US2633385A - Jet pipe assembly - Google Patents

Description

March 3l, 1.953 H. ZIEBoLz 2,633,385

JET PIPE ASSEMBLY Filed Deo. 22, 1949 2 SHEETS-SHEET l i JNVENTOR. /3 I le March 3l, 1953 Filed Dec. 22, 1949 2 SHEETS-SHEET 2 45.94 lo .50 i L4] 49 I i te* 45) l g 36 afs ,0 I Q75 l /28 @l 4 C) Q 5/ M L t /ee E fl l Z 46 Patented Mar. 31, 1953 JET PIPE ASSEMBLY Herbert Ziebolz, Chicago, Ill., assignor to Askania Regulator Company, Chicago, Ill., a corporation of Illinois Application December 22, 1949, Serial No. 134,483 6 Claims. (Cl. 299-73) This invention relates to relay controllers of the jet pipe type, comprising a nozzle from which a continuous stream of fluid is delivered under substantial pres-sure, and which is pivoted at a point spaced axially of the nozzle to the rear of its di-scharge end, to be swung by a mechanical signal for varying its degree of registration with a receiver port to proportion the pressure generated within the receiver port to the magnitude of the applied mechanical signal.

Such devices present many advantages, such as high sensitivity to weak signals and great power amplification, extremev simplicity and ruggedness, and low cost operation. The present invention constitutes a marked improvement in 'jet pipe assemblies, principally by reason of the elimination of certain characteristics of prior types that have required them to be of certain practical minimum size. The arrangement comprising the present invention -permits jet pipe assemblies to be made much smaller and compact than has heretofore been possible, without sacrificing any of their well known advantageous characteristics.

A serious problem of jet pipe arrangement heretofore has been presented by the conilicting requirements of high sensitivity to weak signals, calling for the pivot mounting on which the jet nozzle swings to present lowest possible frictional resistance, of necessary accuracy of relation of the swing path of the discharge end of the nozzle relative to the receiver port or ports, and of providing for supply of fluid under pressure to the interior of the nozzle for discharge toward the receiver. While many proposals have been made of various fluid connections arranged to supply uid to the nozzle, and to not interfere with sensitivity or accuracy, the most practical solution has been to mount the nozzle in radial ldisposition on a tubular spindle, onev end of which .is mounted in a rotary bearing that permits the .spindle to swing about its own axis, while the yopposite end is supported in a hollow bearing providing communication between a fluid supply and the interior of the spindle. In order to minimize frictional resistance to rotative movement of the spindle as the nozzle is swung, the hollow bearing has been arranged to supply a floating action -between the stationary structure and the spindle, a small clearance being provided between the relatively movable parts, and a thin iilm of the operating fluid escaping through such clearance and tending to minimize lateral displacement between the spindle and the stationary bearing structure. A slight play, however, must exist in the heating bearing structure,- ZI'he @Heet or this play has been minimized to an entirely satisfactory and wholly lpractical degree by spacing the nozzle a substantial distance from the iioating, fluid-conducting bearing, and by applying the signal to the nozzle at a point substantially spaced from the axis of the spindle. While these expedients have resulted in highly satisfactory operation, as fully evidenced .by the l-ong and successful use of jet pipe controls, they have imposed certain minimum length limits for spindle and nozzles, and consequently jet pipe assemblies heretofore have been characterized by certain minimum sizes and' Weights that have excluded them from certain fields of application.

One object of the present invention is to provide a jet pipe controller assembly arrangement that eliminates the necessity for a floating bearing to conduct pressure uid to the internal bore of the swinging discharge nozzle.

Another object is the novel arrangement of a jet pipe spindle providing for conduction of operating luid by a substantially friction-free coupling.

Still another object is the provision of a novel jet pipe assembly arrangement that permits accurate and secure fixing of the spindle axis, to provide high accuracy of the discharge nozzle swing path, without impairment of sensitivity by resistance to rotative movement of the spindle.

Another object is the provision of a novel jet pipe assembly that may be made very small and compact without impairment of accuracy and sensitivity characteristics.

In the accompanying drawings:

Fig. 1 is a median longitudinal section of a jet pipe assembly constructed in accordance with a preferred form of the invention.

Fig. 2 is a plan of such an assembly. Fig. 3- is a transverse section on line 3 3 of Fig. 1. Y

Fig. 4 is a transverse section on line 4-4 of Fig. 1. v

Fig. 5 is an enlarged detail sectional view show'- ing a spindle bearing assembly at one end of the assembly.

