MXPA97001167A - Electromagnetic regulating valve for fluid circuit, in particular gaseous - Google Patents

Abstract

Electrically operated regulating valve for gases used in heating and cooking apparatus The valve (2) has a body which has an inlet channel (3) leading to an internal chamber (4) which contains a valve seating (7). A short conduit (6) connects the valve seating (7) to an outlet (5). An electromagnet (8) is located above the body of the valve (2). The electromagnet (8) has a variably pulsed winding (9) wound on an insulating frame (10) and actuates a spring loaded (21) rod armature (20) through a magnetic circuit consisting of two opposed tubular elements (11,12). The lower end of the rod armature has an elastic fitting (23) which makes contact with the valve seating (7) when the valve is closed or an upper stop surface (26) when it is open.

Description

SOLENOID VALVE TO REGULATE THE FLUID OF FLUIDS IN CIRCUITS, WITH SPECIAL APPLICATION IN GAS CIRCUITS BACKGROUND OF THE INVENTION This invention concerns a solenoid valve for regulating the flow of fluids in a circuit, with special application to gas circuits, more specifically to a pulsed solenoid valve piloted by a square electrical signal with a variable cyclic relationship and a fixed or variable frequency, the output rate of the valve being proportional to the cyclic relationship. This flow regulating solenoid valve has special application in gas-powered domestic appliances, such as domestic appliances for cooking or heating, where it controls the flow of gas to the burners. Such flow regulating solenoid valves in gas burner control applications must work at relatively high temperatures; moreover, in the type of application mentioned above, they must be able to pass through a large number of cycles, in the order of several hundred million. A silent operation is also desirable. The above objectives are not completely satisfied by known flow regulating solenoid valves. Specifically, it should be noted that in known solenoid valves, the magnet-driven moving assembly, which includes the moving cylindrical core, as well as a shutter cooperating with a fixed seat, in most cases are relatively massive This set moves back and forth to the frequency of the electrical pulses that pilot the solenoid valve; and produces internal noise-generating impacts in the course of the operation. Specifically, an impact may occur each time the oscillating assembly reaches the end position farthest from the fixed seat, when the core that is "moved" enters. in direct contact, not absorbed with your guide. In addition to undesirable noise, such impacts cause wear and tear of the solenoid valve, which shortens its life. SUMMARY OF THE INVENTION The objective of this invention is to provide a flow regulating solenoid valve for fluid circuits, with special application in gas circuits, which, despite its very simple structure, eliminates internal impacts 'and most of the operation noise, and in this way it offers increased reliability and life, in addition to operation practically silent. The object of the invention is a solenoid valve for regulating the flow of fluids in circuits, with special application in gas circuits. More specifically, it is a pulsed solenoid valve with a variable cyclic relationship, presenting a body with a fluid inlet gate, a fluid outlet gate, and an internal chamber. One of the gates is connected to said chamber via a short channel, the output end of which forms an annular seat. The valve also includes an electromagnet with a coil and a fixed magnetic circuit mounted around a central guide with a cylindrical recess opening to the internal chamber. The recess houses a magnetic core in motion, retracted by a return spring. One end of the moving magnetic core includes a skirt designed to cooperate with the annular seat. The solenoid valve is defined by the fact that an end face of the skirt, which is made of an elastic material, is more or less circular or annular in shape, and cooperates with the annular seat when the solenoid valve is closed; while the other end face of the skirt, which faces in the opposite direction, meets the wall of the internal chamber opposite the annular seat when the solenoid valve is in the open position. In this way, a defining characteristic of the invention is that the end position of the moving core, which corresponds to the open position of the solenoid valve, is achieved by the stop of a part made of elastic material, i.e. skirt in the moving core, and not by the stoppage of rigid parts or by the return spring, as is usually the case. This eliminates impacts and noise, as well as excessive spring wear.

