US3734117A

US3734117A - Fluid diaphragm modulator

Info

Publication number: US3734117A
Application number: US00090707A
Authority: US
Inventors: L Atkinson
Original assignee: Johnson Service Co
Current assignee: Johnson Service Co; Johnson Controls International Inc
Priority date: 1970-11-18
Filing date: 1970-11-18
Publication date: 1973-05-22
Anticipated expiration: 1990-05-22
Also published as: IT944963B; JPS524702B1; DE2156819B2; GB1376613A; NL7115891A; DE2156819A1; CA944277A

Abstract

A pair of spaced and series connected nozzles terminate in a first coupling chamber with a flat spring-loaded diaphragm forming an outer wall. A second coupling chamber closes the spaces between the nozzles. The diaphragm is a common wall with an input chamber. A main fluid supply is connected to either the first coupling chamber or to the first nozzle and an output or a reference pressure means is correspondingly connected to the second coupling chamber. A supply to the nozzle establishes aspiration between the two nozzles with a resulting negative pressure level. A control input signal to the input chamber moves the spring-loaded diaphragm toward the second nozzle with an increased pressure in the second chamber. Alternatively, the output is connected with the supply to the first chamber and the nozzles and second chamber are connected to references to establish unit gain and provide a repeater.

Description

United States Patent 1 1 1 3,734,117 Atkinson [4 May 22, 1973 [54] FLUID DIAPHRAGM MODULATOR Primary ExaminerAlan Cohan t L D. Atk N B l ,W [75] or mus mson cw er m ls Attorney-Andrus, Sceales, Starke & Sawall and Ar- [73] Assignee: Johnson Service Company, Milwauld J D A li kee, Wis. 22 Filed: Nov. 18,1970 [57] ABSTRACT A pair of spaced and series connected nozzles ter- [21] Appl' 90707 minate in a first coupling chamber with a flat springloaded diaphragm forming an outer wall. A second [52] US. Cl ..l37/82 coupling chamber closes the spaces between the noz- [51] Int. Cl ..G05d 16/00 zles. The diaphragm is a common wall with an input [58] Field of Search ..137/82, 83, 85, 81.5; chamber' A main fluid supply is connected to either the first coupling chamber or to the first nozzle and an output or a reference pressure means is cor- [56] References Cited respondingly connected to the second coupling chamber. A supply to the nozzle establishes aspiration UNITED STATES PATENTS between the two nozzles with a resulting negative 3,576,131 4/1971 Calderazzo ..73/37.5 pr re level. A control input signal to the input 3,250,116 5/1966 Hatch ...73/37.5 chamber moves the spring-loaded diaphragm toward 3,150,674 9/1964 C gh /8 the second nozzle with an increased pressure in the 3,461,896 Holloway second chamber Alternatively nhg output is on- 3,169,402 2/1965 Baker ....l37/85 X nected with the Supply to the first Chamber and the 3,566,899 3/1971 Bowditch ..l37/82 nozzles and second chamber are connected to FOREIGN PATENTS OR APPLICATIONS refetrences to establish unit gain and provide a reea er. 1,029,826 5/1966 Great Britain ..73/37.5 p

648,844 11/1962 ltaly ..l37/82 8 Claims, 6 Drawing Figures ZZ [4/8 i PATENTE M22 1875 inpyt FIGJ 4 L V///////F/ IOV wOutput FIG? INVEN Ton LOUIS D. ATKINSON Attorneys FLUID DIAPHRAGM MODULATOR BACKGROUND OF THE INVENTION This invention relates to a fluid diaphragm modulator or amplifier for producing a fluid control signal in response to an input fluid signal.

Diaphragm amplifiers are employed in the fluid control art to provide an isolated high power output fluid signal which is controlled by a relatively low power input signal. Generally, diaphragm amplifiers include a movable diaphragm unit defining an input chamber to one side of the diaphragm and a control or modulating chamber to the opposite side. The input pressure signal is applied to the input chamber to position the diaphragm with respect to one or more power stream ori fices.

The relative positioning of the diaphragm with respect to the orifices determines the output signal pressure and flow, thereby permitting control of a high pressure stream by a relatively low pressure signal. Diaphragm amplifiers may advantageously be designed with a high input impedance but are generally restricted to modulating between a first pressure level above a reference and a higher level.

