elements are arranged in the suction chambers, in order to convey a pump medium from a high-vacuum-side inlet to an outlet. At least one rotor element is arranged in each suction chamber. The rotor elements are connected to a rotor shaft. The rotor shaft is supported by bearings, wherein a high-vacuum-side bearing is arranged in a cut-out. A sealing device is arranged between the high-vacuum-side bearing and at least one suction chamber adjacent to the high-vacuum-side bearing. The cut-out is connected, by means of a first channel, to a region of the dry vacuum pump in which there is a higher pressure than in at least one suction chamber adjacent to the high-vacuum-side bearing.