Fig. 6 is a longitudinal median section of a jet pipe assembly arranged according to a modied form of the invention.

Fig. 7 is a plan of the assembly `of Fig. 6.

Fig. 8 is a section on line 8-'8 of Fig. 6.

Fig. 9 is a longitudinal median section of a jet pipe assembly arranged in 'accordance with another modification of the invention.

Describing the drawings in detail, and iirst referring to the form of invention disclosed by Figs.

1 to 5, the assembly comprises a main body port I that conveniently may be in the form illustrated, of a solid block. machined to provide the various bores, ports, chambers, etc., to be described. The jet pipe unit proper comprises a spindle II that carries adjacent but spaced from one of its end-s the nozzle pipe I2, the latter proj ecting radially from the spindle through an opening I3 in the side of the bodyL The discharge bore I of the nozzle is in open communication with an interior passage I5 of the spindle. As shown, the nozzle may be mounted on the spindle by a block I6 located in a recess il of the body,- and having right angularly relatedbores I8, I9 in which the spindle and nozzle end respectively are engaged, as shown in Fig. d. To one side of the nozzle I2 a cylindrical part of the spindle II and its internal passage I5 extend into a cylindrical bore 2U in the body I0, with which bore the spindle is preferably coaxial. The bore 2!) is sufficiently larger than the spindle to provide a small annular clearance between the spindle and bore wall surfaces, such clearance being shown greatly exaggerated and designated 2i. The clearance is sufficiently large to avoid surface to surface contact throughout the entire opposed surface areas of the bore wall and spindle, thereby permitting escape of fluid to recess I3 but is sufficiently small and of sufcient length relative to its width to provide substantial rcsistance to such flow of the particular fluid used in the assembly at the pres-sure under which fluid is supplied, thereby limiting the now rate of fluid so escaping. As an example, in a system in which oil of a type commonly employed with such devices is used at a pressure or the order of one hundred pounds per square inch, a clearance of the order of three one-thousandths of an inch will avoid frictional contact between the spindle and body, but in a quite short reach will provide suflicient resistance to oil flow to prevent either substantial volume ilow oi cil or .pressure drop.

The ends of the spindle II are closed, as by plugs 22, which provide mountings for' antifriction bearing assemblies 23 that rotatably mount the spindle and accurately nx its axis relative to the body I0 and bore 20. In the drawings the bearing assemblies 23 comprise ball bearings, the inner races of which cooperate with mounting studs 25 that are iixed relative to the body and its bore 20, and with respect to which the spindle is nxed in coaxial but rotatable relation. In all positions of the spindle as it is swung with the nozzle, the clearance 20 is maintained by the bearing assemblies at the opposite ends of the spindle. Conveniently, the studs are formed as projections of mounting elements 25 that are axially adjustable in the main structure. The elements 26 include cylindrical parts 2l, such part of one element acting as a plug for the end of the bore 20, as shown in Fig. 5, while at the opposite end of the spindle the mounting element 26 is supported by an end structure 28 that is secured to the body I Il by screws 29. The mounting elements 26 have screw threaded portions 30 that engage in threaded bores of split clamping portions 3| of the body Ill and end structure 28. Screws 32 provide for clamping of the split p0rtions 0n the thread parts of the mounting elements to nx the axial positioning of the spindle Il, and consequently of the plane in which the axis' of the nozzle I2 swings, so that the swing path of the nozzle may be correctly located and xed relative to a receiver, suchas is shown at 33 in Fig. 2. The use of anti-friction bearings to 4 mount the spindle permits rigid location of its axis beside providing practically friction-free swinging whereby the angular position of the nozzle, and consequently its registration with the receiver ports may be accurately controlled by a very weak signal force applied to the nozzle.

Fluid under pressureis introduced to the internal passage I5 of the spindle for discharge through the nozzle by the following arrangement. A fluid port 34 enters the body I0 in angular relation to the bore 20 and at a point intermediate the ends of such bore and spaced from the recess Il. A chamber 35, that communicates with port 34, surrounds' the spindle at a location between, and spaced from each end of bore 20, spacing of such chamber from recess Il being sunicient that the uid escape path from the chamber to the recess II, provided by the clear-ance 2i) is long enough to afford substantial resistance to now of iiuid. Within the chamber 35 the spindle is provided with entrance ports 36- providing for entrance of uuid to the spindle passage l5 regardn less of the angular position of the spindle.

The arrangement described above provides the accurate and rigid positioning of the path of the nozzle end relative to a receiver, desirable for accuracy of translation of a mechanical signal applied to the nozzle into magnitude of fluid pressure in the receiver port, provides for supply of fluid to the nozzle Without resort to exible or fluid tight, high friction connections and provides the substantial freedom from frictional resistance necessary for sensitivity to weak signals.

