US3174498A

US3174498A - Pneumatic control device

Info

Publication number: US3174498A
Application number: US150437A
Authority: US
Inventors: Frederick D Joesting
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1961-11-06
Filing date: 1961-11-06
Publication date: 1965-03-23
Anticipated expiration: 1982-03-23

Description

March 23, 1965 F. D. JOESTING 3,174,498

PNEUMATIC CONTROL name Filed NOV. 6. 1961 I NVENTOR.

FREDERICK 0. JOE .ST7N6 ATTORNEY United States Patent "ice 3,174,498 PNEUMATIC CONTROL DEVICE Frederick D. Joesting, Park Ridge, Ill., assignor to Honeywell Inc., a corporation of Delaware Filed Nov. 6, 1961, Ser. No. 150,437 Claims. (Cl. 137-82) My invention relates to a pneumatic control device and more particularly to an improved pneumatic control device of the bleed type. This invention is directed specifically to an improved control valving in a pneumatic control device and specifically to an improved nozzle flapper or closure member arrangement. It is therefore the principal object of this development to provide in a pneumatic control device of the bleed type simplicity in design of a valving in the form of a lapped flapper nozzle arrangement which provides reduced frictional force and positive closure to give accuracy in operation and economy in maintenance and cost. This improved pneumatic control valve or valving is shown herein in connection with a one pipe or bleed type pneumatic thermostat or pneumatic control device which is included in the drawings of which:

FIGURES 1 and 2 are side elevation and plan views in section of the improved pneumatic nozzle fiappers or closure member arrangement,

FIGURE 3 is a sectional view of the thermostat of FIGURE 4, and

FIGURE 4 is a plan view of a thermostat using the improved nozzle flapper embodiment.

The improved nozzle or disc and nozzle assembly shown in FIGURES l and 2 provides an improved valving or control for a pneumatic control device. As will be seen in FIGURES 1 and 2, the nozzle assembly is basical- 1y square in cross-section at its exposed extremity or through its main body such as is indicated at with a reduced circular section 11 at one extremity for mounting purposes, a passage 12 through the body 10 which terminates in a nozzle 13 at the opposite extremity of the body. Main passage 12 connects with nozzle 13 through a passage 14 having the same diametrical dimension as the nozzle. The body 10 has an annular ridge section 15 near the outer periphery of the same which is the same height as the nozzle 13. It will be understood that passage 12 is connected to a supply conduit 16 having a restriction 17 therein, and having a branch outlet conduit 18 connected between the restriction and the nozzle. The nozzle has internal dimensions relative to the restric tion sizing or dimensions to give a ratio of diameters of approximately 3 to 1 and up to a ratio of 5 or 6 to 1. Thus the area ratios would be up to approximately 35 to 1. These nozzle and ridge sections are lapped or ground to an accurate dimension and cooperate with a flat disclike member or flapper 29 which also has its undersurface ground and mated with the exposed surface of the nozzle and the ridge section 15 on the body. The flat disc is very light in weight and is designed to be moved relative to the nozzle 13 through a very small application of force or through positioning movements requiring light forces. The disc 20 is held on the end of the nozzle or positioned thereon by means of retaining member 22 which is annular in form. The retainingmember 22 may be pressed down over the edges or corners of the body 10 of the nozzle assembly or otherwise suitably secured thereto. This permits a simplified three piece assembly which contains all of the critical parts of the valve and permits the other portions of the associated apparatus to be less critical and expensive.

