US3072147A

US3072147A - Electro-pneumatic translator

Info

Publication number: US3072147A
Application number: US141657A
Authority: US
Inventors: Clifford W Allen; Homer A Knight
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1961-09-29
Filing date: 1961-09-29
Publication date: 1963-01-08
Anticipated expiration: 1980-01-08

Description

Jam 8, 1963 c. w. ALLEN ETAL 3,072,147

ELECTRO-Premium TRANsLAToR Filed Sept. 29, 1961 TO FLUID PRESSURE i OPERABLE DEVICE Il JNVENTORS CLIFFORD W. ALLEN BY HOMER A. KNIGHT QLLMLMM.

A WUHNE/ United States Patent Ghhce 3,072,147 Patented Jan. 8, 1963 3,072,147 ELECTRO-PNEUlt/IATIC TRANSLATR Cliiford W. Allen, Monroeville, and Homer A. Knight, Pittsburgh, Pa., assignors to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsyl- Vania Filed Sept. 29, 1961, Ser. No. 141,657 7 Claims. (Cl. 137-597) This invention relates to electro-pneumatic translators and, more specifically, to such a translator device characterized by a novel arrangement for proportioning the degree of fluid pressure delivered thereby to the degree of electrical energization of the translator device.

The present invention is particularly useful for apparatus characterized by both electrical and fluid pressure operable components which are functionally interrelated. The principal object of the present invention is to translate variations of an electrical characteristic into corresponding iluid pressure variations for control purposes.

Accordingly, the invention comprises an electro-pneumatic translator device having a main passageway, through which a main stream of compressed air ows from an inlet port to a delivery port, and an atmospheric branch passageway through which a portion of the main stream may be deected in varying degrees according to the force exerted by a transverse stream of air directed against the main air stream. A solenoid-operated plunger controls the force of the transverse stream of air on the main stream of air by varying the degree of unbalance in venting of opposite ends of a passageway which intersects the main passageway and in which vacuum or subatmospheric pressure is created by flow of the main air stream therepast. The one end of the intersecting passageway is constantly open to atmosphere and the degree of venting of the other end of the intersecting passageway is determined by the position of the plunger which, in turn, is determined by the degree of electrical current energizing the solenoid.

Although the invention may be employed with either hydraulic or pneumatic iiuid systems, it will be considered, in the following detailed description, in connection with pneumatic fluid or compressed air.

in the drawing, FlG. l is a diagrammatic View, in section, of an electro-pneumatic translator embodying the invention, and FIG. 2 is a sectional view, taken along line 2 2 of FIG. l in the direction indicated by the arrows.

Description and Operation The electro-pneumatic translator, 'as shown in FIG. l, comprises a solenoid-operated plunger device 1 and a iiuid pressure control portion Z.

The uid control portion 2 comprises a casing section 3 provided with an inlet port 4, which is connected to a reservoir 5 charged with compressed air, and a delivery port 6 connected to a iluid pressure operable device such as a relay valve device 7. The relay valve device 7, in wellknown manner, operates responsively to the degree of compressed air supplied to a control chamber therein from the delivery port 6 to effect delivery of pressure iluid from reservoir 5 to a iiuid pressure operable device (not shown) at a pressure bearing a predetermined ratio to the pressure in the control chamber. The inlet port 4 is connected to the delivery port 6 by a main passageway ii formed in casing section 3, while a branch passageway 9 diverges from said main passageway at an angle less than 90 relative to the direction of iiow of pressure fluid through said main passageway to thereby place said main passageway in communication with atmosphere and permit divergent flow therefrom to atmosphere. A passageway 10 intersects the main passageway 8 at a point between the inlet port 4 and the divergency of branch passageway 9 from said main passageway, said point of intersection being in the proximity of said divergency. One end of passageway 10 opens to atmosphere while the other end opens to a chamber 11, hereinafter called the vacuum chamber.

The solenoid-operated plunger device 1 comprises a casing section 12 attached to casing section 3 in suitable manner not shown and having therein a solenoid winding 13 provided with

conductors

14 and 15 by which the solenoid may be energized and deenergized for eifecting operation of a core or plunger 16. The plunger 16 has associated therewith a coaxially disposed valve member i7 extending from said plunger into an axially aligned bore 18 formed in casing 3. and connecting with vacuum chamber 11, said valve member being axially operable within said bore with a substantially air-tight iit relative thereto. The valve member 17 is provided with a groove 19 extending longitudinally over a portion of the length of said valve member, said groove opening at one end to the vacuum chamber 11.