SUMMARY OF THE PRESENT INVENTION The present invention is particularly directed to a diaphragm modulator permitting high gain with high input impedance, and establishing an output signal which may vary above and below a reference pressure and permit operation of the modulator as an amplifier or as a repeater with only a change in external tubing connections required. Generally, in accordance with the present invention, a pair of spaced and series connected nozzles terminate in a diaphragm-control unit and particularly a coupling chamber positioned at the discharge end of the stacked nozzles. The spacing between the nozzles is closed by a second coupling chamber providing a second connection to the fluid system. A control diaphragm forms at least a part of the wall of the coupling chamber, whichwall is opposed to the orifice of the second nozzle within the coupling chamber and thereby controls the effective opening of the orifice. The diaphragm is also a common wall with an input chamber of the diaphragm control unit. The diaphragm is resiliently loaded to a control position in spaced relation to the nozzle orifice.

A main fluid supply is connected to either the firs coupling chamber or the input nozzle and a control signal is connected to the signal input chamber. An output or a reference pressure means is correspondingly connected to the second coupling chamber.

With the supply connected to the first nozzle as an input, a fluid stream is established from the supply through the two nozzles into the first coupling chamber, which is also connected to a reference pressure. The stream establishes aspiration between the two nozzles with a resulting negative pressure level in the second coupling chamber which is connected to an output means. This permits reducing the output range below a zero pressure reference level. A control input signal to the input chamber moves the resiliently loaded diaphragm toward the orifice of the second nozzle, with the resulting increase in back pressure and actual diversion of the stream into the intermediate or second coupling chamber. The output pressure will thus rise from the aspirated level, with the pressure being proportional to input signal. When the diaphragm is forced by the input signal to completely cover the opposed orifice and close it off, a maximum output pressure is established in the second coupling chamber.

By connecting of a stream supply means and an output means to the first coupling chamber, and connecting the second coupling chamber and first or input nozzle to a reference or an exhaust, the apparatus functions as a fluid repeater. The pressure in the first coupling chamber will be directly related to the exhausting condition which is now controlled by the effective opening of the second nozzle orifice. Thus, with the input signal removed and the diaphragm wall means in the neutral position, the first coupling chamber is freely referenced to the respective nozzles.

As an input signal is established, the diaphragm wall moves toward the collector orifice, thereby restricting the passageway therefrom. This will increase the pressure in the first coupling chamber and therefore the output pressure until such time as the orifice is completely closed, at which time, the output pressure will be equal to the supply pressure.

The present invention thus provides an improved fluid amplifier which permits operation between negative and positive pressure levels, as well as maintaining high gain and high input impedance characteristics of the diaphragm amplifier.

DESCRIPTION OF THE DRAWING The drawing, furnished herewith, illustrates the preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will readily be understood from the following description.

In the drawing:

FIG. 1 is a vertical cross-sectional view of a diaphragm amplifier constructed in accordance with the present invention;

FIG. 2 is a plan view of the diaphragm amplifier shown in FIG. 1 with the several fluid supply and output connections diagrammatically illustrated;

FIG. 3 is a sectional view taken generally on line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken generally on line 4-4 of FIG. 2; a

FIG. 5 is a sectional view taken generally on line 5-5 of FIG. 1 to illustrate the preferred spring construction; and

FIG. 6 is a vertical section through a diaphragm amplifier constructed in accordance with the present invention and interconnected to fluid means to establish a fluid repeater.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing and, particularly, to FIGS. 1 and 2, a diaphragm amplifier unit 1, constructed in accordance with the teaching of the present invention, is illustrated having a first port 2 connected to a suitable pressurized fluid supply 3. The diaphragm unit 1 is particularly adapted for application in pneumatic systems wherein an air supply 3 is employed and the application is hereinafter described in connection with such a supply. Within the broadest aspects of the present invention, however, the device is equally applicable to other fluid supplies.

In the embodiment of FIGS. 1 and 2, a pair of

ports

4 and 5 are shown connected to a suitable pneumatic responsive output 6. The relative output pressure and flow is controlled by a pair of exhaust ports 7 and 8 connected to selectively vent the supply port 2 to a suitable reference 9, such as atmosphere. The proportionate exhausting or bleeding to reference is controlled by a diaphragm 10, the position of which is responsive to an input or control signal applied at a control port 11.

A suitable control signal source 12 is connected to the port 11 to variously position the diaphragm in accordance with the input signal pressure level. As more fully described hereinafter, the output pressure is directly related to the input signal pressure.

