US3313313A

US3313313A - Fluid pressure reference

Info

Publication number: US3313313A
Application number: US358964A
Authority: US
Inventors: Katz Silas
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-04-10
Filing date: 1964-04-10
Publication date: 1967-04-11
Anticipated expiration: 1984-04-11

Description

Filed April 10, 1964 I REFERENCE? FIG? INPUT PRESSURE ATTORNEY United States

Patent Ofilice

3,3 l3,3 l3 Patented Apr. 11, 1967 3,313,313 FLUID PRESSURE REFERENCE Silas Katz, Silver Spring, Md, assignor to the United States of America as represented by the Secretary of the Army Filed Apr. 10, 1964, Ser. No. 358,964 6 Claims. (Cl. 137-815) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to me of any royalty thereon.

The present invention relates to fluid devices having no moving mechanical parts, and more particularly to purely fluid devices which utilize the Coanda or fluid latch effect to direct the flow of a jet.

The problems of reliability and durability of control and processing system components under conditions of environmental extremes have led to the development of a class of devices known as pure fluid elements. These devices are basically a plurality of ducts and channels which carry fluid. A typical device is constructed by cutting, forming or etching the channels in a block of solid material and covering the channels with a coverplate, thereby closing them in on all sides The function performed by a typical device would be determined by the way in which flow is directed through the various channels. ince there are no moving parts through which the fluid must move, problems such as extreme wear, lubrication, fatigue failure, and corrosion are substantially or completely eliminated.

The prior art has conceived some elaborate combinations to perform one or another of the functions performed by the present invention such as sensing ressure and flow levels, producing discrete outputs at predetermined reference levels of pressure and flow, relieving overpressures and regulating pressure levels. The present invention satisfies the need to perform these functions in one very simple and compact component with not. a single moving part.

Therefore, an object of the present invention is to provide a purely fluid means of sensing a pressure and fiow level in a fluid system.

Another object of the present invention is to provide a simple device which gives discrete output pressures and flows when the input pressure and flow reach a predetermined reference level.

A further object of the present invention is to provide a simple and reliable purely fluid relief valve.

Still another object of the present invention is to provide a nomoving-part pressure regulator.

In accordance with one aspect of the present invention these and other objects are accomplished by use of a device which comprises an orifice nozzle which produces a jet flow into a chamber at one end of such chamber with outlet channels located at the opposite end of the chamber. A wall located at the nozzle exit and olfset from the nozzle centerline causes the jet to attach to the wall and flow out the channel on the wall side. As supply pressure behind the nozzle is increased, the jet stream spreads and successively passes out the remaining outlet channels. Varying the level of pressure acting on the nozzle above a reference level produces a discrete signal unaffected by downstream loading of the device. In other words the device responds to precisely the same predetermined input regardless of what sort of load is attached to its output.

The foregoing and other objects of the present invention will be more fully apparent from the consideration of the following description and drawings in which:

FIG. 1 is a sectional plan view of a device constructed in accordance with the present invention showing a flow condition which is produced by a pressure below the desired reference level;

FIG. 2 is a sectional view of the device of FIG. 1 in which the inlet pressure, and correspondingly flow, have increased above the reference level;

FIG. 3 shows a graph of output pressure versus input pressure; and

FIG. 4 is a sectional plan view of a device constructed in accordance with the present invention having many outlet channels.

The fluid device of FIGS. 1 and 2 comprises .a source of varying pressure 1, a nozzle 2 connected by a pipe 3 to the source of pressure which serves to deliver flow in a coherent jet stream 4 to an interaction chamber 5, a near wall 6 located near the nozzle outlet and offset from it with which the jet issuing from the nozzle 2 interacts, and a near wall outlet receiver channel 7 which receives the flow of the jet stream 4 on the near wall side of the chamber 5. A far channel 8 and a far wall 9 are located opposite the near wall 6 and the near receiver channel 7.