The arrangement also permits considerable flexibility of direction from which a signal force is applied, and of the location of the part of the jet pipe unit to which such signal force is applied. In Figs. 1A, 2 and 4, a pad 31 is secured to the nozzle pipe I2 at a suitable location, spaced axially of the nozzle from the spindle. In the prior practice, briefly described above, it has vbeen usual to position a nozzleesupportd signal receiving' pad. such as 31, at a location relative to the spindle axis, and to the previously used floating bearing, chosen to afford optimum response of the nozzle end to the signal and minimum lateral motion eect on the floating bearing end of the spindle. In the present arrangement,A since the axis of the spindle is rigidly xed against lateral deflection under a signal force, regardless of the point of application of such force, a signal-applying arrangement inay be designed purely in accordance with characteristics of the signal and type of response of the nozzle tiet is'required. Thus in Fig. l, the pad 31 may be located at any point along' the lever arm structure provided by the nozzle pipe I2, and a location suitable to produce a given angular 'movement of the nozzle per unit of signal variation may be selected without any limitation or allowance for deflection of the spindle axis. Similarly, a signal may be applied from directions other than perpendicular to the axis of the nozzle when in its neutral position. In Figs. 6 and '7, a side arm 38 secured to the nozzle mountingblock 39, and extends radially of the spindle,V at right angles to the axis of the nozzle, through an extension 40 of the blockreceiving recess di of the assembly. Ey employment of this expedient a signal may be applied from directions other than at right angles to the nozzle axis when the nozzle is in its neutral position, without resort to a device for converting the direction of signal application to the hitherto normal one of such right angular relation.

Various arrangements may be resorted to in and the body I0.

the details for controlling flow and exertion of pressure upon the spindle, as permitted by the clearance necessary to free operation. Referring to Figs. 1 and 6, it will be seen that the clearance between spindle I I and the bore 2l) extends beyond the fluid chamber 34 to the adjacent end of the body I0, as it must to avoid contact between the entire relatively movable surfaces of the spindle Additionally, the arrangement of stud 25 and the spindle-carried bearing assembly 23 provides a space 42 between the spindle end and the adjacent end of the bore-plugging part 2'I of the element 26. Evidently fluid will be present in the extended clearance and in the space 42, and under the supply pressure such uid will tend to force the spindle axially toward the other bearing assembly. In Fig. 1, the force thus exerted axially on the spindle is reduced by providing a relief port 43 to the space 42. By means of an adjustable valve assembly 44 the flow of fluid from the space 42 may be regulated to minimize pressure within the space while preventing too great a loss of fluid.

Fig. 9 discloses an arrangement for balancing out the effect of pressure within the end space 42. In this arrangement the second plug and bearing assembly, designated 45, and the end portion of the spindle I I are enclosed by a bore 46 in the end structure 28, the arrangement of the bearing being such as to provide an enclosed space 4'! at the end of the spindle. The bore 46 is sufficiently large to provide at 48 a clearance space between the bore wall and spindle surface, similar to the clearance 2| previously described, and similarly preventing frictional contact of the spindle with stationary structure. A passage 49 provides communication between the space 4'I and the iiuid supply line, being shown as entering the supply port 34 within the body I il. By this arrangement, pressure is developed in space 46 to oppose pressure exerted axially upon the spindle by fluid present in the space 42. Pressures in the two spaces 42, 41 may be equalized by adjustment of the valve assembly 44 that controls area of relief port 43 to space 42, thereby permitting compensation for different lengths of uid escape paths at the two ends of the spindle.

Escape cf pressure fluid from the supply chamber 35 to the nozzle block recess, I'I of Fig. 1 or 4| of Fig 6, may be reduced if necessary or desirable by means designed to increase the length of the escape path. One form of such means, disclosed by Figs. 6 and 8 comprises one or more cylindrical flanges 49 projecting from the surface of the nozzle mounting block 39, each such flange extending into a matching annular recess 50 in the body I0. Each such recess has a configuration to provide narrow clearance at 5I between opposite cylindrical surfaces of the flange and recess wall.

