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Hermetically sealed shaft seal
PATENTS disc, but pressure from the underside of the seal pushes it onto the disc. Because of the small area of contact, less torque is needed to open the valve. Figure 3 shows the valve in the closed position inside pipe 22. At the end of shaft 52, lever 66 presses against pin 54. At the required pressure, the pin breaks, so that the valve opens, rotating about shaft 52. Other mechanisms are suggested for operating the valve. Instead of a pin which breaks, a linear spring can be designed to deflect at the required pressure. Also, a torsion spring or a counterweight can be fitted directly to the valve shaft.
Hermetically sealed shaft seal Title: Lipped sealing ring having wax packed in helical grooves to facilitate testing upon installation. Patent number: US5755444 Date: 26 May 1998 Inventors: P Carnis, G Pataille
Assignee: Carl Freudenberg This patent concerns sealing-ring shaft seals which are fitted using automatic assembly devices. To test that they are fitted correctly, the assemblies are filled with compressed air, and the loss in pressure is measured. The seal described in this patent is hermetically sealed onto the shaft, to make these tests less time-consuming and more reliable.
Figure 4 shows the seal assembly. The seal consists of a sealing ring 2, which is a flat annular disc, and shoulder 3 which presses on shaft 1. A helical groove in the shoulder drives any leaking oil back into the enclosure. The seal is fixed to metal ring 8 which fits into jacket 5. The jacket incorporates dust seal 6. The inside diameter of the sealing ring is less than the shaft diameter, so that if properly fitted, the inside edge of the ring is deflected by the shaft inwards, into the enclosure, towards space A. If the inside edge is deflected outwards (towards space B), the compressed air tests will show a rapid loss in pressure.
To create the hermetic seal, wax is inserted between the shoulder and the surface of the shaft. There could be a number of shaft assemblies, each with a differently-shaped shoulder, and normally the testing apparatus would have to be recalibrated for each type of assembly. This timeconsuming re-calibration is avoided, because all the seals are hermetically sealed.
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SealingTechnology No. 75
Hermetically sealed shaft seal Title: Lipped sealing ring having wax packed in helical grooves to facilitate testing upon installation. Patent number: US5755444 Date: 26 May 1998 Inventors: P Carnis, G Pataille
Assignee: Carl Freudenberg This patent concerns sealing-ring shaft seals which are fitted using automatic assembly devices. To test that they are fitted correctly, the assemblies are filled with compressed air, and the loss in pressure is measured. The seal described in this patent is hermetically sealed onto the shaft, to make these tests less time-consuming and more reliable.
Figure 4 shows the seal assembly. The seal consists of a sealing ring 2, which is a flat annular disc, and shoulder 3 which presses on shaft 1. A helical groove in the shoulder drives any leaking oil back into the enclosure. The seal is fixed to metal ring 8 which fits into jacket 5. The jacket incorporates dust seal 6. The inside diameter of the sealing ring is less than the shaft diameter, so that if properly fitted, the inside edge of the ring is deflected by the shaft inwards, into the enclosure, towards space A. If the inside edge is deflected outwards (towards space B), the compressed air tests will show a rapid loss in pressure.
To create the hermetic seal, wax is inserted between the shoulder and the surface of the shaft. There could be a number of shaft assemblies, each with a differently-shaped shoulder, and normally the testing apparatus would have to be recalibrated for each type of assembly. This timeconsuming re-calibration is avoided, because all the seals are hermetically sealed.
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SealingTechnology No. 75