US1658577A - Regulator - Google Patents

Description

Feb. 7, 1928.

C. H. SMOOT REGULATOR Filed March 7. 1927 llllllllllllll INVENTOR (gyrij ///WOOT' BY vn ATTORNEYS Patented, Fa.. 7, 1928.?

CHARLES H. SHOOT, 0F MAYPIJEWOD, NEW JERSEY.

REGULATOR.

Application led March 7, 1927. Serial N0. 173,226.

My invention is concerned with a novel regulator so constructed as to avoid huntlng without loss of sensitiveness or power.

My regulator is of the type whereln an unbalance between. a regulating/force or forces and avforce'varying with a function of the element controlled effects the regulation of an element through an intermediate power means. My invention comprises electrical power means actuated upon an unbalance of regulating and regulated forces for effecting the control of the element and for preventing hunting of the regulator.

ForV an understanding of my invention, reference should be had to the accompanying drawings of which Fig. 1 illustrates one embodiment of my regulator as applied to the control of a fluid pressure, and i Fig. 2 illustrates an alternative arrangement of a part of the apparatus shown in Fig. 1.

Referring now to Fig. l, a damper 1' effects the control of the ow of fluid through a conduit 2. The damper is oper-l ated to maintain a constant fluid pressure atsome point in the fiow and is adjusted toOthe position corresponding to the desired pressure by a reversible electric motor 3 which turns the damper in either direction by means of rack 4 and worm gear 5 mounted on the shaft 6 of the motor. One terminal of the motor 3 is connected by means of a lead wire 7 with a power circuit at 8. The other terminalsofthe motor lead to contacts 9 and 10 arranged on either side of a contact 11 carriedby a pivoted lever 13 and connected through lead wire 12 to the other side of the power circuit at 8. The lever 13 carries an adjustable weight 14 tending to turn the lever in a counter clockwise direction. Opposed to the turning moment offered by the weight 14 to the lever 13 is a moment duc to th pressure of the fluid in the conduit 2 acting through a pressure bell 15 attached to the lever 13 and partially submerged in liquid, the space enclosedbetween the bell and the liquid being in communication with the conduit 2 through pipe 16.

The apparatus so far described would operate to regulate the fiuid in the conduit 2 for constant pressure, but only with continual hunting of the damper. If the pressure of the uid rises to a value greater than y28 is screwed over the that for which the re ulator is adjusted, the pressure within the gell 15 overpowers the effect of the weight 14 and tips the lever, thereby closing contacts 9 and 11 and energizmg the motor 3 to close the damper 1. As long as the pressure within the bell is greater than that desired the motor 3 will continue to close the damper. By the time the reduction in pressure caused by the closlng of the damper is felt at the lever the damper has been still further closed. This results in a too low value of the pressure in the bell and an energizing of the motor 3 b contacts 10 and 11 driving the motor in the reverse direction and to a position too far open.

The apparatus now to be described prevents this oscillation of the damper. A rod 17 1s shdably mounted in fixed bearings 18 and is provided end in which the head 19 of a second rod 20 i s free to turn. The rod 17 carries projections 21v to which are attached springs 22. The springs 22 are fastened to the end of the lever 13, the arrangement being such that with the normal position of the rod 17 and neutral position of the lever 13 the springs 22 exert no force upon the lever 13. The rod 17 carries a contact arm 23 connected through lead wire 24 with the power circuit at 8 and arranged to travel over fixed contacts 2,5 and 26 with upward and downward movement respectively of the rod 17. The rod 20 is threaded throughout its lower half and provided with longitudinal slots 27.a1ong its upper half. A member the rod 2O and is supported in a fixed bearing 29 in which it is :tree to turn but not to travel vertically. A gear 30 forming a part of the member 28 meshes with a gear 3l on the shaft of a reversible electric motor 32, which motor is connected in parallel with threaded portion ofwith a socket in its lower the motor 3 and is therefore actuated wheni ever the motor 3 is actuated. The up er half of the rod 2O passes through a member 33 to which it is keyed by means of longitu' dinal ridges on the inner side of the member which fit into the slots 27. The member 33 is mounted inl fixed bearings 34 in which it is free to turn but not to move vertically. A gear 35 forms a part of the member 33 and meshes with a gear 36 driven by a third reversible electric motor 37, one terminal of which is connected through lead wire 38 with the power circuit'at 8 and the other termlnals vof which are connected tothe stationary contacts 25 and 26.

