Sprinkler head

Abstract: A sprinkler head of the invention comprises a body (I) having a water discharge port (3) formed at the center thereof, a valve (10) for opening and closing the water discharge port (3) of the body (1), a receiver seat (7) provided in a position opposing the valve (10), a heat sensitive member (15) disposed between the valve (10) and the receiver seat (7) for supporting the valve (10), the heat sensitive member (15) being disintegrable when heated, causing the valve (10) to move away from the water discharge port (3) of the body (1), and a frame for supporting the receiver seat (7) with respect to the body (1). To reduce directional dependency of exposure of a hot air stream to the heat sensitive member for an improvement in sensitivity of the heat sensitive member, the frame includes a plurality of arms (6a,6b) each having at least one draft hole (9a-9d) formed therein, or a plurality of arms provided in inclined relation with respect to the heat sensitive member, or at least three arms.

Description: The present invention relates to a sprinkler head which is automatically opened by heat in the event of the occurrence of fire for sprinkling water. The above-mentioned type of sprinkler head is always supplied at its water discharge port with pressurized water, and the water discharge port is closed by a valve. To provide a sufficient sealing ability in such an arrangement, a gap between the valve and the water discharge port is sealed by a copper packing. The valve is supported along with a heat sensitive member such as a low melting-point alloy or a glass bulb by a frame comprising a horseshoe-shaped arm, so that a large load is applied to ensure the sealing ability of the valve. Fig. 7 shows a frame type sprinkler head described in Japanese Utility Model Publication No. 5-24348. This sprinkler head comprises a screw portion 22 screwed into a pipe (not shown), a pair of horseshoe-shaped frame yokes 23a, 23b having a boss 24 in opposite relation to the screw portion 22, the screw portion and the frame yokes being formed in an integral structure, and a disassemble portion 26, serving as a heat sensitive member, disposed between the boss 24 and a valve 25 closing a water discharge port. Incidentally, 27 denotes a deflector. In the frame type sprinkler head mentioned above, if a fire occurs and a hot air stream comes into contact with the disassemble portion 26 to heat it, the disassemble portion 26 is disassembled and falls down together with the valve 25. The water discharge port is thereby opened, allowing the water in the pipe to be discharged and sprinkled to surroundings by the deflector 27. Fig. 14 shows another frame type sprinkler head described in Japanese Utility Model Publication No. 57-3331. This sprinkler head is constituted such that a flange 32 is formed at an outer peripheral edge of a water introduction port 31 having a threaded outer peripheral surface, a valve 33 sealing the water introduction port 31 through a copper packing 34 is supported by a glass bulb 35, and arms 37a, 37b of a support 36 are inserted through the flange 32 and then fixed by nuts. Denoted by 38 is an adjustment screw provided at a lower central portion of the support 36 for not only supporting the glass bulb 35 between itself and the valve 33, but also adjusting the load imposed on the valve 33 to a predetermined value. In the frame type sprinkler head mentioned above, if a fire occurs and a hot air stream comes into contact with the glass bulb 35, a thermally expanding agent, such as alcohol, in the glass bulb 35 is expanded and pressurized to blow up the glass bulb. The valve 33 thus falls down to open the water introduction port 31 for sprinkling water. However, any of the foregoing conventional frame type sprinkler heads has a very low sensitivity to a hot air stream coming in directions of the frame arms. This is because a cross-sectional area of the arm must be set so large for bearing the great load imposed on the valve that a hot air stream coming in a direction of the arm 37a toward the glass bulb 35, for example, passes by to the opposite side without directly contacting the glass bulb 35, as shown in Fig. 9. On the other hand, since a hot air stream coming in directions perpendicular to the arms 37a, 37b directly strikes against the glass bulb 35, the glass bulb 35 operates with a normal sensitivity and blows up. Such a tendency is equally applied to the sprinkler head shown in Fig. 7. It has thus been deemed