This nozzle assembly permits a limited passage of air from the nozzle through the retaining member to the open extremity thereof in addition to the normal bleed along the nozzle. The retaining member 22 has a shoulder 3,174,498 Patented Mar. 23, 1965 portion 23 which acts to retain the disc or flapper 20 and the interior dimensions of member 22 are slightly larger than the diametrical dimensions of the disc 20 so as to permit tilting of the disc as it moves away from the nozzle and limited floating of the same within the retaining member. Frictional forces are substantially reduced since the disc and retaining member are circular in form and of different diameters and can come in contact at only one point. The limited flow around the disc also acts to reduce these frictional forces. The shoulder portion 23 of the retaining member provides an opening indicated at 24 adjacent the nozzle exposing the disc 20 such that an external positioning movement or force may be applied to the disc 20 from a thrust member of a condition sensor or other control. This application of force is not re quiried to be accurately centered and the contact may take place anywhere near the center and still provide accurate seating of the disc on the nozzle or positioning of the disc relative to the nozzle in the case of a modulating type of valve. Thus, in FIGURE 1, a thrust member or positioning member engaging the disc 20 is indicated generally at 25 which is not required to be accurately located. While I have shown the nozzle as basically square in cross-section except for the reduced mounting portion 11, it will be understood that this portion of the nozzle assembly may be cylindrical, or if desired, any of many forms, with the simple provision for spacing and connection between the retaining member 22 and the nozzle element 10 to permit air flow therebetween. Thus, the nozzle element will be exhausted to atmosphere through a one pipe pneumatic control or bleed type pneumatic control arrangement.

The actual leakage between the disc or closure member 20 and the retainer member 22 through the exposed aperture 24 of the retainer is relatively insignificant and such flow reduces frictional forces and facilitates opening of the valve. Slight cocking of the disc member 20 relative to the nozzle does not appreciably affect the pressure established in the passage 12 or the control passage for the nozzle. Branch line pressure or pressure in the pipe to the nozzle is controlled by the position of the flapper relative to the nozzle extremity.

The improved flapper nozzle or closure member and nozzle construction in FIGURES 1 and 2 is shown applied to a thermostat design in FIGURES 3 and 4 which show a plan and an elevation view in section of a typical device. While the particular valving is shown in connection with a thermostat, it will be understood that the improved pneumatic control device can be operated by any type of condition sensor.

Thermostat 30 shown generally in FIGURES 3 and 4, includes a metallic base member 31 fitted into a plastic base member 32, the metallic base member being provided for engaging the wall and connecting to the metal tubing or control lines indicated at 35 supplying a source of fluid pressure to the one pipe control device and having a restriction therein and an outlet conduit connected thereto in which the control pressure is to be established through operation of the condition sensor. The thermostat 38 is shown in position on an object such as a wall 38 with the pipe or tubing 35 extending through an opening 41 therein. The tubing is secured to the metallic backing plate 31 by means of a threaded flange 42 which abuts on the undersurface of the metal backing plate 31 and clamps to the tubing through a pressure fit. The flange 42 is secured to the plate by means of a nut 43 positioned over the threaded portion of the backing plate 42. Thus the tubing or an extension of the same is secured to and projected beyond the wall 38. The nonmetallic or plastic base or support 32 is recessed to house the metal backing plate 31 on its back surface and is recessed on its front surface to mount the valve and sensor parts of the thermostat and provide a mounting for a cover to be later defined. Positioned on the front surface of the base 32 and over the nut 43 or the extension of the tube 35 is a nozzle supporting section 45 which is generally rectangular in configuration and is supported on a base and connected to the metal plate 31 by means of screws such as indicated at 48. The nozzle supporting section includes a cylindrical recess 46 communicating with the tube 35 in which the nozzle is mounted as will 'be later defined. The nozzle assembly such as is indicated in FIGURES 1 and 2 is suitably mounted in the recess 46' by press fitting or other means and suitably secured thereto. Thus, as in FIGURES 1 and 2, section 11 fits into the recess 46 providing an exposed body upon which the retainer 22 is mounted to house the floating disc '20 and permit the entrance of a thrust member which is curing of the nozzle supporting section as well as the frame assembly on the base parts 32 and 31.

The adjusting frame section 50 basically includes a pair of arms "53, 54 which extend from the flanges or which carry the flanges 51, 52. These arms 53, 54 are connected by a cross member or connecting member 55, the purposes of which will be later noted. As indicated in FIGURE 4,