The arrangement ot' the motors 32 and 37 with the rod 20 is such that either motor can raise or lower the rods, and if both motors are operating at the same time the travel of the rod will be either the sum or diiference of thetravels that would be caused by either motor alone, depending upon whether the motors are aiding or opposing each other. yits shown, the gear 30 has a smaller\ diameter than the gear 35 and correspondingly fewer teeth with the result that with equal speeds of the motors, the rod will travel more rapidly with the motor 32 than with the motor 37.

The operation of the entire apparatus disclosed in Fig. 1 is as follows: `With aV steady flow through the conduit- 2 and a pressure in the bell 15 just suiicient to maintain the lever in the neutral position, the motors 3, 32 and 37 will not be operating because the contact 11 will not be touching either of thecontacts 9 or 10 and the contact 23 will not be touching either of the contacts 25 or 26. Assume now that the pressure in the conduit 2 and therefore in the bell 15 rises. This causes the contacts 11 and 9 to close and the motors 3 and 32 to operate simultaneously, the one to close the damper, the other to raise the rods 2U and 17. The raising of the rods 20 and 17 applies a resilient force to the lever 13 through the compression of the lower spring 22 and the tension of the upper spring tending to open the contacts 11 and 9. It the increase in pressure in bell 15 was very great the motor 32 may have to raise the rods 17 and 20 very considerably before exerting enough force upon the lever to break the contacts and so to stop both motors 3 and 32. As soon as the rod 17 has been raised 1sufficiently to close the contacts 23 and 25 the motor 37 starts to turn the member 33 in a direction to lower the rods 20v and 17. While both the motors operate at once the motor 37 acts to slow up the travel of the rods, but as soon as the force exerted by the springs 22 is sufficient to break the electrical circuit through the lever, the rod begins to be slowly lowered by the motor 37 which thus gradually releases the force upon the lever due to the springs 22. The speeds of the motors or the size of the gears are preferably so chosen that the tlme taken for a change in the setting of the damper 1 to be felt as a pressure change in the bell 15 will correspond to that taken by the motor 37 to release the tension of the springs upon the lever 13.

With a decrease in pressure within the bell 15 the operation is of course just the reverse of that described above. The contacts 1() and 11 close energizing motors 3 and. 32, causing them to operate in the reverse dlrection to that when contacts 9 and 11 are closed and resulting in an opening ot the damper and a lowering of the rods. The tension of the springs upon the lever is thus increased until it becomes sufficient to open the contacts and to stop the motors. The motor 37 actuated when the rod was lowered gradually returns the apparatus to the neutral position. Y

It the` damper has not been moved far enough by the time the motors' 3 and 32 are stopped, then these motors will again be energized as soon as the tension of the spring 22 has been sutiiciently reduced.

Fig. 2 illustrates a slightly dierent arrangement of lever, springs and contacts. In this arrangement the springs 22 are not carried by the rod 17 but are xed at their ends to stationary members 21', and the contacts 9 and 10 are carried by the rod 17 instead of being fixed.

The operation ot' each arrangement is the same in that aclosing of the contacts 11 and 9 or 11 and 1() results in a movement of the rod tending to open` the contacts and to increase the tension of the springs upon the lever. In the embodiment of Fig. 1 this is accomplished by an upward movement of the rod when the .contacts 9 and-11 are closed and by a downward movement of the rod when the contacts 10 and 11 are closed. In Fig. 2 this vis accomplished by just the reverse movement of the rod 17, that is, a downward movement when the contacts 9 and 11 close and an upward movement when the contacts 10 and 11 close. In each arrangement the closing of the contacts 23 and 25 or 23 and 26 results in a movement of the rod 17 in a direction to return it to the position from which it has been moved.

I have now illustrated' onel embodiment ot' my invention and an alternative arrangement of a part thereof. For convenience I have shown my new regulator arranged to maintain constant the pressure of. a i'luid by the control of a damper. Obviously my in vention is not concerned with the particular element controlled nor with the controlling force or forces which in' the particular case illustrated was a constant, being the value introduced by the position of the weight 1l upon the lever. Obviously this weight can be replaced with any desired fixed or varying force or forces without affecting my inventi'on. The particular 'means herein shown for acting on the lever with a force varying as a function of the element controlled is et' course immaterial, as any desired means may' be used.