that the frame type sprinkler head inevitably has directionality in sensitivity of its heat sensitive member. To solve the above-mentioned problem in the sprinkler head using the glass bulb 35, it is conceivable to increase a diameter of the glass bulb 35 so that a hot air stream in the arm direction may easily contact the glass bulb 35. However, this would raise the problem of increasing a wall thickness of the glass bulb 35 and hence reducing its sensitivity. Furthermore, the heat sensitive member such as a low melting-point alloy or a glass bulb is a very important part and, if a shock is applied from the outside, the heat sensitive member would be broken, causing an unexpected accident such as a leakage of water. Because the heat sensitive member is protected by only two arms, there has been a problem that the heat sensitive member is apt to easily break upon application of external forces. A further sprinkler head is disclosed in GB 2 188 841. In view of solving the problems as set forth above, an object of the present invention is to provide a sprinkler head which has no directionality in sensitivity of a heat sensitive member for an improvement in the sensitivity thereof, and which can increase a function of protecting the heat sensitive member. Accordingly a sprinkler head according to the present invention comprises the features of Claim 1. Preferred features of the invention are set out in Claims 2 to 9. Figs. 1 to 3 are a plan view, a front view and a vertical sectional view showing a sprinkler head according to Embodiment 1 of the present invention, respectively, Figs. 4 and 5 are a front view and a perspective view showing a further sprinkler head, Fig. 6 is a sectional view taken along line A-A in Fig. 4, Fig. 7 is a front view showing a conventional sprinkler head, Fig. 8 is a front view showing another conventional sprinkler head, and Fig. 9 is a diagram for explaining operation of the sprinkler head of Fig. 14. Preferred embodiments of the invention will now be described, by way of example. Embodiment 1: Referring to Figs. 1 to 3, a sprinkler head body 1 comprises a screw portion 2 having a water discharge port 3 axially formed therein and male threads formed on its outer periphery, a hexagonal flange 5 formed at a lower end of the screw portion 2 in an integral structure therewith, and a pair of arms 6a and 6b extending downwardly from a lower surface of the flange 5 in opposite relation to each other. As shown in Fig. 3, the body 1 has a recess 4 formed along an inner peripheral wall defining a lower end of the water discharge port 3. The arms 6a and 6b are provided in positions opposed to each other with draft holes 9a to 9f penetrating the arms toward a central axis of the body 1, and have respective lower ends coupled together on the central axis of the body 1 to form a receiver seat 7. Note that the flange 5 is not necessarily limited in its shape to a hexagon, but it may be formed into a disk-like shape, for example, with engagement portions provided on an outer periphery thereof which is to be engaged with an attaching/detaching tool. A valve 10 is configured such that a disk-like flange is radially extended from a lower end of a column. A recess 11 is formed on a lower surface of the flange, and a bottom-equipped guide hole 12 opening to the recess 11 is formed to extend along a central axis of the valve. The flange of the valve 10 has a diameter slightly larger than that of the water discharge port 3 of the body 1, and is held in abutment against the recess 4 of the body 1 with the intervention of a packing 13 made of elastic materials therebetween. A threaded hole 8 is formed in the receiver seat 7 of the body 1 to extend in the axial direction of the body 1, and a setting screw 14 is screwed into the threaded hole 8. Between the valve 10 and the setting screw 14, there is held a glass bulb 15 which is filled with a thermally expanding agent, such as alcohol. A deflector 16 is attached to a lower end of the receiver seat 7. A sprinkler head comprising the above-mentioned components such as the body 1, the valve 10, the setting screw 14 and the glass bulb 15 is assembled by first inserting the column portion of the valve 10 into the water discharge port 3 of the body 1 through an open space between the arms 6a and 6b with the intervention of a packing 13 therebetween. Then, the setting screw 14 is loosened and a distal end portion of the glass bulb 15 is inserted into the guide hole 12 of the valve 