From the foregoing it will be evident that the mounting of the jet pipe spindle between two anti-friction bearings that rigidly x the axis of the spindle, provides great accuracy of location of the plane in which the nozzle axis swings and prevents deflection of the nozzle axis from such plane by signal forces or by extraneous forces such as shock or vibration. It alsov is evident that this arrangement permits application of the signal force at any location, selected solely with regard to the signal characteristics and without necessity of considering whether signal application at a particular location would have a disturbing effect on the accuracy of the system. The mounting of the spindle between -rigid positioning bearings is permitted by the introduction of operating fluid to the interior of the spindle at a point between the bearings, and such introduction is in turn made practical by the friction free character of the seal provided by narrow clearance between the spindle surface and surrounding bore Wall in the region of such introduction. Consequently the assembly arrangement herein disclosed solves the problem of providing a jet pipe control in extremely compact form, without impairment of the extremely useful characteristics of such devices that hitherto have been practical only in much larger assemblies.

I claim:

1. A jet pipe assembly comprising body structure providing an enclosed chamber, an elongate cylindrical bore intercepted between its ends by said chamber, a fluid supply port communicating with said chamber, and a laterally open recess spaced axially of said bore from said chamber and into which said bore opens, a spindle having a cylindrical part arranged within said bore in concentric relation thereto and of sufficiently less diameter to provide between their opposite surfaces an annular clearance space of suflicient width to prevent their contact and of suicient narrowness to'oifer material resistance to fluid flow, said spindle part extending past said chamber and into said recess, a nozzle supported at one end within the recess by the spindle and projecting in angular relation to said spindle, said spindle having an internal passage for supply of uid to said nozzle opening into said chamber, and bearing means arranged at opposite ends of said spindle arranged to maintain its axis in a fixed position relative to said body structure and for permitting said nozzle and spindle to swing about said axis.

2. A jet pipe assembly comprising body structure providing an enclosed chamber, a uid supply port communicating with said chamber, a laterally open recess spaced from said chamber, and a cylindrical bore opening at its opposite ends respectively into said recess and through a surface of the body structure, said bore being intercepted between its ends by said chamber, a spindle having a cylindrical part arranged within said bore in concentric relation thereto and of a diameter suiiiciently smaller than that of the bore to provide between their opposite surfaces an annular clearance space of suiiicient width to preclude contact of said surfaces and sufficiently narrow to offer material resistance to fluid flow therethrough, said spindle portion extending past said chamber and having an internal passage opening into the latter, said spindle and passage projecting into said recess, a nozzle supported at one end within the recess by the spindle, projecting angularly therefrom and having a discharge bore communicating with said internal passage, an assembly arranged within the bore beyond the end of the spindle including bearing means and means closing said bore and bearing means, second bearing means arranged to the opposite side of the nozzle and recess. said bearing means supporting said spindle between them and being arranged to maintain its axis in a fixed position relative to said body structure and to permit the spindle and nozzle toswing about said axis.

3. A jet pipe assembly according to claim 2, wherein the spindle extends across said recess beyond said nozzle, and wherein said second bearing means is supported by the body structure 7 opposite the opening ofsaidbore into said recess.

42. A jet pipe assembly according to claim 2, wherein said bore-closing means encloses a space between itself and the spindle end, and including means providing a relief passage from such space.

5. A jet pipe assembly according to claim 2, wherein said body structure isprovided on the side of the lrecess opposite said bore with a second bore axially aligned with said first bore, the spindle extends across said recess beyond the nozzle and into such second bore, spaces are enclosed beyond the respective ends of the spindle, and said body structure is provided with a passageway connecting the space beyond the rst end of the spindle and the enclosed space beyond said second end of the spindle.

6. In a jet pipe assembly that includes a discharge nozzle and a spindle supporting said nozzle in angularly projecting relation to its axis, said spindle having an internal passage for supplying fluid to the nozzle; a body member having an internal bore, an opening through a side of the body and into which said bore opens, an internal chamber spaced from said opening and into which said bore opens and a fluid supply passage leading into said chamber from an externa-l supply opening in said body member, said spindle having a portion position in said bore and extending between said supply chamber and opening and having a cross section sufciently smaller than the cross section of said bore to provide throughout the entire extent of opposition of bore and lateral spindle surfaces and continuous between said chamber and opening clearance space of sulcient Width to prevent their contact and of sufficient narrowness to oier material resistance to fluid flow, and bearing means respectively disposed to opposite sides of said opening and chamber and supporting said spindle for rotation about a xed axis.

HERBERT ZIEBOLZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 350,569 Strobel Oct. 12, 1886 422,017 Harris Feb, 25, 1890 1,165,705 Perkins Dec. 28, 1915 1,310,733 Bore July 22, 1919 2,107,971 Wunsch Feb. 8, 1938 2,507,668 Hamilton May 16, 1950

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