US2095821A - Isochronous governing mechanism - Google Patents

Description

0a. 12, 1937. A. MAAS- 2,095,821

ISOCHRONOUS GOVERNING MECHANISM Filed April 13, 1937 Driven from Tu'r'b'me .Sha

Inventor:

A vndd Mans, bg' fi /pny Hijs Attwwe Patented Oct, 12, 1937 I UNITED 1 STAT-ES.

2,095,821 ISOCHRONOUS GOVERNING MECHANISM Arnold Maas, Berlin-Tegel, Germany, "assignor to General Electric Company, a corporation of New York Application April 16,1937, Serial No. 136,696

In Germany April 21, 1936 4' Claims. i (01.121-42) The present invention relates to isochronous governing mechanisms as are used, for example, to control the flow of elastic fluid to prime movers. In certain cases where a plurality of prime 5 movers are arranged in parallel to drive electric generators connected to a line, it is customary to provide one of the prime movers .with an isochronous governing mechanism to take over load fluctuation, that is, to furnish peak loads and to provide other primemovers for furnishing a base load with an ordinary governing 'mechanism having a rigid follow-up arrangement. At times, for instance where the prime mover furnishing the peak load fails, or where a plant in- 15 eluding such peak load furnishing prime mover is to be connected in parallel with another plant to furnish a fixed load while such other plant is to take over load fluctuations, it becomesdesirable to eliminate the isochronous characteristic 20 of a governing mechanism,'in other words, to change an isochronous governor with elastic or flexible follow-up arrangement into an ordinary governing mechanism withrigid follow-up arrangement.

25 The object of my invention is to provide an improved construction and arrangement of isochronous governing mechanisms which can be readily changed into ordinary governing mechanisms with rigid followrup arrangement.

30 For a consideration of what I believe to be noveland my invention, attention is directed to the following description and the claims appended thereto in combination with the accompanying drawing.

35 The single figure of the drawing illustrates a governing mechanism embodying my invention.

The arrangement comprises an elastic fluid turbine I having an inlet valve II for controlling the flow of elastic fluid thereto. The governing mechanism for positioning the valve ll comprises a regulating device in the present instance a speed governor l2 driven from the tury bine shaft and pivotally connected to the lefthand end of a lever I3 which has an intermediate point supported on a fulcrum l4 and a right-hand end pivoted to the-left-hand end of a governor lever l'5. An-intermediatepoint of the lever I5 is connected to a control member or pilot valve l6 for controlling the flow of 'operating fluid to and from a motor or hydraulic cylinder H. The latter has a piston l8 with astem l9 connected to the prime mover element to be controlled, in the present instance, the valve l I. During operation, an increase in speed due to a decrease in load causes outward movement of the weights of the governor I2 whereby the lever I3 is turned about the fulcrum I 4 in counterclockwise direction, causing upward movement of the left-hand end oflever l5 and of the pilot valve l6, resulting in the supply of operating fluid 5 to the upper sideof the motor piston l8 and a discharge of operating fluid from the lower side thereof. This causes closing movement of the valve II and consequently reduction in flow of elastic fluid to the turbine I 0, resulting in a 10 decrease in speed.

The follow-up mechanism between the motor and the pilot valve for efiecting return motion of the latter upon movement of the motor piston l8 comprises a dashpot having a cylinder 20 mechanically connected to the piston l8 of the hydraulic motor and-a dashpotpiston 2| movably disposed within the cylinder 20. The cylinder is filled with a liquid which during movement of the piston2l is displaced between the upper side 20 and the lower side of the piston through a bypass 22. The piston 2| has a stem 23 connected to the right-hand end of the lever l5 and to a normally balanced spring 24. The connectionbe tween the piston 23 and the right-handend of 25 I the lever IS in accordancewith my invention comprises 'a rod 25 having portions screwthreaded in opposite directions and arranged for rotation by means of a handwheel 26. Two nuts 21 and 28 are held on the oppositely threaded portions of the rod 25. The nuts are linked to a U-shaped member 29 which is secured at its lower end to the upper end of the dashpot pis-' ton stem 23. The nut 21 in addition is connected by a pivot 30 to the right-hand end of the governor lever IS. The spring 24 is held between two plates 3| which have outerportions engaging annular stops 32 and inner' portions engaging abutments 33 and 34 secured to a stem 'or rod 35. The latter has -a lower portion with a 9 slot 36 disposed intermediate the nuts 21, 28, In the position shown, the nuts 21, 28 are forced against the lower slotted portion of the stem 35, thus establishing a mechanical connection between the spring. and the dashpot piston stem 23. In this position upward movement of the daslipot piston stem 23 efiects compression of the spring 24 and subsequent downward movement of the spring rod 35. Thus with the nuts -21, 2s rigidly connected to the lower end of the 9.

