US2317812A - Governor apparatus - Google Patents

Description

M1121, 1943. y scam 2,317,812

GOVERNOR APPARATUS Filed Ju1y rev,l 19`4'o lwkwmq l 4 Wren ScHMm.

ATTORNEY` Patented Apr. 27, 1943 GOVERNOR APPARATUS Walter Schmid, Philadelphia, Pa., assignor to Westinghouse Electric & ManufacturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 27, 1940, Serial No. 347,908

(Cl. 'I4-3) 2 Claims.

My invention relates to an emergency or overspeed governor and it has for an object to provide apparatus of this character which is sparkless in operation and therefore safer in inflammatory or explosive media environments.

The usual overspeed governor includes a me tallic weight or pin movable diametrally of the rotating shaft of the prime mover or turbine upon overspeeding to strike and trip a lever to close the throttle valve. Usually the lever is made of metal and impact of the pin therewith involves metal-to-metal contact. While this arrangement is ordinarily satisfactory, yet, where the prime mover is rotated in an enclosure likely to have highly inflammatory or explosive media, as is the case with certain oil refineries, the hazard of re or explosion is encountered on account of sparking due to the metal-to-metal contact of the pin with the lever. While attempts have been made to alleviate this diiculty by making the trip lever of spark-resisting metal, for example, brass or other special metals, nevertheless, not only will these metals spark under certain conditions, but they are so soft that frequent replacement is required. Also, attempts have been made to meet the inflammatory and explosive condition by having the prime mover enclosed in a conduit communicating with space external to the inflammatory and explosion zone.

I have found that the foregoing objections may be overcome by making at least the contact portion of the trip lever of suitable hard and wearresisting non-metallic material to avoid metalto-metal contact and consequent sparking. The material may comprise, for example, linen or canvas impregnated with a suitable amorphous or resinous substance such as a phenolic condensation product. Such a material, not only has the advantage of avoiding metal-to-metal contact and the consequent danger of sparking with the possibility of explosion, thereby making it possible to install fluid-operated prime movers in situations heretofore regarded as too hazardous, but installation may be effected without the cumbersome and expensive equipment to make it explosion-proof and the material has the ad' terial so as to avoid metal-to-metal contact and consequent sparking.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a partial sectional view showing an overspeed trip mechanism with my improved structure;

Fig, 2 is an enlarged partial sectional view showing the trip lever; and,

Fig. 3 is a sectional view taken along the line III-III of Fig. 2. i

Referring now to the drawing more in detail, I show an overspeed governing mechanism I U, mounted in a casing II, in which rotates a turbine shaft I2. A weight or trip pin I3 is carried in an opening I4 extending diametrally of the shaft I2. The weight has its center of gravity slightly offset from the axis of rotation and normally, it is held in place by a compression spring I 5 and a retainer I6. When the Weight ilies out, it trips the arm I'I of the multiple arm lever I8 to release mechanism, at I9, to permit the spring 20 to close the throttle valve 2 I.

As heretofore pointed out, at least that portion of the lever arm I1 contacted by the pin I3 is made of suitable hard, wear-resisting, non-sparking, amorphous material. For this purpose, I prefer to use fabric, such as linen or canvas, im-

pregnated with a resin such as a phenolic conf densation product; andv this composite structure is preferably embodied as an insert or facing 22 for the lever arm I'I and positioned for contact by the pin.

While the insert or facing may be attached to the lever arm II in any suitable manner, I preferably provide the latter with a recess 23 open at the sides and having dovetail ends 24. The insert is formed with dovetail ends 25 to iit the recess ends 24; and, with the insert positioned in the recess, it isretained by lap plates 26 detachably secured to the sides of the lever arm.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications Without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

' What is claimed is:

l. In apparatus for use in inflammatory or explosive environments, a shaft rotatable norpredetermined extent to engage thel lever and p then, with continued outward radial movement, l0

f outward radial movement, to engage the lever to engage the lever repeatedly to move the latter the amount required to release the trip mechay resisting and nonsparking material including l fabric impregnated with a suitable synthetic resin.

2. In apparatus for use in inflammatory or explosive environments, a shaft rotatable nor`- mally at a relatively high speed, trip mechanism including a lever disposed adjacent to the shaft and movable outwardly therefrom to release the mechanism and a pin carried by the shaft so as to be normally free of the lever but which, under the inence lof its centrifugal force,ris movable radially outward with respect to the shaft when the latter overspeeds to a predetermined extent to engage the lever and then, with continued repeatedly to move the latter the amount required to release the trip mechanism, said lever having a pin-contact facing comprised by a hard, tough,"wear,resisting and non-sparking material including fabric impregnated with a suitable synthetic resin.

WALTER SCHMID.

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