US1141975A - Pneumatic controller. - Google Patents

Description

L. OSBORNE.

PNEUMATIC CONTROLLER. v APPLICATION FILED APR. 8. 1914.

Patented June 8, 1915.

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V UNITED STATES PATEnT OFFICE.

J'OHN I OSBORNE, OF ROCHESTER, NEW YORK, ASSIG-EIOR T0 JUDSON GOVERNOR COMPANY, OF ROCHESTER, NEW YORK, A CORPSEJATION OF NEW YOIfiK.

PNEUMATIC CONTROLLER.

To all 1.0 7mm it may concern Be it known that 1, JOHN L, OSBORN'Eh-fi. citizen 'of the UnitedStates, and resident of Rochester, in the county of 'Monroe and State of New York, have invented certain new and useful Improvements in Pneumatic Controllers, of which the following is a specification.

mechanism, chntrolled by air-pressure or this vent bein otherwise, arranged to open and close a feed-passage through which compressed air or other motive-fluid is admitted to the motor, and the air so admitted is thereafter discharged from the motor through an ex haust-port orvent which is constantly open,-

rcstricted to a size sufii-' ciently large to exhaust the air from the motor with the required rapidity, when the feed-passage is closed, but not large enough to prevent the operation of the motor when the feed-passage is open.

The use of a constantly open exhaustport, as above described, involves a constant escape and waste of motive-fluid, and one object 'of ,the present invention is to avoid this loss. To this end I have devised a valve-mechanism which will always auto maticaily close the exhaust-port before opening the feed-passage, and close the feed-passage before opening the exhaust-port, so that there is never direct communication between the feedpassage and'the eXhaust pQrt. In this mechanism I preferably employ only valves of the puppet type, in a form which permits them to be cheaply manufactured, and arranged in such a manner that they may be easily and accurately fitted to each other and that they tend always to seat themselves properly and avoid leakage when in use."

\ Another object oi the invention is to so construct and arrange the valve-members of the controller that its operation is abrupt, and-that there is a definite interval between the point at which the motor is thrown into operation, and the point at which it is thrown out of operation, and accordingly I so arrange the valve-mecllanism that when Patented June 8, 1915.

Application filed April 8, 1514. Serial No. 830,471.

the feed-passage is open the pressure of the motive-fluid is operable against a surface on one of the valve-members in a direction to hold this member in open position, while the pressure is excluded from this surface so when said valve-member is in the position in which the feed-passage is closed.

Other objects of the invention, and the features of construction and arrangement by which the several objects of the invention are attained, will be set forth in the following description of the preferred embodiment. of the invention.

In the accompanying drawings: Figure 1 is a verticalmedian section of a pneumatic controller embodying the present invention, and a motor and motor-controlled valve associated therewith; and Fig. 2 is a hori- 'zontal sectional view, on the line Q-2 in Fig. 1, looking upwardly, of the valvemechanism of-the controller.

In the illustrated embodiment of the invention the valve-mechanism of the controller is inclosed within a casing comprising upper and lower members 5 and 6, '0 threaded together as shown in Fig. 1. The casing is provided with an exhaust-port 7, through the member 5, discharging to atmosphere, and with an inlet-port constituting a part of the feed-passage to the motor, thisinlet-port being in the form of a longitudinalperforation 9 in valve-member 10.

The valve-mechanism comprises three distinct valve-members, of which the first is 0 embodied in, or integral with the casingmember 5, the second is embodied in the member 10, and'the third is embodied in a disklike member 11, which coiiperates with the other two valve-members and is pressed upwardly against them by means of a coiled spring 12. The first valvemember is fixed and is provided with an annular flat seat 13," which communicates, through an annular slot, with the exhaust-port 7 The second valve-member 10 is in the form of a stem arranged to fit closely but slide freely in the casing-member 5, and having an annular fiat seat at its lower end. This seat is disposed similarly to the seat- 13, that is to say,

ing contact with each of the two valve-seats, 11o

' v moved away from passage 9 and the into the upper end 1t until the member 11 ut between its middle portion and its periphery it is provided with openings 14 for the passage of air. The arrangement of the three valve-members is such that in the position of the parts shown in Fig. l the valvemember 11 is seated against the member 10, thus closing the passage 9, but is held away from the valve-seat 13, and at this time, therefore, the air is free to pass from the lower valve-casing member 6 through the valve-seat 13 to the exhaust-port 7, If the valve-member 9 be raised, however, the spring 12 will cause the member 11 to follow engages the valveseat 13, thus closing the exhaust-passage 9 still remains closed. It

however, this member is the valve-member 11, and a free passage is then provided between the port 8, by way of the 9 be continued,

open ngs 14.

