Controller With Adjustable Proportionality Range
Abstract
A controller with adjustable proportionality range wherein a ring is acted upon by a pressure differential in measuring unit formed as, for example, pairs of bellows or the like. The measuring units have axes of effectiveness which are perpendicular to each other. The ring cooperates as a baffle ring with a pivotable nozzle. The measuring units are articulated in diametrical opposition to the ring with the axes of effectiveness of one of the measuring units extending radially and the axis of effectiveness of the other measuring unit extending tangentially of the ring or in parallel to the tangential direction. The present invention relates to a controller and, more particularly, to a controller with an adjustable proportionality range wherein a ring is acted upon by pressure differences in measuring units formed as, for example, pairs of bellows or the like, having axes of effectiveness which are perpendicular to each other, with the ring cooperating as a baffle ring with a pivotable nozzle. Controllers of the aforementioned type have been proposed in, for example, German Pat. No. 1,126,657 wherein the measuring units are arranged as bellows within a baffle ring in a cross shape so that the two ends of the bellows are respectively attached to an inner circumference and a cube-shaped central member. A disadvantage of this proposed construction is that a deflection due to the exposing of one of the pair of bellows to a pressure, does not leave the other pair of bellows unaffected, because the bellows pairs are coupled with each other due to their mounting to the ring. Since the ring is merely held by the four bellows at their respectively outer ends, even a static pressure exposure of the ring by the bellows may deform the ring. In German Offenlegungsschrift No. 1,523,489, it has been proposed to replace the baffle ring by a circular segment. However, a disadvantage of this proposed construction is that displacements caused by one pair of bellows exposed to a pressure exert, through the circular segment, a torque on the other pairs of bellows producing error sources in the overall comparator system. The object of the present invention is to provide a control device or controller wherein different control variables do not influence one another and wherein the ring of the controller is prevented from being deformed by exposure to static pressures. In accordance with the advantageous features of the present invention, the measuring units are articulated to the ring in diametrical opposition with an effective axis of one measuring unit extending radially and an effective axis of the other measuring unit extending tangentially or in parallel to a tangential direction. Because the measuring units of the present invention are articulated to the ring in diametrical opposition and the effective axis of one of the measuring units extends radially; whereas the effective axis of the other measuring unit extends tangentially or in parallel to the tangential direction, displacements of the measuring units evoked by pressure differential are decoupled from each other. Consequently, there is no disturbance of the control properties by a transmission of a movement of a pressure-exposed measuring unit to a measuring unit which is not exposed to pressure. Moreover, a deformation of the baffle ring due to static pressures is avoided since the measuring units do not rest on the baffle ring, but merely transmit the displacements corresponding to the pressure differences. Another advantage of the present invention is that the points of connection or application of the measuring units are in diametrical opposition so that the effective axis of the measuring units intersect one another at the point of connection or application. Because of this, one measuring unit will act in a tangential direction or in a direction parallel to the tangential direction. The unit which acts on the ring in the radial direction effects a parallel displacement of the ring along the effective direction; whereas, the measuring unit acting in the tangential direction effects a pivoting of the ring about the point of application of the measuring unit acting in the radial direction. By a superposition of these two direction components, the baffle ring may be shifted with respect to the nozzle into any desired direction within the desired range with a nozzle pivot arm cooperating with the baffle ring over a possible angular range of 360.degree.. Of course, the movement executed in the effective axes may also be the resultant of several measuring units coupled with each other by way of a lever. Therefore the controller system of the present invention exhibits symmetry to a straight connecting line of points of articulation. Advantageously, the measuring units are pairs of bellows, with the points of application or connection of the respective pairs of bellows at the circumference of the ring being constructed as ball bearings. The ball bearings are seated, without clearance, in bores in a region of the circumference of the baffle ring. Therefore an almost frictionless transmission of the displacements to the ring is ensured. The ring may be turned without friction about the point of application of the bellows pairs acting in the radial direction after being exposed to a pressure by the pair of bellows acting in the tangential direction. Thus, the displacements corresponding to the pressure differences may be transmitted without losses to the baffle ring, attaining a very exact control. An advantageous arrangement of the pairs of bellows is to arrange the bellows in a plane below the baffle ring so that one pair of bellows lies within a circumferential radius of the baffle ring in a direction in parallel to the tangent and the other pair of bellows lies in the radial direction. Additionally one bellows of the bellows pair acting in the radial direction is located within the circumferential radius of the baffle ring and the other bellows lies outside the circumferential radius of the baffle ring. Thus, a compact construction is achieved which does not require any special transmitting means for the displacements of the bellows to the baffle ring such as, for example, a lever or spring connection. Because the bellows are arranged so that it is easy to mount vertically extending pins to central sections of the pairs of bellows, which connect the pairs of bellows to the baffle rings through the ball bearings. Advantageously, a spring mounting may be provided for the transmission pin at the pair of bellows which has an effective axis oriented tangentially or in parallel to the tangential direction. Advantageously, the