In the condition shown in FIG. 1 there is no flow out the far receiver channel 8 because the far wall 9 is offset a greater distance from the inlet nozzle 2 than is the near wall 6 and the flow tends, therefore, to attach to the nearer wall. A flow indicator vane 10, or other flow indicator, is located in the far outlet channel 8, and indicates a zero flow condition. Absence of flow out the far receiver channel indicates that the desired reference level has not been reached at the source 1.

In the condition shown in FIG. 2 the source pressure has been increased so that the stream 4 now spreads and leaves the device through both near outlet receiver 7 and far outlet receiver 8. The far offset wall 9 serves to guide the flow out the far receiver channel 8. The fluid latch produced at the far wall 9 is weak compared with the latch at the near wall 5 so that, as the source ressure is decreased below the reference level, the jet stream 4 will always detach from the far wall 9 and return to the near wall 6 so that all the flow will go out the near receiver channel 7. The flow indicator 10 shows that a signal is being produced in the far outlet channel 8.

Placement of the far wall 9 will have an effect on the performance of the device but as long as it is offset farther from the nozzle 2 than the near wall 6 is offset, the device is operable. An oifset ratio of 3 to 1 would insure dependable operation The location of the outlet receivers may be shifted about the nozzle centerline as a means of tuning the output in relation to the input signal; however, a satisfactory configuration is produced with the receivers arrayed symmetrically about the nozzle centerline.

No external control signals are necessary to actuate the device. The physical characteristics of the power source create a phenomenon when interacting with the geometry of the device that produces the desired functions without the need for controls of any sort.

FIG. 3 shows graphically the abrupt increase in pressure at the far output receiver 8 when the input pressure of source 1 rises above a critical reference level.

FIG. 4 is another embodiment of the present invention comprising an inlet nozzle 11 communicating with chamber 12 which has a restricting wall 13 forming one side. A first outlet channel 14 a second outlet channel 15 and a third outlet channel 16 each receive flow signals at discrete predetermined levels of flow through nozzle 11 as such flow is successively raised to these levels. Flow through nozzle 11 is related to pressure level at source 17 in a known relationship which can be regulated by choice of nozzle size.

It can be seen from the foregoing that the present invention provides a simple and dependable means of sensing, indicating and regulating pressure and flow.

O Other configurations can be imagined by a person skilled in the art without the necessity of further invention. For example, the far wall could be removed entirely. In addition, in the embodiment having two outlet channels with careful design the stream could always be directed out one side or the other but not from both sides simultaneously.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

I claim as my invention:

1. Apparatus responsive to increase of fluid input pressure above a predetermined level, comprising:

(a) a source of varying fluid pressure,

(b) nozzle means connected to said source for producing at the output of said nozzle means a fluid jet the amplitude of which increases with increase in the pressure of said source,

(c) a chamber connected to the output of said nozzle means for receiving said fluid jet,

(d) first and second output channels leading from the end of said chamber remote from said nozzle means,

(e) the axis of said first and second output channels and of said input nozzle lying substantially in a first plane,

(f) said chamber having a first sidewall that is substantially continuous with one wall of said first output channel and having a second sidewall that is substantially continuous with one wall of said second output channel,

(g) said second sidewall being offset from the axis of said nozzle, the distance from said second sidewall to the axis of said nozzle being greater than the distance from said first sidewall to the axis of said nozzle, (h) whereby (1) fluid entering said chamber from said input nozzle attaches itself more readily to said first sidewall than to said second sidewall,

(2) substantially all fluid entering said chamber from said input nozzle leaves through said first output channel when the pressure of said fluid input is less than a certain fixed critical value,

(3) a portion of the fluid entering said chamber from said input nozzle leaves through said second output channel only when the pressure of said fluid input is at least equal to said critical value.

2. Apparatus in accordance with claim 1, wherein the sidewalls of said chamber are offset from said input nozzle, the offset of said sidewall on the side of said second output channel being greater than the offset on the side of said first output channel, so that the fluid jet from said nozzle tends to attach to the sidewall on the side corresponding to said first output channel in preference to the sidewall corresponding to said second output channel.