More particularly, the illustrated amplifier includes a base 13 having the upper wall thereof recessed to define with an intermediate ledge 14. The periphery of diaphragm 10 rests on a ledge 14 with a flat spring 15 disposed in overlying relationship upon the diaphragm. The ledge 14 is provided with a raised, clamping edge 16 to provide an essential line engagement with the diaphragm 10. An intermediate wall 17 includes a downwardly projecting angular wall 18, which telescopes into the recessed portion of the base 13 in alignment with the ledge 14. The intermediate wall 17 is secured to the base 13 in any suitable manner as by a pressed fit, positive interconnecting means or the like to clamp the inner face of the angular wall 18 against the peripherial portion of the spring 15, and thereby clamp the diaphragm l0 tightly against the edge 16 to establish a fluid-tight joint. This establishes an input chamber 19 between the diaphragm 10 and the base of the recess, which is interconnected to the input port 11.

As most clearly shown in FIG. 4, the underside of the base 13 is provided with a stepped recess to define a connecting port 20 between the chamber 19 and a capped chamber 21. The port 11 projects upwardly and outwardly from chamber 21 to provide an input signal to the sealed and dead-ended chamber 19, thereby producing the desirable high input impedance. The input signal establishes a fluid pressure tending to urge the diaphragm 10 and the spring member 15 upwardly of the chamber 19 and into the recess defined by intermediate wall 17.

The wall 17, as previously noted, includes the angular wall 18, which defines the first coupling chamber 22 between the other side of the diaphragm 10 and the base of the wall 17 within the angular wall 18. The intermediate wall 17 is provided with a nozzle 23 shown integrally formed therein. Nozzle 23 is generally coaxially located with respect to the

chambers

19 and 22. In the illustrated embodiment of the invention, the nozzle 23 projects downwardly into the chamber 22, terminating in slightly spaced relation to the flat spring 15 with the spring and diaphragm 10 in the neutral position. The nozzle 23 includes an orifice 24 of a preselected diameter.

The opposite side of the intermediate wall 17 is recessed in alignment with nozzle 23 to define a second coupling chamber 25, which is connected to the

output ports

4 and 5, in FIGS. 1 4, and having a concentric, conical portion 26 defining the supply means to the nozzle orifice 24. The chamber is closed by an outer wall, which includes the

output ports

4 and 5 communicating with the chamber 25. The wall 27 further includes a depending nozzle 28 aligned with the nozzle 23 and projecting downwardly into the conical recess 26. The nozzle 28 extends through wall 27 and includes a lower orifice 29 which is aligned with orifice 24 and having a cross-section somewhat smaller than the orifice 24. A top closure wall 30 is secured in overlying relationship to the wall 27 and includes a laterally extending channel 31 interconnected to the supply port 2 and to the nozzle 28 and establishing a fluid or air stream 32.

In the illustrated embodiment of the invention, the spring 15 includes a central lid portion 33 connected to an outer ring portion 34 by four identical equicircumferentially spaced arms 35. The lid 33 is shown as a square member. Each of the arms 35 is an L-shaped member, having one side parallel to and spaced from a corresponding side of the lid 33. The one end of each arm is connected to the corner of the lid 33 by an integral extension between the lid and the arm and the opposite end of the arm is similarly secured to the ring 34. The second arm portion of each arm is spaced outwardly from the first arm portion of an adjacent spring arm. The spring 15 is, thus, a flat disc-like spring with the arms 35 permitting essentially planar inward movement with respect to the orifice 24 in response to an input pressure signal in the chamber 19.

In the operation of the amplifier of FIGS. 1 4, supply to the port 2 initially establishes flow through the channel 31, the

nozzles

23 and 28 to establish a stream 32 into the chamber 22. The vent ports 7 and 8 connect to the chamber 22, exhaust the stream pressure and permit the stream flow. The diaphragm 10 is positioned when the forces of the input pressure signal in chamber 19 and the spring 15 equal the pressure of the stream 32 in chamber 22.

With a zero input signal in the input port 11, the spring 15 will assume the flat, neutral position, with the lid 33 spaced from the collector orifice 24. The supply 3 establishes the stream 32. As previously noted, orifice 29 is somewhat smaller than the orifice 24, and, consequently, the jet stream 32 will flow uniformly through the collector orifice 24. The free flow of the stream 32 will result in aspiration of fluid within the output chamber 25, thereby generating a relatively negative or vacuum pressure within the chamber 25. The corresponding pressure is, of course, established and transmitted to the output means 6 through the

output ports

4 and 5. The output range of the illustrated device is therefore at or below a selected zero reference.