Although I have shown the damper 1 and member 23 driven by Separate motors, it obviously would not change the operation ot' my regulator if both ot these elements were driven by the same motor.

Two motors, however,

step is not sufficient it makes a further corupon the rection. The length of any step depends actual magnitude of the change in the element and also upon duration of this change. A momentary increase or decrease in pressure, no matter how large, results in a very small movement of the damper and an immediate return to t-he original setting while a large permanent change results in a n large movement of the damper before the Y and itself, and additional motor is stopped.

Obviously many substitutions and rearrangements of parts may be made without departing from the scope of my invention and parts of my apparatus may be advantageously employed without the corresponding use of other parts.

I claim:

l. In a regulating apparat-us of the type wherein an unbalance between a regulating force and a force varying as a function of the element controlled effects the control of an element through auxiliary electrical power means, the improvement consisting in electrical means actuated simultaneously with said power` means, for creating. a gradually 1n creasing resilient force tending to stop both said power means and itself from functioning 4and additional electrical means actuated when said resilient force reaches a definite value tending to reduce said force.

2. In a regulator of the type wherein an imbalance between a regulated force and a force varying as a function of the element controlled effects the control of an element through auxiliary power means,l the improvement consisting in electrical means Yactuated simultaneously with said power means for creitin a gradually increasing resilient force tending to prevent the continued operation of both said power means slower acting means tending to reduce and remove said resilient. force.

3. In a regulator of the type in which a regulating force opposes a force which is a function of the regulated element, the combination comprising a reversing switch, the movable member of which is subjected to said opposing forces and is 'normally acted upon in open position by equal opposing resilient forces, electric means actuated by closure of said switch upon an unbalance of Atending to the forces acting upon said movable member, and operating to produce a regulating effect and to cause an unbalance of said resilient forces progressively increasing until suliicient to open said switch, andv other electric means brought into operation at a given vunbalance of to restore the normal balance thereof.

4. In a regulating apparatus the combination of a controlling means, a movable member acted upon by a regulating force and by a force varying as a function of the element to be controlled, an electric motor for operating said controlling means, means for driving said motor in one direction with a' displacement of said member in one direction and for reversing said motor with a displacement of said member in the other direction, springs tending to hold said member in a neutral position, means for increasing continuously the force exerted on said member by said springs during continued operation of said motor, other means operating to return the force of said springs to zero and started into operation when the force of said springs has reached a predetermined value.

5..In` a regulator of the type wherein a regulating force opposes a force which is a function of the regulated element, the combination comprising a reversing switch, theA movable member of which is subjected to said opposing forces and -is maintained in open position by a balance thereof, a second movable member, electric means actuated by closure of said switch under an unbalance of said forces, and operating to effect the regulation and to move said second member,

the resilient forces and acting I means for creating a force increasing with the displacement of said second member and reopen the switclnand lmeans, actuated v upon a definite displacement of said second member tending to return it to its original position and tending likewise to reduce and remove said last mentioned force.

6. In a regulator of the type wherein an unbalance betweenga regulating force and a regulated force varying as a function of the element'controlled effects the control of an element through intermediate powermeans,

the improvement'. consisting in a longitudinally movablemember 'and electric means including at least one reversible electric motor -for moving said member andfor effecting the regulation of the element, means for actuating said motor upon an imbalance of regulating and regulated forces, means carried by said member tending upon continued movement thereof to stop the operation of said electric means, another reversible electric motor for returning said member to its original position and means carried by said member for actuating said last named motor.

7. ,Apparatus as in claim wherein said longitudinally movable member consists of tW o parts', one carrying the means for actuating said second motor and being adapted to be moved vertically by the other part but tuatediby the closure of said switch for efectingl`v` the regulation and for creating a force'.increasing with the duration of the closure o:t tlre switch and acting upon said member in a direction to open the switch, sloweracting apparatus tending to relieve said member of said last mentioned force, means for bringing said apparatus into operation after said switch has been closed for a definite time, and for continuing it in operation until said member is relieved of said last mentioned force.

In testimony whereof, I have signedrhy name to this specification.

CHARLES H. sMooT.

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