US1633180A - Governing device - Google Patents

Description

June 21,1927a y 1,633,180

T. JACKSON GOVERNLNG DEVICE Filed Aug.. 24, 1923 his AHovneg Patented June 21., 1927.

UNITED slriiri-:s

.PATENT oFFicE- THOMAS JACKSON, on LONDON,` ENGLAND, Assieivon rro GLENDORA Bassin' RAMSAY,

' on FoLKEsroNE, ENGLAND.

GOVERNING DEVICE.

Application filed August 24, 1923, Serial No. 659,077, and in Great Britain August 31, 1922.

lever through two oppositely disposed yield@V ing resistan'ces, a lciiurcated pivotcd lever having two abiitmentsv saidfbiturcated lever being adaptedY to be angularly displaced when the lever carrying the mass contacts with either oi" the abutments, a valve device mechanically associated with and operable by the bifurcated lever adapted to permit` passage ot' motive fluid under pressure' when the biturcated leveris angularly displaced, a fluid pressure operated control device connected directly or indirectly to the delivery irom the valve device said control device acting against Van increasing yielding resistance and being adapted to return toits initial position on interruption ot the supply of tluid pressure, connecting means between the control device andy that which directly controls the speed of that which is to be controlled and a source ot motive fluid.

Referring. to the drawings, which form part ot this speciticatiom- Figure l is a front'el-evation of a governing device constructed in accordance with thisinvention. V

Figure 2 is a fragmentary plan view of Fig. l. v v Fig. 3 isl an enlarged section through the valve device operated by the momentum ot the reciprocating mass tor governing.r

Figure '4 is an enlarged section of one form of the valve device associated with the fluid pressure operated control cylinder.

The device illustrated in the drawings is arranged to employ compressed air or steam under unvarying pressure as motive fluid, the pivoted lever a, which for constructional purposes is bifurcated, is adapted to` be reciprocated by the rod connected to a moving part ofV thatv which is" to-abe' controlled,

a secondpivoted lever c carrying' a mass l beingmechanically associated with the leverY t by means ot two adjustable springs c e or the like, so that when the lever a is oscillated it in turn oscillates the lever c.

l It will be seen that owing tothe yielding nature ot the connection between the levers i and c when t-he lever a is oscillated at a certain speed the leverV c will substantially follow its oscillations but when the "speed oit the lever a is increased beyond a certain speed the lever c will havea greatery amplitude of motion due to the inertia fof the mass CZ, the critical speed being entirely dependent upon the strength ot the springs e e or the like employed or the position of the mass Z on the lever c.

The lever c duringr its oscillations 0p- 'erates between stops y vand g mounted on a pivoted biturcated lever L, the distance be'- tween the stops fand g when adj-usted for a specific speed being'suiiicient to permit ot the normal oscillation at that speed of* the lever c without contacty therewith, so V that while the oscillation of the lever c is normal no displacement of the lever-7L takes place; when however, the oscillation of the lever c becomes abnormal due to increase ot speed above that predetermined, the stops f and g on lever It are contacted by the lever c and the lever It is langularly displaced.

The lever L is mounted on' the partl of vthe stem z' which protrudes through the cover ot the valve device le which includes a valve seatrZ, a-ball valve Land ball engagingmember a which is carried and operatedby the part of the stem le' within the device v.

The ball engaging member m. as illustra-ted is provided with four arms cachot which can be employed toV operate the' valve m l as required. i

When the lever h is in mid position one of the arms ofvv the ball engaging member; a is also in midposition withA the result that the ball valve m engages lwith'V its seat Z thus preventing passage of vmotive iuid lthrough the device c, but` when the lever i; is displaced `from the mid posi-tion one or other y of the projections nfof the member n will engage with. the ball manddisplace it from its seat Zf thus .premitting motive fluid ,toy ilow through the' devicek..

The exi-t connection of the device 7c is connected to a power control cylinder 0 containing a piston 20 so that when the motive fluid at constant pressure passes through the device is the piston p is displaced against an increasing yielding resistance such as the spring p.

To control the distance through which the piston 20 is displaced by the motive fluid a power operated valve acting against an adjustable yielding resistance is inserted in the operative end of the cylinder 0 and is adapted to allow any excess vbeyond a predetermined pressure in the cylinder 0 to escape.