In a preferred embodiment of the invention, the central guide, in the recess from which the moving core oscillates, includes an end flange attached to the body by the solenoid valve. This tab constitutes the limit of the internal chamber mentioned above. The assembly is designed so that when the solenoid valve is closed, the annular end face of the skirt faces one of the faces of the end flange of the central guide. Furthermore, it is advantageous to give the moving core of the flow regulating solenoid valve according to the invention an elongated, approximately cylindrical shape, with one of its ends shaped like a head on which the skirt is mounted and retained. In this way, the set that moves is of limited mass. The invention will be further elucidated by the following description, which refers to the attached schematic drawing of an example of an embodiment of the flow regulating solenoid valve for fluid circuits, with special application in gas circuits. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a general view, in longitudinal cross-section, of a solenoid valve according to the invention; Figure 2 is a skeleton diagram showing the mechanical operation of the solenoid valve of Figure 1, in the open position; Figure 3 is a skeleton diagram similar to Figure 2, but showing the solenoid valve in the closed position. Detailed Description of the Invention Figure 1 shows a flow regulating solenoid valve for a gas circuit, with most of its components arranged along a central axis 1. The solenoid valve includes a body 2, with a gate side of ^^ 0 gas inlet 3, opening towards the internal chamber 4 of the body 2, and an axial gas outlet gate 5. The outlet gate 5 is connected, via a short axial channel 6, to the center of the internal chamber 4 , and an annular seat 7 is formed at the point where the channel 6 enters said internal chamber 4. The electromagnet of the solenoid valve indicated generally 8 is placed on the body 2 of the valve. This electromagnet includes an excitation coil 9, wound around an insulating housing 10, which itself surrounds a fixed magnetic circuit constituted by two opposite tubular components 11 and 12. Electrical terminals 13, energizing the excitation coil 9, they are mounted on the housing 10. The assembly constituted by the coil 9, the housing 10, and the magnetic circuit 11, 12 is arranged around a central guide 14, one end of which is enlarged towards an end flange 15 which it rests against the body 2 and is attached to it by means of screws 16. An annular gasket or seal ring 17 is inserted between the flange and the body. The other end of the guide 14 includes an elastic retaining ring 18, which rests against the component 12 of the fixed magnetic circuit. The guide 14 includes, in part of its length, a cylindrical recess or perforation 19 opening to the internal chamber 4, k opposite the annular seat 7. The moving magnetic core 0 20, which is elongated, approximately cylindrical , is mounted within the recess 19 of the guide 14. A return spring 21, housed and compressed in the "bottom" or upper end of the recess 19, pushes one end of the moving core 20 towards the body 2. 5 another end of the moving core 20 is located within the inner chamber 4, and is profiled in the shape of a head 22. The elastic skirt 23 is assembled and retained in the head 22 of the moving core 20. The exterior of the skirt 23 is of approximately cylindrical shape; in this way, it has a circular end face 24 (facing the annular seat 7) and, on the opposite side, an annular end face indicated generally at 25, turned towards a face 26 of the end flange 15 of the guide 14, the face 26 marking the limit of the internal chamber 4. 5 When the solenoid valve is in the closed position (which is also the rest position), the moving core 20 is pushed "backwards" or down by the spring back 21; and the circular end face 24 of the skirt 23 forms a seal against the annular seat 7. In this position, the gas inlet gate 3 and the gas outlet gate 5 are completely isolated from each other (see figures 1 and 3) . When the solenoid valve is in the open position (Figure 2), the moving core 20, attracted by the electromagnet 8, is pulled more deeply into the recess 19, which further compresses the return spring 21 and raises the skirt 23 away from the annular seat 7. In this position, the gas inlet gate 3 and the gas outlet gate 5 communicate with each other via the internal chamber 4. An important feature of the solenoid valve according to the invention is the fact that, in the open position, the end face 5 of the skirt 23 rests against the face 26 of the end flange 15 of the guide 14, and there is no contact between the moving core 20 and the wall of the guide. recess 19 of the guide 14. When the flow regulating solenoid valve is in operation, the moving core 20 moves back and forth between closed and open positions, cyclically and at a given frequency that depends on the electric pulses. icos sent to the excitation coil 9. Specifically, such pulses can # be of cyclic ratio or variable duty cycle (duration of each pulse / cycle period), while the frequency itself is fixed and of a value in the range of 20 to 25 Hz, for example. The cyclic relationship or work cycle can also vary in a range of 0 to 100%; and the gas flow rate at the solenoid valve outlet gate is proportional to the value of the duty cycle or cyclic ratio, since this ratio is also the time during which the solenoid valve is open during the period of the cycle. * 0 While the moving core 20 moves back and forth between closed and open positions, the skirt 23 alternates, between stops against the annular seat 7 (via its circular end face 24) and the end flange 15 of the guide 14 (via its annular end face 25). As the skirt 23 is made of synthetic rubber 5, it absorbs to a considerable extent the impacts produced by the moving assembly (the moving core 20 plus the skirt 23) against both the annular seat 7 and the guide 14, of this way eliminating noise. The severity of the impacts in this case is further weakened by the low or mass of the moving assembly driven by the electromagnet 8. The scope of the invention is not limited to the sole example of an embodiment of the flow regulating solenoid valve that it has been described above, but it encompasses all the variants and possible applications that use the same principle.

# Specifically, changes may be made in the construction details of the valve, or in the materials used, or the same flow regulating solenoid valve may be used in a liquid circuit, without departing from the scope of the invention. * ?

Claims (4)

1. CLAIMS 1. Solenoid valve to regulate the flow of fluids within a circuit, with special application in gas circuits, specifically a solenoid valve pulsed with a variable cyclic ratio, including a body with a fluid inlet gate, a gate of fluid outlet, and an internal chamber, one of the gates being connected to the internal chamber via a short channel with an annular seat at the point where it enters the chamber; also including an electromagnet with a coil and a fixed magnetic circuit, mounted around a central guide with an approximately cylindrical recess opening towards the aforementioned internal chamber and housing a core that moves subject to the pressure of a return spring; one end of the moving core includes a skirt designed to cooperate with the annular seat; said valve is defined by the fact that the skirt, which is made of an elastic material, includes a first approximately circular or annular end face which cooperates with the annular seat when the solenoid valve is in the closed position, and a second end face approximately annular, on the opposite side of the preceding one, which comes to rest against the wall of the inner chamber, at the end opposite the annular seat, when the valve is in the open position.
2. 2. Solenoid valve for regulating the flow of fluids within a circuit, according to claim * 1, defined by the fact that the central guide, in the recess in which the moving core oscillates, includes a flange of end that rests against and is fixed to the body, and constitutes the limit of the aforementioned internal chamber; and by the fact that the annular end face of the skirt comes to rest against the wall of the end flange of the guide when the solenoid valve is in the closed position.
3. 3. Solenoid valve for regulating the flow of fluids within a circuit, according to claim 1, wherein the moving core is of an elongated, approximately cylindrical shape, with one end profiled to form a head in the which is mounted and retains the skirt.
4. 4. A solenoid-operated valve assembly of the type operated by a variable-width, fixed-frequency pulse electrical signal, comprising: (a) a coil surrounding tubular pole pieces and a valve guide with a valve member. magnetic, movable valve, movably received in it; (b) an elastomeric, resilient cap disposed at one end of said valve member, said lid operable upon movement of the valve member in a first direction to close against a valve seat and upon movement of said valve member in a second direction opposite said first direction for opening said valve seat and contacting said guide, thereby limiting the movement of said valve member in said second direction; and (c) means biasing said valve member in said direction, wherein said valve member is moved between said first and second positions upon operation of said coil with said variable width pulse signal.