3. Apparatus in accordance with claim 2, wherein the outer portions of the inner walls of said first and second output channels are substantially straight continuations of the corresponding sidewalls of said chamber.

4. Apparatus in accordance with claim 2, there being additionally provided at least a third output channel, said third output channel being positioned between said first and second output channels and having its axis substantially in said first plane.

5. Apparatus in accordance with claim 3, there being additionally provided means responsive to the presence of flow from said second output channel.

6. Apparatus in accordance with claim 4, there being additionally provided first means responsive to the presence of flow from said third output channel and sec ond means responsive to the presence of flow from said second output channel.

Reierences Cited by the Examiner UNITED STATES PATENTS 3,001,539 9/1961 Hurvitz 137--81 3,159,168 12/1964 Reader 13781 3,168,897 2/1965 Adams et al 13781 3,182,674 5/1965 Horton l37-81 3,194,253 7/1965 Havee 13781 3,204,652 9/1965 Bauer 137-81 3,217,727 11/1965 Spyropoulos 13781 3,219,048 11/1965 Palrnisano 137-81 FOREIGN PATENTS 1,136,518 9/1962 Germany.

M. CARY NELSON, Primary Examiner.

S. SCOTT, Assistant Examiner.

Claims

1. APPARATUS RESPONSIVE TO INCREASE OF FLUID INPUT PRESSURE ABOVE A PREDETERMINED LEVEL, COMPRISING: (A) A SOURCE OF VARYING FLUID PRESSURE, (B) NOZZLE MEANS CONNECTED TO SAID SOURCE FOR PRODUCING AT THE OUTPUT OF SAID NOZZLE MEANS A FLUID JET THE AMPLITUDE OF WHICH INCREASES WITH INCREASE IN THE PRESSURE OF SAID SOURCE, (C) A CHAMBER CONNECTED TO THE OUTPUT OF SAID NOZZLE MEANS FOR RECEIVING SAID FLUID JET, (D) FIRST AND SECOND OUTPUT CHANNELS LEADING FROM THE END OF SAID CHAMBER REMOTE FROM SAID NOZZLE MEANS, (E) THE AXIS OF SAID FIRST AND SECOND OUTPUT CHANNELS, AND OF SAID INPUT NOZZLE LYING SUBSTANTIALLY IN A FIRST PLANE, (F) SAID CHAMBER HAVING A FIRST SIDEWALL THAT IS SUBSTANTIALLY CONTINUOUS WITH ONE WALL OF SAID FIRST OUTPUT CHANNEL AND HAVING A SECOND SIDEWALL THAT IS SUBSTANTIALLY CONTINUOUS WITH ONE WALL OF SAID SECOND OUTPUT CHANNEL, (G) SAID SECOND SIDEWALL BEING OFFSET FROM THE AXIS OF SAID NOZZLE, THE DISTANCE FROM SAID SECOND SIDEWALL TO THE AXIS OF SAID NOZZLE BEING GREATER THAN THE DISTANCE FROM SAID FIRST SIDEWALL TO THE AXIS OF SAID NOZZLE, (H) WHEREBY (1) FLUID ENTERING SAID CHAMBER FROM SAID INPUT NOZZLE ATTACHES ITSELF MORE READILY TO SAID FIRST SIDEWALL THAN TO SAID SECOND SIDEWALL, (2) SUBSTANTIALLY ALL FLUID ENTERING SAID CHAMBER FROM SAID INPUT NOZZLE LEAVES THROUGH SAID FIRST OUTPUT CHANNEL WHEN THE PRESSURE OF SAID FLUID INPUT IS LESS THAN A CERTAIN FIXED CRITICAL VALUE, (3) A PORTION OF THE FLUID ENTERING SAID CHAMBER FROM SAID INPUT NOZZLE LEAVES THROUGH SAID SECOND OUTPUT CHANNEL ONLY WHEN THE PRESSURE OF SAID FLUID INPUT IS AT LEAST EQUAL TO SAID CRITICAL VALUE.