As illustrated the power operated valve comprises a plunger g hay/'ing portways r therein said portways fr registering with portways s in the body t during operation of the device, a springu and finger operable adjusting means o being provided to introduce the requisite yielding` resistance.

in operation motive fluid is supplied to the tube at the extreme right handv side of Figures l and 1i, the pressure of' this motive fluid is always the same. lf the spring u were not in placethen the piston Q would pass to the extreme left hand end of its travel. The presence of the spring u however prevents this and the spring u is so adjusted that when the motive fluid is applied the piston g moves to th-e left onlysuch amount as partially will cut off the passage of fluid through the portways 1 and s a small escape of motive fluid always freely taking place.

When the pressure of the motive fluid has been settled for any given plant then the spring u is adjusted by the finger operable adjusting means o so that the portway r slightly overlaps the portway s when the motive fluid exerts pressure on the piston Q. After the spring u has been so adjusted' the pressure of the motive fluid must not be varied.

To ensure that the piston y shall move smartly as soon the motive fluid is admitted, the axial portway which establishes connection between the transverse portway r and the operative endof the piston g is of comparatively small diameter'. In a piston one inch in diameter, the diameter of the axial portway may be one sixteenth of one inch in which case the area of the axial portway is only one two hundred and fifty sixth part of the area of the piston Q.

`When motive fluid is admitted under working conditions the piston q. moves to the left until the force exerted by compressing the spring u is equal tothe force exerted by the motive fluid on the end of the piston g; the piston p is also raised bythe motive fluid until the force exerted by compressing the spring 20 is equal to the force exerted by the motive fluid on the piston p.

The force available for operating the piston p can be adjusted by varying the amount of leakage which is permitted to take place through the portways 1 and s and thus the travel of the piston j? on operation can be controlled within wide limits by adjusting the spring u. n

rlhe arrangement outlined above is Vdouble-acting in operation inasmuch as if the velocity of the oscillations of the lever a in either direction is in excess of that predetermined by adjusting the spring c. e displacement of the lever L causes movement of the piston p within the power cylinder 0.

With such arrangements it is obvious that if the rodeo of the piston p is connected to the control of that which is to be controlled when any excess of speed beyond that predetermined talcs place due to disturbance of load Jfactor automatic control instantly ensues and all racing is prevented.

ln some cases when an abnormal increase of speed takes place or that which is to be controlled for some reason is temporarily unresponsive to normal governing action a trip device may be provided adapted to prevent return movement 'of the piston p after displacement of predetermined amount.

In Fig. l the upper part of the rod L0 is provided with a screw thread with which a collar fr is operatively engaged a pivoted detent y being provided to engage with the collar ai and maintain it in position if the travel of the rod w is sufhciently excessive. To enable the collar m and the detent y to be disengaged a pivoted lever z is provided.

l claim:

l. An improved governing device having in combination a pivoted lever continuously oscillated by theV apparatus the speed of which is to be controlled, a pivoted lever rigidly carrying a mass adapted to be oscillated by the first named lever through two oppositely disposed yielding resistances, a bifurcated pivoted lever having two abutments said bifurcated lever being adapted to be angularly displaced when the lever carrying the mass contacts with either of' the abutments, a source of motive fluid under constant pressure, a valve device mechanically associated with and operable by th-e bifurcated lever adapted to permit passage of motive fluid under pressure when the bifurcated lever is angularly displaced, a fluid pressure operated control device connected to the delivery from the valve device said control deviceacting against an increasing yieldingl resistance and returning to its initial posit-ion on interruption of the supply of fluid pressure.

2. ln an improved governing device as claimed in claim l the arrangement of a fluid pressure operated valve device comprising a cylinder, a piston in said cylinder, a spring for maintaining the piston in position against lthe fluid pressure, a transverse portway in said piston, a portway for cony Leeaiso ducting motive fluid under pressure to said transverse portvvay from said cylinder, ports in said cylinder so located that communication can be effected between said ports and the transverse portway in said piston to allow motive fluid to escape, an escape branch in the cylinder communicating Withsaid ports, a branch for admitting motive fluid under pressure into said cylinder and a branch for conducting motive fluid to a 10 fluid pressure operated control device.

In testimony whereof I have signed my name to this specilication.

` THOMAS JACKSON.

Images