Wear sensing means for rotary compressor

Aug. 26,1969 j. κ. kilbane 3,463,384

WEAR SENSING MEANS FOR ROTARY COMPRESSOR Filed July 26, 1967

<img file="US3463384A_D0001.tif" />

<img file="US3463384A_D0002.tif" />

<img file="US3463384A_D0003.tif" />

United States Patent Office

3,463,384

Patented Aug. 26, 1969

3,463,384

WEAR SENSING MEANS FOR ROTARY COMPRESSOR John K. Kilbane, Wauwatosa, Wis., assignor to AllisChalmers Manufacturing Company, Milwaukee, Wis. Filed July 26, 1967, Ser. No. 656,274 Int. CI. F04b 39/00, 49/00

U.S. Cl. 230—138 5 Claims

ABSTRACT OF THE DISCLOSURE ¹⁰

A sliding vane rotary compressor with openings at the bottom of the vanes which short circuit adjacent pressure chambers after a predetermined amount of wear has taken place on the vanes, and means for indicating when 15 the short circuit has occurred.

This invention pertains in general to rotary compressors 20 and more particularly to a means to sense the wear on the compressor vanes.

Sliding vane rotary compressors have few moving parts and therefore require little maintenance. However, periodically it is necessary to disassemble the machine to 25 determine whether or not the vanes need to be replaced. . It is a general object and the intention of this invention to provide a means for determining when the vanes of a rotary compressor need to be replaced which does not require a disassembly of the machine. 30

A further object of the subject invention is to provide a rotary compressor of the sliding vane type with means which provides a short circuiting of one compression chamber to the next after a predetermined amount of wear has taken place on the compressor vanes. 35

A more specific object of this invention is to provide a rotary compressor of the hereinbefore described type with means which will cause a change in pressure and temperature of the fiuid in the compressor after a predetermined amount of wear has taken place on the rotary ⁴⁰vanes and including means which will sense this change.

These and other objects of the subject invention will become more fully apparent as the following description is read in light of the attached drawings wherein:

FIG. 1 is an isometric view partially broken away ⁴⁵showing a rotary compressor constructed in accordance with the invention and including temperature sensing means;

FIG. 2 is a side elevation of a modified form of sliding vane; and ⁵⁰

FIG. 3 is a view taken along the line II—Π in FIG. 2.

Referring to the drawings, a rotary compressor generally designated 6 is shown constructed in accordance with the invention. The compressor comprises an outer cylindrical casing 7 having end closures 8. A shaft 9 ⁵⁵extends through the compressor end closures and rotatably mounts a rotor 11 within the casing 7. The rotor is provided with a plurality of radially directed circumferentially spaced slots 12. In each of these slots is received a sliding vane 13. ⁰⁰

The rotor is mounted eccentrically with relation to the longitudinal center line of the compressor casing so that upon rotation of the rotor the vanes 13 will be forced inward due to contact with the rotor casing and will move outward under the influence of centrifugal ⁶⁵force. The vanes 13, rotor 11 and casing 7 define pressure chambers 15.

As shown in FIG. 1, one form of the compressor vanes 13 may have one or more openings 14 extending completely through the lower portion of the vane. As the ⁷ vanes wear, due to the relative sliding motion between their outer surface and the compressor casing, the vane will extend further out of the slot 12. When the highest point on the openings 14 pass above the rotor surface, a direct short circuit between the two adjacent compression chambers 15 exists. Therefore, the higher pressure gas in the smaller chamber will seep back into the lower pressure gas and will be worked upon again as the rotor rotates. This will cause an increase in the temperature of the gas. This increase in temperature will be a substantial rise as compared to the rise in the temperature as the gas is compressed in the ordinary maimer.

A temperature sensing means 16 is provided in the compressor casing 7. The sensing means 16 senses the unusual increase in the temperature of the gas and sends a signal to the thermocouple alarm 17. This signal is then transferred to a motor control switch 18 which shuts down the compressor and also sends a signal to an alarm enunciator 19 which may either sound an alarm or turn on a light to indicate to the operator that the compressor vanes need replacing.

FIGS. 2 and 3 show a modified form of compressor vane. In this modified form a groove 21 is provided in the lower portion of the compressor vane. This groove is of sufficient depth so that it will wear through due to the friction between the surface of the vane and the sides of the slots 12. The depth of the groove 21 is such that it will wear through when a predetermined amount of wear has taken place on the vane 13. A direct short circuit will then occur between the two adjacent compression chambers. This again will sound the alarm in the same manner as indicated above.

Although only two embodiments of the subject invention have been herein shown and described, other embodiments will be obvious to those skilled in the art after reading this description and it is intended that all such embodiments as come within a reasonable interpretation of the appended claims be covered.