The valvermeehanism just described is shown as connected with diaphragm mechanism by which it is actuated in accordance with variations in the pressure of the air which is admitted to the diaphragm-chamber and controlled by the valve-mechanism in its flow to the pneumatic motor. For this purpose the casing member 5 is screwed into the lower part 15 of a diaphragm-casing, the diaphragm 16 being clamped between the part 15 and an upper casing-member 17. The passage 9 in the valve-member 10 communicates, by a transverse passage 18, with the chamber below the diaphragm, and the upper end of this valve-member engages the diaphragm so as A spring 19, surrounding'the upper part of the valve-member l0 maintains it in en-- gagcment with the diaphragm and causes it to follow the upward movement of the latter.

'The diaphragm is normally held in depressed position by a counterbalancingspring 20 in the upper part of the diaphragm-casing, his spring cooperating with the diaphragm through a suitable follower 21, and being adjustable, in the usual manner, by means of a hollow screw 22. The spring 20 normally holds the valve-member 10 in its lowermost position, against the opposition of the springs 19 and 12,1but the diaphragmchamber may be connected, through an inlet-opening 23, with a source of supply of compressed air such, for exam: ple, as the receiver of an air-compressor.

While the controller above described may be employed in connection with-pneumatic motors for various purppses, I have illustrated it as employed in connection with the motor which controls the unloader-valve of an air-compressor. For this purpose the lower end of the casing-member 6 is screwed of a cylinder 24, in which to be controlled thereby.

a piston 25 is fitted, this cylinder and piston constituting a pneumatic-motor. constitutes also unloader-valve, since it cooperates with a valve-seat 26, which is clamped between the a lower end of the cylinder and a horizontal partition within a valve-body 27. Y valve-body has inletandoutlet- openings 28 and 29, respectively, and for use as an unloader-valve the outlet-opening 29 is connected with the intake-opening of the airpump of the compressor. The specific form of unloader-valve shown and described has certain n'ovel characteristics which are not claimed herein, as they may form the subject-matter of a separate application.

When the controller admits compressed air to the cylinder 2% the piston 25 is forced downwardly, against the opposition of a spring 37 within the valve-body, thus seating the lower end of the piston and closing the passage through the valve-body: When the air is exhausted from the motor by the operation of the controller the piston is raised by the spring 30, thus opening the unloader-valve.

Since there is no constant escape'of air justable valve 31, threaded into the projec' tion from the casing-member 5 through which the exhaust-port extends.

The operation of the mechanism asa whole is as follows: When. the compressor is in -operation the air-pressure beneath the diaphragm 16 gradually rises, as the pressure in the receiver rises, until it has reached the predetermined maximum pressure. spring 20 is so adjusted that when thispressure is reached the diaphragm is raised, permitting the spring 19 to raise the valvemember 10 until, the valve-member 11 engages the-valve-s'eat 13 and closes the exhaust-port. This seating of the valve 11 relieves the valve-member 10 of the pressure of the-spring 12, so that a very slight further increment of to cause the member 10 to move further. Upon this slight increment, however, the upward movement of the valve-member 10 is continued, thusdisengaging it from the 'valve member 11 and admitting compressed air, through the passages 18 and 9, the openings 14:, the lower part of the valve-casing 6, and. the port 8, to the pneumatic motor, and causing the unloader-valve to be closed. Upon the admission this manner to the space beneath the valve- -member 10, the pressln-e of this air becomes effective against the lower end of this valve- The pistonthe movable member of the The thus

This I of-compressed air in l member, so as further to balance the pressure of the spring 20 upon the diaphragm. Accordingly, the pressure at which the diaphragm will again be depressed, so as to move the valveanember 10 to its normal position, will be somewhat less than that by which the diaphragm was originally raised. From this it results that there is a distinct interval between the points of opening and closing of the feed-passage torthe pneumatic pressed air to the pneumatic motor, and

then, upon the further downward movement of the valve-member 10, the valve-member.