10, while the glass bulb 15 is held at an opposite end by the setting screw 14. By screwing the setting screw 14 into the threaded hole 8, the glass bulb 15 is fixedly supported between the valve 10 and the setting screw 14. In this connection, the load imposed on the glass bulb 15 is adjusted by changing the amount through which the setting screw 14 is screwed into the threaded hole 8. The sprinkler head thus assembled is attached to a ceiling surface by screwing the screw portion 2 into a water supply pipe provided in the ceiling. At this time, a great load is imposed on the valve 10 by pressurized water introduced through the water supply pipe, but there is no fear of leakage of the pressurized water because the valve 10 is held in place by the glass bulb 15 interposed between itself and the setting screw 14 and the gap between the body 1 and the valve 10 is sealed by the packing 13 made of elastic materials. If a fire occurs and a hot air stream is produced, the hot air stream moves upwardly, passes through the open space between the arms 6a and 6b, and then contacts the glass bulb 15 to heat it. When the hot air stream comes closer while flowing in the direction of the arm 6a (or 6b) toward the glass bulb 15, it passes through the draft holes 9a, 9c, 9e (or 9b, 9d, 9f) provided in the arms 6a (or 6b), and then contacts the glass bulb 15. Therefore, the presence of the arms 6a, 6b gives rise to no appreciable undesired effect. If the glass bulb 15 is heated by the hot air stream, the thermally expanding agent filled therein is expanded and pressurized to blow up the glass bulb 15 supporting the valve 10. The valve 10 falls down through the space between the arms 6a and 6b to open the water discharge port 3 so that the pressurized water is discharged and sprinkled through the deflector 16. Generally, the hot air stream in the vicinity of the ceiling flows along the ceiling, and the hot air stream in lower part flows toward the ceiling. Therefore, the hot air stream can more smoothly pass through the draft holes by forming them such that the draft holes 9a, 9b provided in upper portions of the arms 6a, 6b are substantially parallel to the ceiling surface, whereas the draft holes 9c, 9d, 9e, 9f provided in middle and lower portions of the arms 6a, 6b are inclined downwardly. Thus, with this embodiment, since the plurality of draft holes 9a to 9f allowing the hot air stream to pass therethrough are provided in the arms 6a, 6b, a heat sensitive member, i.e., the glass bulb 15, has no appreciable directionality in sensitivity and hence has an improved sensitivity. As a modification, the arms 6a, 6b may have a ladder-like shape by forming the arms 6a, 6b in a wider width and increasing the size of the draft holes 9a to 9f so as to cover the glass bulb 15 by the arms in a larger circumferential range. This makes it possible to increase a function of protecting the glass bulb 15. Further, the draft holes 9a to 9f may be joined to each other into the slit form for each arm. Figs. 4 to 6 show a further sprinkler head. Note that the same parts as those in Embodiment 1 are denoted by the same reference numerals and will not be described here. In this sprinkler head, a pair of opposing arms 18a, 18b are formed in a substantially Y- or V-shape, the arms having upper ends joined together to the screw portion 2 and lower ends coupled together to the receiver seat 7. With this arrangement, since the arms 18a, 18b are formed in a substantially Y- or V-shape, a hot air stream produced by a fire and coming closer in a direction of the arm 18a or 18b toward the glass bulb 15 passes through a void 19a or 19b defined in the arm 18a or 18b and contacts the glass bulb 15 to heat it without being undesirably affected by the arm 18a or 18b. Also, for a hot air stream coming closer in a direction vertical to the drawing sheet of Fig. 5, an advantageous flow effect can be obtained because the arms 18a, 18b are inclined. It is thus possible to eliminate directionality in sensitivity of the heat sensitive member and hence improve a sensitivity thereof. Further, since the arms 18a, 18b cover the glass bulb 15 in a larger circumferential range, a function of protecting the glass bulb can be increased. The arms may be provided with at least one draft hole, like the first embodiment, such an arrangement representing a second embodiment of the invention. Next, test results of the conventional frame type sprinkler head shown in Fig. 14 and the sprinkler head of Figures 