SELF-ADJUSTING JET BREAKER FOR IMPACT SPRINKLERS

Abstract: A self-adjusting jet breaker (200) for impact sprinklers, including a spout (T) connected to a pressurized water supply line (L) by means of a rotary coupling (R); the spout is provided with a terminal nozzle (U) for generating a jet (G) and with an oscillating arm (B) which is provided with a baffle (D); the device is arranged on the oscillating arm and includes an active surface adapted to interact with the jet between two successive oscillations of the arm. The active surface of the device has an angle of inclination tau with respect to the longitudinal axis of the arm such as to be substantially tangent to the jet when downward transit through the jet from above begins and such as to be inclined during the entire downward transit and vice versa, so as to always receive an upward thrust (F). The device optimally distributes and breaks up the jet, and increases the beat frequency in an automatic manner, i.e. adapting to both high and low jet supply pressures.

Description: SELF-ADJUSTING JET BREAKER FOR IMPACT SPRINKLERS The present invention relates to a self-adjusting jet breake device, particularly for impact sprinklers. The breaker device according to the invention can be mounte on impact sprinklers of the type described, for example, i the Italian patent application No. 85608 A/90 in the name o this same Applicant. Such sprinklers generally comprise spout which is connected to a supply line by means of braked rotary coupling, with a terminal nozzle for generatin a jet and an oscillating arm provided with a baffle whic periodically interferes with the jet. In said sprinklers, the baffle, during its interference wit the jet, captures part of the kinetic energy of said jet imparting to the arm an instantaneous rotary torque whic tends to cause both the oscillation of the arm and th rotation of the spout in steps of preset breadth. The baffl furthermore has the function of periodically breaking th fluid column so as to distribute the water proximate to th sprinkler as well. However, when the pressure of the jet is low, its breakup i limited due to the slow rate at which said jet interacts wit the baffle. If one wishes to increase the oscillatio frequency of the arm even with low jet supply pressures, thi cannot be achieved by means of conventional fixed-geometr baffles but by modifying, within certain limits, the balanc of the arm or possibly the rigidity of resilient members. The aim of the present invention is to provide a jet break device which allows to significantly increase the be frequency for an equal jet pressure. An object of the present invention is to provide a sel adjusting jet breaker device which is able to improve t breakup of the jet especially at low pressures, leaving i maximum range substantially unchanged. Another object of the present invention is to provide a je breaker device which can interact with the jet.in one or bot of the rotation directions of the sprinkler. Not least object of the present invention is to provide a je breaker device which has an extremely simple and economica structure. This aim, these objects and others which will become apparen hereinafter are achieved by a jet breaker device of the abov described type, having the characteristics of the independen claim 1. A jet breaker device of this type can be applied to existin impact sprinklers so as to significantly increase the bea frequency and intensify the breakup of the jet in one or bot of the directions in which the sprinkler rotates about it own vertical axis. Further characteristics and advantages will become apparen from the detailed description of some preferred but no exclusive embodiments of the self-adjusting jet breake device according to the invention, illustrated only by way o non-limitative example in the accompanying drawings, wherein Figure 1 is a general perspective view of a jet breake device according to the invention, installed on a per s known impact sprinkler; Figure 2 is a top view of the arrangement of Figure 1; Figure 3 is an enlarged perspective view of the jet breake device of Figures 1 and 2; Figure 4 is a diagram of the operation of the device o Figure 3; Figure 5 is a perspective view of a second embodiment of th device according to the invention; Figure 6 is a view of the device of Figure 5 in a differen operating condition; Figures 7 and 8 are schematic views of the operation of th device shown in Figures 5 and 6. A jet breaker device according to the invention, generall designated by the reference numeral 200, is mounted on a impact sprinkler designated by the letter I. The sprinkle comprises a spout T which has a braked coupling R at one end Coupling 12 can rotate about a vertical axis, and is adapte to connect the spout to a pressurized