Application of a positive input signal from the control signal source 12 through the port 11 creates a corresponding input pressure in the chamber 19. As the input pressure increases, the force of the spring 15 and particularly arms 35 is overcome and the diaphragm 10 forces the spring and particularly lid 33 outwardly of the chamber 19. As the lid 33 approaches the collector orifice 24, it opposes the free flow of the jet stream 32, thereby effectively reducing the orifice opening and diverting the flow of the stream 32 into the space between the

nozzles

28 and 23, resulting in a pressure in the chamber 25 and thus in the

output ports

4 and 5. The output pressure rises from the negative level to a positive level and is essentially proportional to the input pressure until the lid 33 seats against the underside of the orifice 24. The latter condition effectively closes the collector orifice 24 and thereby establishes a maximum output pressure in chamber 25.

The diaphragm amplifier 1 provides a high gain characteristic with the high input impedance, as a result of the dead-ending of the input signal into a closed chamber 19. Further, the dual nozzle construction permits the creation of a relatively negative pressure and thereby permits operation of the amplifier between a positive and a negative pressure and flow range with a proportional output signal.

Alternatively, the illustrated device is adapted for application to a fluid repeater wherein the output pressure is maintained equal to the input pressure over a selected range, while maintaining the high input impedance characteristic. The connection of the apparatus as a fluid repeater is diagrammatically illustrated in FIG. 6. The structure shown in FIG. 6 has been modified to relocate the ports to clearly illustrate the interconnection of the apparatus in a single view and it will be obvious that the apparatus of the previous embodiment can be similarly connectedto function as a repeater.

Referring particularly to FIG. 6, a recessed base 36, with a diaphragm 37 and a spring 38 mounted within the recess in the same manner as shown in the previous embodiment, appears therein. An input port 39 is similarly connected to an input chamber 40 defined by the diaphragm 37. An inverted cup-shaped closure wall 41 is telescoped into the recessed base 36 and abuts the spring 38 to provide a fluid-tight seal at the periphery of the diaphragm 37 and spring 38. An intermediate wall 42 is suitably secure in fluid-tight engagement within the cup-shaped wall 41 and with the underside of the wall 42 spaced outwardly from the spring 38 to define a coupling chamber 43, similar to chamber 22 of the previous embodiment. The wall 42 includes a connector nozzle 44 concentrically located with respect to the diaphragm 37 and spring 38. The backside of the wall 42 is recessed to define a chamber 45 overlying and extending laterally of the nozzle 44. The closure wall 41 includes a nozzle 46 aligned with the nozzle 44 to provide a pair of stacked and spaced nozzles with the space therebetween closed by the chamber 45. A port 47 is connected to the nozzle 46 and a port 48 is connected to the chamber 45. With the device applied as a repeater the

ports

47 and 48 are connected to a reference or vent rather than to a pressurized supply and a main power stream port 49 is connected to the chamber 43. The port 49 is connected to a pressured supply 50 through a pressure-dropping or coupling restrictor 51. In the illustrated embodiment of the invention, an output port 52 is also connected directly to the chamber 43 and to a first output means 53. A second output means 54 is connected to the downstream side of restrictor 51. Thus, in the embodiment of FIG. 6, as applied to the previous embodiment, the two vent ports 7 and 8 (FIGS. 1 4), respectively, become supply port 49 and an output port 52 and the supply port 2 and

output ports

4 and 5 of such first embodiment (FIGS. 1 4) are connected to atmosphere or reference.

In the embodiment of FIG. 6, a zero input signal at port 39 places the diaphragm 37 and the spring 38 in the neutral position, allowing relatively free venting of the chamber 43 to the chamber 45 and thus port 48 and also through nozzle 46 to port 47. The chamber 43 will thus assume the reference pressure and provide a corresponding minimal output pressure at ports 49 and 52.

As an input signal is applied via the port 39, the pressure in the chamber causes the diaphragm 37 and the spring 38 to deflect outwardly toward the nozzle 44. This, in turn, will reduce the venting via the nozzle 44 and tend to increase the pressure in chamber 43. The increase in pressure in chamber 43, however, will build-up and tend to oppose the input pressure in chamber 40. It will reach a balanced position only when the pressure in chamber 43 equals the pressure in chamber 40. Consequently, the pressure in chamber 43 and that appearing in the ports 49 and 52 will correspond to the pressure appearing in the input port 39 and the output pressure will thus equal the input pressure. This balanced arrangement is maintained for all of the pressures within the capability of the system. Thus, if the input pressure at port 39 should ever rise above the maximum available pressure via the restric tor 51, the spring 38 will engage the nozzle 44 and the output pressure will then be equal to the maximum pressure available. It cannot, of course, increase above such pressure, even should the input pressure signal increase further.