The plunger 16 is biased by a spring 20 toward and occupies a normal position, when the solenoid winding 13 is deenergized, in abutment with an annular stop member 21 iixed in casing 12, in which normal position the valve member 17 occupies a cut-olf position in which the end of groove 19 in said valve member opposite the end opening into vacuum chamber 11 is sealed off from an atmospheric chamber 22 formed in said casing and open to atmosphere r via a passageway 23 also formed in said casing. The

plunger 16 and, therefore, valve member 17 are axially movable responsively to energization of solenoid winding 11 in a left-hand direction, as viewed in the drawing, and against the opposing force of spring 2li, the amount of such movement corresponding to the amount of current with which the solenoid winding 13 is energized. If sufiiciently energized, solenoid winding 13 effects movement of plunger 16 and valve member 17 to respective vent positions in which the end of groove 19 opposite vacuum chamber 11 clears bore 1S to establish communication, via said groove, between said vacuum chamber and atmosphere by way of atmospheric chamber 22 and passageway 23. It is significant to note, for a purpose to be hereinafter more fully explained, that groove 19 is tapered between its ends so as to provide a progressively larger opening at the point of clearance with bore 18, indicated by the reference character C in the drawing, as the valve member 17 is moved out of said bore by the plunger 16.

in considering the operation of the electro-pneumatic translator above described, let it be assumed that the winding 13 of the solenoid-plunger device 1 is deenergized and that valve member 17, therefore, is in its cut-olf position. Let it further ybe assumed that compressed air is owing in the directio-n indicated by the arrows, from the reservoir 5 to the control chamber of the relay valve device 7 via inlet port 4, main passageway 3 and delivery port 6. As above noted, the pressure of iluid delivery eifected by the relay valve device 7 to the iiuid pressure operable device (not shown) is in ratio with the pressure of air supplied to the control chamber of said relay valve device. With valve member 17 in its cut-olf position, vacuum chamber 11 is sealed off from atmosphere so that thejet stream caused by dow of compressed air through main passageway 8 and through the intersection of said main passageway with the intersecting passageway 10, creates a partial vacuum in said vacuum chamber. With the partial vacuum in chamber 11 and with atmospheric pressure entering from the right side of the intersecting passageway 10, as viewed in the drawing, a pressure differential lis thus created to set up a cross stream in said intersecting passageway to act on and thereby deflect a portion of the main jet stream flow from main passageway 8 to branch passageway 9 from whence it escapes to atmosphere. TA us, only a portion of the compressed air entering inlet port 4 reaches the control chamber of the relay valve device 7' which thereby func-- tions according to the degree of air pressure resulting in said contro-l chamber.

lf the Winding i3 is energized sufficiently, as by a rheostat 24, to cause the end of groove 19 to clear point C, chamber 1f. is thus vented to atmosphere to a degree corresponding to the size of the opening provided by said groove at point C as determined by the point of said groove registering with point C. it should be understood that since the relationship between the energizing current for winding 13 and the amount of resulting movement of plunger l may not be in the nature of a linear proportionality, the groove 17 may be so designed as to compensate for such deviation and thereby provide for a linear ratio between the electrical input at the winding 13 and the air pressure supply to the relay valve device 7. In accordance with the degree of venting of vacuum chamber 11, the pressure dierential between the two ends of intersecting passageway fr is reduced and therefore the amount of deflection of the main ,iet stream through main passageway is accordingly reduced, the net effect of which is an increase in the pressure of compressed air resulting in the control chamber of the relay valve device 7. it should be evident, therefore, that the electro-pneumatic translator may be designed such that maximum energization of the solenoid winding 13 will produce suiilcient movement of the plunger to and valve 17 to effect complete atmospheric venting of chamber 11. With chamber ill; completely vented to atmosphere, venting of intersecting passageway il@ is balanced at both ends thereof to thereby eiiect delivery of maximum pressure of compressed air to the control chamber of the relay valve device 7 and consequently delivery of fluid at maximum pressure to the fluid pressure operable device.

Having now described the invention, what we claim new and desire to secure by Letters Patent is:

l. An electro-pneumatic translator device comprising a Casing having a through passageway therein at one end of which is a fluid pressure inlet and at the opposite cud of which is a fluid pressure outlet, a transverse passageway intersecting said through passageway and in which a sub-at nospheric pressure is created by iiuid pressure flow in the through passageway, one end of said transverse passageway on one side of said through passageway being open to atmosphere, valve means in the other portion of. said transverse passageway on the opposite side of said through passageway for varying the degree of opening of the other portion of the transverse passageway to atmosphere thereby to vary the differential pressure in the portions of the transverse passageway on opposite sides of the through passageway to effect a transverse force deflecting the iiuid flow in the through passage, and a branch passageway opening out of said through passageway into which a portion of the iiuid flowing in the through passageway may be deiected, the pressure of the Huid delivered at said outlet varying according to the position of said Valve means.v

2. An electro-pneumatic translator device as defined in claim l, .urther characterized by electro-responsive means energizable in Varying degree to correspondingly operate said valve means to different positions thereby to control the fluid pressure delivered at said outlet in accordance with the degree of energization of said electroresponsive means.