cordance with my invention by the provision of means for rigidly connecting the dashpot cylinder with the right-hand end of the lever I5 andv by cutting out the spring 24. This is accomplished by providing thedashpot cylinder 20 with upwardlyprojecting members 31 and 38 having upper portions with slots 39, 40 through which the l ght-hand end of the lever aforementioned screw-threaded rod 25 passes freely to move up and down during isochronous operation. To change from isochronous operation to ordinary governing operation with fixed return motion, the handwheel 26 is turned whereby the nuts 21, 28 are moved outward and are forced against the upper portions of the members or projections 31, 38 to establish rigid connection therewith. In this position the nuts 21, 28 and consequently also the dashpot piston 2| are rigidly connected to the dashpot cylinder 20, hence establishing a rigid connection between the i5 and the hydraulic motor piston l8, With this rigid connectiomup ward movement of the hydraulic motor piston l8 causes like upward movement or the right-hand end of the lever l5 and through'it return movement of the pilot valve It 1 Thus, with my invention 1 have accomplished ,an improved isochronous governing mechanism which can be readily changed into an ordinary governing mechanism with flic 6. return motionbetween the governor lever and the hydraulic.

motor piston. To this end the dashpot piston member and the dashpot member which are connected to the governor lever and the hydraulic motor respectively may be locked together and the normally balanced spring connected to the governor lever during isochronous operation may be disconnected therefrom during operation as ordinary governor with. fixed return motion. 3

Having described the method of operational my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim "as new and desire to secure by Letters Patent of the United States, is:

1. Governing mechanism. for prime m'overs,

comprising a governor lever, a regulating device connected to the lever, a hydraulic motor, a-pilot valve moved by the lever, for controlling the motor and a follow-up mechanism between .the pilot valve and the motor, said follow-up mechanism including a dashpot having a cylinder member with a bypass and a piston member, one of the members being connected to the motor andthe other to the lever, a normally balanced spring connected to the lever, and means for disconnecting the spring and rigidly securing the piston member to the cylinder member.

2. Governing mechanism for prime movers comprising a governor lever, a regulating device connected to the lever, a hydraulic motor having a piston for connection to a prime mover element to be controlled, a pilot valve connected to the lever for controlling the flow of operating fluid to the hydraulic motor, a dashpot having a cylinder member and a piston member, means connecting one of the members to the hydraulic motor piston, means connecting the other member to the governor lever, a normally balanced spring and means for alternately connecting the spring to the other member and for disconnecting the spring from, the other member and simultaneously locking.

the two members together.

3. Governing mechanism for prime movers comprising a governor lever, a regulating device connected to the lever, a motor having an element for connection to a prime mover element to be controlled. a control member for the motor connectedto the lever, means for effecting follow-up connected to the governor lever, a normally balanced spring, means for connecting the spring to the piston, and means for disconnecting the spring from the piston and simultaneously looking the piston to the dashpot cylinder.

4. Governing mechanism for prime movers comprising a governor lever, a speed governor to be driven from the prime'mover being connected to the lever, a hydraulic motor having a piston for connection to a valve for controlling the flow oi fluid to a prime mover, a pilot valve for the motor connected to the governor lever, a dashpot having a cylinder connected to the hydraulic motor piston, a piston having a stem movably arranged in the dashpot, a rod with a handwheel having oppositely threaded portions, two nuts on the. oppositely threaded portions or the handwheel,

links connecting the nuts to the dashpotpiston andthe spring rod-.and rotation of the screwthreaded rod in the opposite direction eflects disconnection of the spring rod from the dashpot piston and rigid connection between the dashpot piston and the dashpot cylinder.

ARNOLD mas.

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