The output pressure will thus equal the signal input pressure, as long as the input pressure does not rise above the maximum available pressure available at the I downstream side of restrictor 51.

The present invention thus provides very simple, reliable diaphragm amplifiers which can be employed in various configurations to provide a proportional high gain amplifier with a high input impedance and alterna tively a repeater having a one-to-one gain while maintaining or retaining the high input impedance characteristic.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims, particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. A fluid diaphragm modulator comprising a chamber means including a diaphragm wall means common to a first coupling chamber and a signal chamber, an input signal means connected to said signal chamber for selectively positioning said diaphragm wall means, a first orifice means in said coupling chamber in aligned opposed relation to said diaphragm wall means, a second orifice means mounted in spaced aligned relation to said first orifice means outwardly of said coupling chamber, said first orifice means being larger than said second orifice means and being closely spaced whereby a stream emitted from said second orifice means and passing freely through said first orifice means aspirates fluid, a second coupling chamber means enclosing the space between said first and second orifice means, a pressurized fluid supply means connected to said second orifice means and a fluid reference means connected to said first coupling chamber whereby a continuous stream is established through said orifice means with said diaphragm spaced from said first orifice means, and a load means connected to said second cou pling chamber for providing in response to said input signal an output signal at said second coupling chamber varying from an aspirating condition to said supply means pressure in accordance with the position of said diaphragm wall relative to said first orifice means.

2. The fluid diaphragm modulator of claim 1 wherein said orifice means are essentially coaxial.

3. The fluid diaphragm modulator of claim 1 wherein said diaphragm wall includes a flat diaphragm secured about the periphery within said chamber means in opposed relation to said first orifice means, a flat spring means overlying said diaphragm within said chamber and secured at the periphery, said spring means having a central portion movable linearly relative to the plane of said diaphragm, and said fluid signal chamber uniformly applying a pressure over the backside of the diaphragm to selectively move the spring means toward the orifice.

4. The fluid diaphragm modulator of claim 3 wherein said flat spring includes an outer ring portion and a central lid portion aligned with said first orifice means, and a plurality of equicircumferentially spaced arms connected between said ring portion and said lid portion, said arms permitting linear flatwise movement of said lid portion.

5. The fluid diaphragm modulator of claim 1, wherein said chambers are formed in stacked relation with a common wall between said coupling chambers, said first orifice being formed in said common wall, and said second orifice being formed in a wall of said second coupling chamber opposite said common wall.

6. The fluid diaphragm modulator of claim 1, wherein chamber means includes a plurality parallel spaced planar walls defining said chambers with a common wall between said coupling chambers, said first orifice means being formed by an offset nozzle in said common wall projecting into said first coupling chamber toward said diaphragm, and said second orifice means being formed by a similar offset nozzle in the wall of said second coupling chamber opposite said common wall.

7. The fluid diaphragm modulator of claim 6 wherein chambers are circular and said diaphragm wall means includes a flat disc flexible diaphragm clamped about the periphery within said chamber means to said chamber walls, said diaphragm wall means includes a flat spring means clamped at the periphery in overlying engagement with said diaphragm, said spring means having a central flat lid portion secured to an outer ring portion by a plurality of spaced arms, said arms extending radially and circumferentially of the lid and permitting linear flatwise movement of said lid portion.

8. The fluid diaphragm modulator of claim 7 wherein said arms include four circumferentially spaced arms, each of said arms being essentially L-shaped with one end secured to the lid portion and the opposite end secured to the ring portion.

Claims

1. A fluid diaphragm modulator comprising a chamber means including a diaphragm wall means common to a first coupling chamber and a signal chamber, an input signal means connected to said signal chamber for selectively positioning said diaphragm wall means, a first orifice means in said coupling chamber in aligned opposed relation to said diaphragm wall means, a second orifice means mounted in spaced aligned relation to said first orifice means outwardly of said coupling chamber, said first orifice means being larger than said second orifice means and being closely spaced whereby a stream emitted from said second orifice means and passing freely through said first orifice means aspirates fluid, a second coupling chamber means enclosing the space between said first and second orifice means, a pressurized fluid supply means connected to said second orifice means and a fluid reference means connected to said first coupling chamber whereby a continuous stream is established through said orifice means with said diaphragm spaced from said first orifice means, and a load means connected to said second coupling chamber for providing in response to said input signal an output signal at said second coupling chamber varying from an aspirating condition to said supply means pressure in accordance with the position of said diaphragm wall relative to said first orifice means.