this connecting section 55 has a knife edge groove therein at 58 which extends across the member 55 and accommodates a knife edge type plate 60 which carries a spring adjusting arm 61 for the thermostat. The spring adjusting arm 61 has an aperture therein through which is positioned a pin 63 mounting a spring 64 and an adjusting nut 65, thespring being positioned over the arm 61 and the pin 63 being attached to the cross arm section 55 through suitable means not shown. The free end of the arm 61 carries an adjustable cam follower 68 which cooperates with an annular cam 76, the purpose of which is to adjust the position of ti e arm 61 and hence the bias on the plate 60 carrying the bimetal 72 as will be later noted. Cam 7 0 is mounted on the nozzle supporting section 45 being suitably attached thereto through screw means 73 which journal the cam thereon permitting rotation of the same. Attached to the cam is an adjusting arm 75 which extends along the base of the thermostat intermediate the arms 53, 54 ofthe adjusting frame section 59 and under the connecting section 55 thereof to be exposed at the base of the thermostat as indicated in FIGURE 3. This arm overlies and is adapted to be positioned relative to an indicia 76 positioned on the base parts 33 and suitably secured thereto by means not shown. The knife edge pivoting plate 60 which rides in the groove 58 of section 55 also carries the bimetal 72 which is suitably secured thereto through securing means such as rivets or screws 7 The bimetal extends at an angle such that the free extremity thereof will be positioned over the nozzle flapper arrangement and such that the thrust pin 25 which is suitably secured thereto will contact the floating disc 28 to adjust the valving of the control device and establish a branch'linepressure in the tubing or conduit 35 connected thereto. Thus, as is conventional in thermostats, the bimetal is mounted with a bias applied to the same through the plate 60, the bias being adjusted by means of the cam and arm '70, 61 as controlled by the position of the lever 75 Positioned over the thermostat is a cover assembly indicated generally at which includes a thermostat element indicated generally at 86 in the cover surface thereof. 7 The cover member is regular in form and fits the rectangular shape of the base member 32 being secured thereto but accessible for removal through suitable means not shown.

While the improved nozzle flapper or disc assembly has been shown herein in conection with a thermostat, it will be understood that any other type of pneumatic condition control device may be utilized or the assembly may be incorporated therein. This improved nozzle flapper arrangement permits a simplicity of parts while providing for minimum friction and accuracy in control response. The disc 20 positioned by the retaining member 22 on the body 10 of the assembly has suflicient clearance from the retaining member so that it will freely float with a minimum of contact with'its retainer and be positioned relative to the orifice extremitylZ and the ridges 15 to establish a branch line pressure in accordance with the relative position of these parts. Relatively small forces are required to position the disc or flapper 20 to produce the control pressure in proportion thereto.

In considering this invention it should be remembered that the present disclosure is intended to be illustrative oniy, and the scope of the invention'is to be determined only by the appended claims.

I claim as my invention:

1. In a pneumatic bleed type control device, nozzle means, conduit means connected to said nozzle means and adapted to be connected to a source of fluid pressure, a restriction positioned in said source and an outlet passage means being connected to said conduit means between said restriction and said nozzle means, a disc type closure member positioned on said nozzle means and adapted to cooperate therewith to establish a variable control pressure in said conduit means, retaining means mounted on said nozzle means and enclosing said disc closure member and having an opening therein,the ratio of the dimension of said disc closure member and said retaining means providing clearance for limited contact between said member and said means, and limited flow around said disc closure means to float the same within said retaining means, and means projecting through said opening in said retaining means and contacting said disc closure means to position the same in accordance with a condition to establish said control pressure in said outlet passage means in proportion to said condition.

2. In a pneumatic bleed type control device, nozzle means, conduit means connected to said nozzle means and adapted to be connected to a source of fluid'pressure, a restriction positioned in said source and an outlet passage means being connected to said conduit means between said restriction and said nozzle means, the ratio of the diameters of said nozzle means to said restriction being in the range of three to one, a disc type closure member positioned on said nozzle means and adapted to cooperate therewith to establish a variable control pressure in said conduit means, retaining means mounted on said nozzle means and enclosing said disc closure member and having an opening therein, the ratio of the dimension of said disc closure member and said retaining means providing clearance for limited flow around said disc closure means to float the same within said retaining means, and means projecting through said opening in said retaining means and contacting said disc closure means to position the same in accordance with a condition to establish said control pressurein said outlet passage means in'proportion to said condition.