water supply line Coupling R is also rigidly associated with a frame, which i not shown in the drawings. A nozzle U for generating a jet G is arranged at the free en of the spout T, while an oscillating arm B is pivote proximate to its central portion. A baffle D is arranged a the outer end of the arm and is used to periodically an impulsively capture part of the energy of the jet in order t make the arm oscillate about its fulcrum and thereby rotat the spout about its own vertical axis. It is evident that th device according to the invention can be equally installed o sprinklers of a different type, provided that they have th same general characteristics. The jet breaker device 200 comprises one or more activ surfaces which can be anchored to the arm B, for example, i an intermediate position between its oscillation axis and th baffle, so as to interact at least once with the jet betwee two successive oscillations of the arm. Alternatively, th device 200 might also be mounted at a greater distance fro the baffle, achieving the same final result. In the first embodiment, shown in detail in Figure 3, th device 200 comprises a pedestal 201 which is anchored to th arm B, by means of a fixing plate 202, on one side wit respect to its centerline M. A bracket support 203 is fixe at the top of the pedestal 201 and is provided with a groove guide 204. Guide 204 slidingly accommodates a blade 20 provided with a sharp edge 207 and with an elongated fixin hole 208. The active surface of the device, which is intende to interfere with the jet, is constituted by the lower fac of the blade 206. Blade 206 is fixed in position along th guide 204 of the support 203 by means of a bolt 209 whic passes through the elongated hole 208. It is thus possible t arrange the device 200 on one side or on both sides wit respect to the longitudinal axis of the arm B, so that the blade interferes with the jet during the rotation of the sprinkler in one direction or in both directions. As can be seen in Figure 4, the bracket support 204 is inclined with respect to the axis of the pedestal 201, so that the blade 206 forms an angle τ with the longitudinal axis M of the arm B. The height of the pedestal 201 and the shape of the bracket support 204 are also such that the blade is at a minimum distance H from the longitudinal axis of the arm. Thus, after the arm has started its downward oscillation starting from its upper stroke limit, the jet G initially interacts with the baffle D, causing the arm B to rotate downward without encountering the jet breaker device. At a certain point, the blade 206 of the jet breaker 200 will begin to skim the jet G, being approximately parallel to the axis thereof, as indicated by the position 206' shown in broken lines in Figure 4. In this position, a substantially nil perpendicular force acts on the blade, while the positive sharpening angle of the leading edge of the blade facilitates its penetration in the jet. As the arm moves downward, the negative incidence of t blade 206 with respect to the jet gradually increases. Thu in this step part of the jet is progressively deflecte downward, giving said jet a peculiar fan shape. The reacti F which acts at right angles and upward on the blade als increases correspondingly, generating a braking torque on th arm, i.e. a torque which tends to dampen the downwar oscillation and to cause the early reversal of the directio of rotation of the arm, which coincides with its lower strok limit. The braking torque will be maximum in the lowe position, designated by 206" in Figure 4, which coincide with the position in which the blade enters the jet durin the upward movement of the arm. Thus, in its upward movement the blade 206 interacts with the jet G, exerting a accelerating torque on the arm, i.e. a torque which tends t facilitate its upward movement. This acceleration in ascent combined with braking during descent, determines an overal increase in the beat frequency of the arm, and thus in th rotation rate of the sprinkler. Naturally, once the jet ha abandoned the region of interference with the breaker an with the baffle, it can resume its shape, achieving it maximum range. At high pressure, the blade transit speed i such as to cause a sudden and effective breakup of the je both during its downward movement and during its upwar movement. Experimental tests have shown that blade inclination angles comprised between 15° and 30°, and preferably equal t approximately 25°, give the best results in varying th frequency and breakup of the jet. The distance H can var according to the size of the baffle D and according to th distance from the arm oscillation axis. The second embodiment of the jet breaker, shown in Figures and 6, wherein the corresponding elements have bee designated by the same