3. The combination as defined in claim 2 wherein said electro-responsive means comprises a plunger carrying said valve means for operating the same, said plunger having a normalposition in which said valve means occupies a cut-off position for completely cutting oif the other portion of said transverse passageway from atmosphere, a spring for biasing said plunger' in one direction toward its said normal position, and a solenoid effective,v when energized, for causing movement of said plunger, in a direction opposite to said one direction, and therefore operation of said valve for venting said chamber to atmosphere, the amount of such movement of said plunger' and, therefore, the degree of venting of the other portion of said transverse passageway being commensurate with the degree of said energization of said solenoid.

4. An electro-pneumatic translator device as defined in claim 2, further characterized in that said branch passage-- way diverges from said main passageway at an angle less than relative to the direction of flow of said main pressure iiuid stream.

5. An electro-pneumatic translator device as dened in claim 2 further characterized in that said transverse passageway intersects said through passageway at a point between the inlet of said through passageway yand the connection thereof with said branch passageway, said point of intersection being in the proximity of said connection of said branch passageway with said through passageway.

6. An electro-pneumatic translator device as deiined in claim l wherein said valve means is further characterized by a tapered groove formed therein and providing said opening through which the degree of venting of the other portion of said transverse passageway to atmosphere may be gradiently controlled in accordance with the amount of movement of said valve means.

7. An electro-pneumatic translator device for proportioning the degree of fluid pressure delivered to a fluid pressure responsive device from a source of fluid under pressure, according to the degree of electrical energization of said translator device, said translator device comprising, in combination, a casing having a main passageway through which a main pressure uid stream may liowV from the source to the fluid pressure responsive device, a branch passageway having one end connecting with said main passageway and leading therefrom to atmosphere, and an intersecting passageway intersecting said main passageway, said intersecting passageway having one end open to Vatmospheric pressure and the other end open to a chamber which may be gradiently vented to atmosphere and in which vacuum or sub-atmospheric pressure is created by iiow of said main pressure fluid stream through said main passageway, the degree of said vacuum being inversely proportional to the degree of said venting of said chamber, whereby a transverse stream of air is caused to iiow through said intersecting passageway from said one end open to atmosphere toward said vacuum in said chamber and thereby be directed against said stream of pressure fluid in said main passageway for deliecting a portion of said main pressure fluid stream into said branch passageway proportionately to the `force of said transverse air stream acting on said main pressure fluid stream; valve means interposed between said chamber and an atmospheric passageway formed in said casing for controlling graduated venting of said chamber to atmosphere, and therefore the vacuum created therein accordingly, for reducing or increasing the deflecting effect of said transverse stream on said main pressure fluid stream according to the degree of venting of said chamber via said atmospheric passageway; and Yelectro-responsive means operable responsively to variable degrees of electrical energization thereof `for effecting a corresponding amount of movement of said valve means, and therefore a corresponding degree of venting of said chamber, according to the degree of electrical energization actuating said electrical means.

Hurvitz Sept. 26, 196i Hausmann Jan. 9, 1962

Claims

1. AN ELECTRO-PNEUMATIC TRANSLATOR DEVICE COMPRISING A CASING HAVING A THROUGH PASSAGEWAY THEREIN AT ONE END OF WHICH IS A FLUID PRESSURE INLET AND AT THE OPPOSITE END OF WHICH IS A FLUID PRESSURE OUTLET, A TRANSVERSE PASSAGEWAY INTERSECTING SAID THROUGH PASSAGEWAY AND IN WHICH A SUB-ATMOSPHERIC PRESSURE IS CREATED BY FLUID PRESSURE FLOW IN THE THROUGH PASSAGEWAY, ONE END OF SAID TRANSVERSE PASSAGEWAY ON ONE SIDE OF SAID THROUGH PASSAGEWAY BEING OPEN TO ATMOSPHERE, VALVE MEANS IN THE OTHER PORTION OF SAID TRANSVERSE PASSAGEWAY ON THE OPPOSITE SIDE OF SAID THROUGH PASSAGEWAY FOR VARYING THE DEGREE OF OPENING OF THE OTHER PORTION OF THE TRANSVERSE PASSAGEWAY TO ATMOSPHERE THEREBY TO VARY THE DIFFERENTIAL PRESSURE IN THE PORTIONS OF THE TRANSVERSE PASSAGEWAY ON OPPOSITE SIDES OF THE THROUGH PASSAGEWAY TO EFFECT A TRANSVERSE FORCE DEFLECTING THE FLUID FLOW IN THE THROUGH PASSAGE, AND A BRANCH PASSAGEWAY OPENING OUT OF SAID THROUGH PASSAGEWAY INTO WHICH A PORTION OF THE FLUID FLOWING IN THE THROUGH PASSAGEWAY MAY BE DEFLECTED, THE PRESSURE OF THE FLUID DELIVERED AT SAID OUTLET VARYING ACCORDING TO THE POSITION OF SAID VALVE MEANS.