3. In a pneumatic bleed'type control device, nozzle means, conduit means connected to said nozzle means and adapted to be connected to a source of fluid pressure, a restriction positioned in said source and an outlet passage means being connected to said conduit means between said restriction and said nozzle means, said restriction and said nozzle means having internal dimensions which have an area ratio approximately one to thirty, a disc type closure member positioned on said nozzle means and adapted to cooperate therewith to establish a variable control pressure in said conduit means,

said closure member in said nozzle means having lapped cooperating surfaces, retaining means mounted on said nozzle means and enclosing said disc closure member and having an opening therein, said disc closure member being freely movable within said retaining means, and means projecting through the opening in said retaining means and contacting said disc closure member to posi tion the same in accordance with a condition to establish said control pressure in said outlet passage means in proportion to said condition.

4. In a pneumatic bleed type control device, nozzle means, conduit means connected to said nozzle means and adapted to be connected to a source of fluid pressure, a restriction positioned in said source and an outlet passage means being connected to said conduit means between said restriction and said nozzle means, the ratio of the diameters of said nozzle means to said restriction being less than ten to one, a disc type closure member positioned on said nozzle means and adapted to cooperate therewith to establish a variable control pressure in said conduit means, retaining means mounted on said nozzle means and enclosing said disc closure member and having an opening therein, the ratio of the dimension of said disc closure member and said retaining means providing clearance for limited flow around said disc closure means to float the same within said retaining means, passage means between said nozzle means and said retaining means to bleed fluid from said nozzle means, and means projecting through said opening in said retaining means and contacting said disc closure means to position the 0 same in accordance with a condition to establish said control pressure in said outlet passage means in proportion to said condition.

5. In a pneumatic bleed type control device, nozzle means, conduit means connected to said nozzle means and adapted to be connected to a source of fluid pressure, a restriction positioned in said source and an outlet passage means being connected to said conduit means between said restriction and said nozzle means, the ratio of the diameters of said nozzle means to said restriction being approximately three to one, a fiat closure member positioned on said nozzle means and adapted to cooperate therewith to establish a variable control pressure in said conduit means, retaining means connected to said nozzle means and positioning said closure member thereon, said retaining means having at least an opening therein exposing said closure means, and means projecting through said opening in said retaining means and contacting said closure member to position the same relative to said nozzle means in accordance with a condition to establish said control pressure in said outlet passage means.

References Cited by the Examiner UNITED STATES PATENTS 2,408,685 10/46 Rosenberger.

2,898,048 8/59 Stucka 23687 2,914,076 11/59 Zimmerli 137-85 XR 2,915,078 12/59 Ochs 137-82 XR 3,055,384 9/62 Puster 13785 ISADQR WEIL, Primary Examiner.

WILLIAM F. ODEA, Examiner.

Claims

1. IN A PNEUMATIC BLEED TYPE CONTROL DEVICE, NOZZLE MEANS, CONDUIT MEANS CONNECTED TO SAID NOZZLE MEANS AND ADAPTED TO BE CONNECTED TO A SOURCE OF FLUID PRESSURE, A RESTRICTION POSITIONED IN SAID SOURCE AND AN OUTLET PASSAGE MEANS BEING CONNECTED TO SAID CONDUIT MEANS BETWEEN SAID RESTRICTION AND SAID NOZZLE MEANS, A DISC TYPE CLOSURE MEMBER POSITIONED ON SAID NOZZLE MEANS AND ADAPTED TO COOPEATE THEREWITH TO ESTABLISH A VARIABLE CONTROL PRESSURE IN SAID CONDUIT MEANS, RETAINING MEANS MOUNTED ON SAID NOZZLE MEANS AND ENCLOSING SAID DISC CLOSURE MEMBER AND HAVING AN OPENING THEREIN, THE RATIO OF THE DIMENSION OF SAID DISC CLOSURE MEMBER AND SAID RETAINING MEANS PROVIDING CLEARANCE FOR LIMITED CONTACT BETWEEN SAID MEMBER AND SAID MEANS, AND LIMITED FLOW AROUND SAID DISC CLOSURE MEANS TO FLOAT THE SAME WITHIN SAID RETAINIG MEANS, AND MEANS PROJECTING THROUGH SAID OPENING IN SAID RETAINING MEANS AND CONTACTING SAID DISC CLOSURE MEANS TO POSITION THE SAME IN ACCORDANCE WITH A CONDITION TO ESTABLISH SAID CONTROL PRESSURE IN SAID OUTLET PASSAGE MEANS IN PROPORTION TO SAID CONDITION.