spring mounting may take the form of a leaf spring which includes two nestled, U-shaped leaf spring brackets jointed together at their ends, with the mounting for the transmission pin attached to the outer bracket and with the inner bracket connected by suitable fasteners such as, for example, screws or the like to a central section of the pair of bellows. Because of this leaf spring, the displacement of the pair of bellows which takes place in the tangential direction is transmitted directly to the baffle ring, without frictional losses. Whereas, if a pressure is exerted on the pair of bellows acting in the radial direction, the upper bracket of the leaf spring, wherein rests the transmission pin in the ball bearing of the baffle ring, will be spread apart with respect to the inner bracket. The inner bracket is fixedly joined to the pair of bellows acting in the tangential direction so that a parallel displacement of the ring in the radial direction is possible without impairing or deflecting the effective axis of the bellows measuring unit acting in the tangential direction. It is also advantageous to arrange one or both pairs of bellows in a plane beneath the baffle ring outside of a circumference of the baffle ring and to transmit the movements of the pairs of bellows caused by exposure to pressure to the baffle ring by means of suitable elements such as, for example, leaf springs or lever arms. Preferably, this arrangement may be chosen if no special requirements must be met with regard to the spatial dimensions of the controller and, for example, if the control is to be executed by the cooperation of two nozzles with the baffle ring. Because there are no bellows mounted in a plane beneath the ring within the circumference there is sufficient space for arranging a collecting nozzle or the like. As with the construction described hereinabove, the lever arms or the leaf springs necessary for transmitting the displacement to the baffle ring may be connected through ball bearings with the baffle ring so that an exact mode of operation of the controller is not impaired. In order to obtain a compact controller arrangement, the nozzle is pivotably mounted to a nozzle stem so that an orifice of the nozzle points in a radial direction to the inner circumference of the baffle ring. Thus, regulation takes place over a distance between the inner circumference of the baffle ring and the orifice of the nozzle so that a height of the controller may be relatively low, and the bellows may be arranged in a plane within a circumference lying beneath the baffle ring. It is also possible in accordance with the present invention to provide for different arrangements to obtain the necessary cooperation between the nozzle and the baffle ring. For example, a control may be effected by an edge regulation by providing the nozzle swivel arm in a plane above the baffle ring and by mounting the nozzle to an underside of the swivel arm in a vertical direction above an inner edge of the baffle ring. This is accomplished so that an orifice of the nozzle points toward an upper inner edge of the baffle ring. With such an arrangement, a movement of the pairs of bellows then displaces the baffle ring beneath the nozzle orifice with respect to the latter so that the air pressure in the orifice of the nozzle varies in dependence upon a movement of the baffle ring. It is also possible in accordance with the present invention to fashion the baffle ring as a flat member and to mount a jet nozzle above a top inner edge of the baffle ring. It is also possible to mount a receiving nozzle or collecting hole below the bottom inner edge of the baffle ring by a bifurcate nozzle swivel arm, with an air stream flowing in a vertical direction from the jet nozzle to the receiving nozzle. Thus, the aforementioned baffle ring is movable between the orifice of the jet nozzle in a horizontal direction to vary the flow cross sections thereof. This arrangement offers the advantages of recovering a high percentage of the air stream which can thus be returned to the control circuit. Consequently, it is not necessary for the pressure supply source to make large amounts of compressed air available. A further advantage of constructing the baffle ring of a flat shape is that if vibrations occur, the baffle ring cannot knock against the jet nozzle. Thus, it is possible to provide for a shock proof regulation in an extremely simple manner. It is also possible in accordance with the present invention, to hold or mount two jet nozzles by a bifurcate nozzle swivel arm above a top inner edge of the baffle ring, as well as below a bottom inner edge of the baffle ring. With such an arrangement, the air flows from below as well as from above onto the inner edge of the baffle ring. Also, the pressure differential or differences which occur based upon the position of the baffle ring between the two nozzles results in a signal pressure which may then be utilized for control purposes. In order to affix the nozzle swivel arm in a predetermined position with respect to the baffle ring and to ensure a constant adjustment of the nozzle during an operation of the controller, in accordance with further advantageous features of the present invention, the nozzle swivel arm is held or mounted at the nozzle stem by a threaded connection. Accordingly, it is an object of the present invention to provide a controller which avoids, by simple means, shortcomings and disadvantages encountered in the prior art. A further object of the present invention is to provide a controller with an adjustable proportionality range which is simple in construction and, therefore, relatively inexpensive to manufacture. A still further object of the present invention is to provide a controller which functions reliably under all operating conditions. A further object of the present invention is to provide a controller wherein different control variables do not influence one another. A still further object of the present invention is to provide a controller having a plurality of measuring units with the actions of the respective measuring units not affecting the remaining measuring units. Yet another object of the present invention is to provide a controller which minimizes, if not avoids the generation of potential error sources.
Metadata
Assignee
- Eckardt AG
Inventor
- Horst Bader
Application Information
Classifications
Patent Drawings (2 sheets)
Description
Claims
Patent Citations (4)
| Patent | Date | Inventor | Cited By |
|---|---|---|---|
| US2585347 | 1952-02-01 | Robins | |
| US2661754 | 1953-12-01 | Donaldson, Jr. | |
| US3090395 | 1963-05-01 | Weiss et al. | |
| US3448753 | 1969-06-01 | Marucci et al. |