11 is carried with it, thus opening the exhaust-port and exhausting the air from the pnuematic motor, whereupon the unloadervalve is again opened. 7

It will be understood that the novel valvemechanism liereinbefore described as an element of the pneumatic controller may be controlled by means other than the diaphragm-mechanism shown, and that it may be embodied in various other forms within the nature of the invention as it is defined in the following claims.

I claim za 1. In a pneumatic controller, the combination of a valve-member provided with a valve-seat, a second valve-member movable relatively to the first and also aving a valve-seat, a third valve-member movable relatively to the first and secondandadapted to cooperate with both of said valve-seats, meanstending to hold the third valve-meniber in engagement with said seats, and means for moving the second valve-membe relatively to the first, whc by it is engagec with and disengaged iroin the-third valvemember, and also caused to move the latter v out of engagement with the first valvev 'member. 7

2. In a pneumatic controller, the combination of two concentrlc and relatively movable valve-members provided with similarlydisposed valve-seats, a third valve-member movable relatively to the first two and adapted to cooperate with both of said seats,

means tending to force the third valve-memher into engagement with the seats of the first two valve-members, and means for moving the inner one of the first two valve-members relatively to the others in a direction to cause it to engage and disengage the third valve-member, and to move the latter out of engagement with valve-members.

3. In a pneumatic controller, the combination, with a pneumatic motor, of a valvecasing communicating with said motor and provided with a feed-passage for conduct ing compressed motive-fluid to the motor, and an exhaust-port for discharging motive fluid therefrom; means actuated by variations in the presslire of the motive-fluid; and valvamembers cooperating with and =controlled said means, and controlling said feed-passage and exhaust-port, said means being adapted, upon the attainment of a predetermined pressure in the motive.

fluid, to first close the exhaust-port, and

- then open the feed-passage, and upon a drop in the pressure of the motive-fluid to a predetermined point, to first close the icedpassage and then open the exhaust-port.

4. In a pneumatic controller, the combination of a fixed valve-member havingan annular valve-seat and an exhaust-port terminating thereat, and having also a bore concentric with the valve-seat; a second valve-member in the form of a plunger movthe seat on the enter one of the first two' able in said bore, the second valve-member having a val ve-seat at the end adjacent the firstmentioned valve-seat, and a longitudinal passage terminating at said seat; a third valve'member having surfaces adapted to engage both of said valve-seats and having intermediate openings for the passage of fluid; resilient means tending to force the third valve-member into engagement with the valve-seats ,upon the other two Valvemembers; and means for actuating the second valve-member to cause it to move into and out of engagement with the third valvemember, and to cause the latter to be moved into and out of engagement with the valveseat on the first valve-member.

5. In a pneumatic controller, the combination of a fined valve-member having an annular valve-seat and an exhaust-port terminatin thereat, and having also a bore conceiit ic with the valve-seat; a second valve-member in the form of a plunger member having a valve-seat at the end adjacent the first-mentioned valve-seat, a pressure-sustaining surface, of substantial area surrounding its said valveseat, and a longitudinal passage terminating at said seat; a third valve-member having surfaces adapted to engage both oi said valve-seats and having intermediate openings for the passage of fluid; resilient means tending to force the third valve-member'into engagement; with the valve-seats upon the other two valve-members; and means for actuating the second valve-niember to-cause it to move into and out of engagement with the third valve-member, and to cause the latter to be moved into and out of engagement movable in said bore, the second valvevalve-seat, and a longitudinal passage terthird va'lve-memminating at said seat; a

bar in the form of a plate having surfaces adapted to engage both of said valve-seats and having intermediate openings for the passage of fluid; resilient means tending to force the third valve-member into engagement with the valv -seats upon the other two valve-members; and means for actuating the second valve-member to cause it to move into and out of engagement with the third valve-member, and to cause the latter to be moved into and out of,engagement with the valve-seat on the first valve-member.

.Witnesses:

FARNUM F. DORSEY, D. GURNEE.

JOHN L. OSBORNE. I

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