4 to 6 having the Y-shaped arms 18a, 18b are shown in TABLE 1 below. The test was conducted by setting each of the sprinkler heads in an atmosphere with temperature of 100 (°C) and wind velocity of 1.5 (m/s), and measuring a time constant of a curve plotted on condition that the horizontal axis represents time and the vertical axis represents temperature. Hot air stream sent in direction of arm Hot air stream sent in direction perpendicular to arm Conventional type 342.8 56.4 Embodiment 77.6 31.5 As is apparent from the values measured for the conventional type in TABLE 1, when a hot air stream is sent in a direction of the arm toward the glass bulb, the time constant value is about six times as large as the value resulted when a hot air stream is sent in a direction perpendicular to the arm toward the glass bulb. In other words, it is found that the sensitivity is remarkably different depending on directions and is much reduced for the hot air stream coming closer in the direction of the arm toward the glass bulb. By contrast, in the arrangement of Figures 4 to 6, the difference between the two measured values can be held down on the order of twice and, hence, directionality in sensitivity can substantially be eliminated. Although the body 1 is constructed by forming the arms 6a, 6b; 17a, 17b; or 18a, 18b in an integral structure with the flange 5 in the above Embodiments , it may be constructed by forming the arms 6a, 6b; 17a, 17b; or 18a, 18b as separate members. In this case, the body 1 may be constituted by threading respective upper end portions of the arms 6a, 6b; 17a, 17b; or 18a, 18b, inserting the threaded portions into insertion holes bored through the flange 5, and fastening bolts or the like over the threaded portions, as with the prior art shown in Fig. 8, or by providing an annular tube at upper ends of the arms 6a, 6b; 17a, 17b; or 18a, 18b so as to interconnect the pair of arms, threading an inner (or outer) peripheral wall of the annular tube and an outer (or inner) peripheral wall of the flange, and fixedly screwing the arms to the flange through the threaded portions. While the foregoing illustrative Embodiments are described as applying the present invention principally to frame type sprinkler heads using heat sensitive members formed of glass bulbs, the present invention can also be applied to other frame type sprinkler heads using low melting-point alloys or the like.

Claims: A sprinkler head comprising: a body (1) having a water discharge port (3) formed at the center thereof, a valve (10) for opening and closing the water discharge port (3) of said body (1), a receiver seat (7) provided in a position opposing said valve (10), a heat sensitive member (15) disposed between said valve (10) and said receiver seat (7) for supporting said valve (10), said heat sensitive member (15) being disintegrable when heated, causing said valve (10) to move away from the water discharge port (3) of said body (1), and a frame (6a, 6b) for supporting said receiver seat (7) with respect to said body (1) and for reducing directional dependency of said heat sensitive member (15) when exposed to a hot air stream to improve its sensitivity, characterised in that said frame (6a, 6b) includes a plurality of arms (6a, 6b) supporting said receiver seat (7), each arm having at least one draft hole (9a-9f) formed therein through which a hot air stream flows toward said heat sensitive member (15). A sprinkler head according to claim 1 wherein each of said arms (6a, 6b) has a plurality of draft holes (9a-9f). A sprinkler head according to claim 1 wherein each of said arms (6a, 6b) is formed into a Y-shape. A sprinkler head according to claim 1 wherein each of said arms (6a, 6b) is formed into a V-shape. A sprinkler head according to claim 1 wherein said frame (6a, 6b) is formed in an integral structure with said body (1). A sprinkler head according to claim 1 further comprising a seal packing (13) interposed between said body (1) and said valve (10). A sprinkler head according to claim 6 wherein said seal packing 13 is made of a fluororesin. A sprinkler head according to claim 1 wherein said heat sensitive member (15) is formed of a glass bulb. A sprinkler head according to claim 1 further comprising a deflector (16) fixed to said frame (6a, 6b).

Inventors: TATENO YUKIO, TATENO, YUKIO, Tateno, Yukio, c/o Nohmi Bosai Ltd.
Applicants: NOHMI BOSAI LTD, NOHMI BOSAI LTD.
Application year: 1995
Main classification: A62C37
IPC codes: A62C37