reference numerals, differs from th first one in that it has a pair of active surfaces havin different inclinations, instead of a single surface. I particular, the active surfaces are constituted by the lowe faces of two deflector wings 210, 211 which extend radiall and on opposite sides of a ratchet 212. Ratchet 212 i mounted on the adjustable-length pedestal 201 so as to b able to rotate vertically. The wings 210 and 211 have convex shape, similar to a wing contour, with a median axi which forms respective angles Φ-^ and Φ 2 with respect to th longitudinal axis of the arm. By means of a snap-locking device, the ratchet 212 can b rotated manually and retained in two diametrically opposit fixed positions, so as to expose only one of the wings 21 and 211 to the jet, as clearly shown in Figures 5 and 6. Figures 7 and 8 schematically illustrate the fact tha operatively the angle Φ j is such that the median axis of th wing 210 is approximately parallel to the direction of th jet during transit through said jet. Therefore, the wing 21 is used mainly to break up the jet without transmittin appreciable forces to the arm during its oscillation. On th contrary, the angle Φ of the wing 211 is such that the je is always inclined with respect to the wing 211 during it interference. This will cause, on the lower surface of th wing 211, a thrust with a perpendicular component F directe upward, which applies a clockwise torque to the arm, with a effect similar to the one described for the model of Figur 3. The above description and experimental tests show that th jet breaker device according to the invention achieves th intended aim and objects and in particular it is noted tha it produces an optimum distribution and breakup of th jet together with an increase in the beat frequency in a automatic manner, i.e. adapting to both high and low je supply pressures. The device according to the invention i also simple and economical to manufacture and easy t install on existing sprinklers with no modification of thei structure. The device thus conceived is susceptible to numerou modifications and variations, all of which are within th scope of the inventive concept. expressed in the accompanyin claims. All the details may furthermore be replaced with technically equivalent elements. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: CLAIMS 1. Self-adjusting jet breaker device (200) for impac sprinklers, comprising a water spout T with a nozzle U fo generating a jet G and an oscillating arm B provided with baffle D, characterized in that it is arranged on said arm a a selected distance from the oscillation axis of said arm and in that it comprises at least one first active surfac (206, 210, 211) said surface being adapted to interact wit said jet between two successive oscillations of said arm. 2. Device according to claim 1, characterized in that sai active surface has such an angle (τ) of inclination wit respect to the longitudinal axis M of said arm B that it i substantially tangent to the jet at the beginning of it downward transit through said jet from above. 3. Device according to claim 2, characterized in that sai active surface is progressively inclined with respect to th axis of the jet during transit through said jet, so as t receive an upward thrust. 4. Device according to claim 1, characterized in that sai active surface is constituted by the lower face of substantially planar blade (206) which is fixed to the top of a pedestal (201) which can be anchored to said arm by means of a fixing plate. 5. Device according to claim 1, characterized in that th average inclination angle (τ) of said blade with respect t the longitudinal axis of said arm is comprised between 15 and 30' 6. Device according to claim 5, characterized in that sai blade (206) can move along a guiding groove (204) defined i a bracket support (203) , said blade having an elongate central hole (208) for anchoring in said guide of sai bracket support in lateral terminal positions. 7. Device according to claim 5, characterized in that it ha a second active surface (211) mounted at the top of sai support in a position which is diametrically opposite an with a different inclination angle Φ 2 with respect to th first active surface (210) . 8. Device according to claim 8, characterized in that sai first active surface (210) and said second active surfac (211) extend radially from a ratchet (212) which is mounte so as to be able to rotate at the top of said pedestal an can be arranged in two diametrically opposite fixed angula positions. 9. Device, according to claim 5, charaterized in that sai angle (τ) is approximately 25°.

Inventors: DRECHSEL ARNO, DRECHSEL, ARNO
Applicants: DRECHSEL ARNO, DRECHSEL, ARNO
Application year: 1992
Main classification: B05B3
IPC codes: B05B3