MXPA00004104A - Latching solenoid valve - Google Patents

Abstract

A pilot valve is operated by solenoid formed by a coil (52) wound around a non-magnetic spool that has a bore (56). A rare earth permanent magnet (62) is inside the bore adjacent one end and abuts a flux concentrator (58) farther inside the bore. A plunger (68) is slidably located within the bore biased away from the flux concentrator by a spring (70) and projects out another end of the bore. An enclosure of magnetic material completes a magnetic flux path around the solenoid and has an aperture through which the plunger projects. The pilot valve includes a cage (86) of rigid non-magnetic material which abuts the enclosure and has a recess which supports the plunger out of contact with the housing. The plunger selectively opens and closes a pilot tube (92) through the cage to operate a diaphragm (100) that responds by engaging a primary valve seat to control the flow of fluid through a valve body.

Description

SOLENOID HITCH VALVE Field of the Invention The present invention relates to solenoid operated valves; and more particularly to such valves with latching type solenoid actuators.

Background of the Invention In hospitals, public restrooms and other facilities, it is desirable to provide the basin tap that turns off automatically after a given period of time, so that the water will no longer run indefinitely if the user does not close the key. Conventional spouts for this type of operation are typically referred to as "metering taps" and are mechanically operated by a piston.When the piston is moved by the user to open the valve, a variable chamber inside the valve Expands and fills with air or water.After being released by the user, the piston moves due to the spring force and decreases the size of the chamber to a REF .: 119941 speed that is governed by the release of air or water through a dosing orifice. This restricts the speed at which the spring force moves the piston to close the valve and thus the period when water flows from the spout. Among the drawbacks with such mechanical spigot is that in which the mechanical parts wear out with repeated use and the dosing orifice becomes clogged, eventually requiring either replacement or periodic adjustment and cleaning to ensure that the valve remains open for a period of time. of satisfactory time for the user to wash. As an alternative to these automatic, mechanical spigots, electrically controlled solenoid valves have been proposed. However, a conventional solenoid valve remains open only while an electric current is applied to an electromagnetic coil of the solenoid actuator. After removal of the electric current, a spring forces the solenoid to close the valve. As a result, solenoid valves use a considerable amount of electricity which makes them impractical for battery-powered operation. Therefore, energy is typically supplied from the building's electrical wiring, thus requiring an electrical outlet below the sink and protection so that the user does not receive an electric shock in the event of a circuit failure.

Brief Description of the Invention A general objective of the present invention is to provide a latching type solenoid actuator. Still another object is to provide such a latching solenoid valve with a permanent magnet located within an electromagnetic coil. A further objective of the present invention is to provide such a valve, which is capable of being energized by a battery, for a relatively long period of time between the replacement of the battery. These and other objectives are satisfied by a latching solenoid which has a spool of non-magnetic material with a hole. A solenoid coil is wound onto the reel to form an electro-agneto that produces a magnetic field when an electric current flows through the coil. A permanent magnet is located inside the reel hole together with a magnetically permeable material flow concentrator. A plunger is slidably positioned within the hole and projects axially outward from the spool. A housing of the magnetically permeable material encloses the spool and has a first member that already contacts the permanent magnet or the flow concentrator. A second member of the housing has an opening through which the plunger extends without contacting the second member, to minimize the effects of friction on the plunger. The solenoid operates a control valve mechanism that includes a cage of non-magnetic material that engages the housing and has a recess that receives and supports one end of the plunger. The cage includes a control tube which has a passage having a first opening in the recess with a seat of the control valve around that first opening.

A valve body is coupled to the housing and has an inlet and an outlet. The inlet communicates with the outlet through an opening and a primary valve seat extends around that opening. An elastic diaphragm selectively engages the primary valve seat to close the opening. The flexible diaphragm has a passage from side to side within which the control tube is tightly received.

Brief Description of the Drawings FIGURE 1 is a cross-sectional view through an automatic self-closing cock, incorporating a latch solenoid valve according to the present invention; FIGURE 2 illustrates the valve and pipe sub-assembly of the spigot; and FIGURE 3 is a cross-sectional view of the latching solenoid valve.

Detailed description of the invention With initial reference to FIGURE 1, the tap 10 has a hollow body 12 with a spout 14 projecting up and away from the main portion 13 of the hollow body. The body has a base plate 16 adapted to be mounted on the surface of a sink or on a back cover adjacent to a sink. The upper portion of the hollow body 12 has a cylindrical opening 15 which receives an actuator assembly 18 with a movable upper cover 20, which is slidably held in place by a screw 17 which enters a notch 19 in the core 21 of the actuator assembly. The actuator assembly 18 contains a battery 22 which is held against a pair of electrical contacts 24 and 26 by the cover 38 attached to the mounting body 21 by another screw 39. The upper cover 20 and the cover 38 can be easily removed to replace the battery without having to disconnect the tap 10 from the water supply, or having access to the components below the surface on which the tap is mounted. The printed circuit board 28, located 'inside the body 12, receives the electric current coming from the battery via the battery contacts 24 mounted on it. A housing 49 encloses the printed circuit board 28 providing protection against moisture damage, and the screw 53 which retains the housing in place also secures the actuator assembly 18 to the body 12 of the faucet. The printed circuit board 28 contains a timer or synchronizer circuit 29 and an electrical switch 32 for triggering the timer circuit. A switch push rod 34 extends downwardly through the actuator assembly 18 just below the inner surface of the top cap 20 to the switch 32 on the printed circuit board 28. A spring 36 also deflects the cap upper 20 away from the cover 38 and makes contact with the push rod 34 of the switch. The electrical output of the synchronizer or chronometer circuit 29 drives a solenoid valve 30 within the housing 12 of the faucet. The solenoid valve 30 is connected to a water inlet pipe 4 0 extending downwardly through the base plate 16 of the faucet 10. An accessory 33 at the remote end of the inlet pipe 40 contains a filter ( not shown) which traps particles that could plug the openings of the solenoid valve 30. A tube 42 projects from the solenoid valve 30 through the housing spigot 14 to an outlet fitting 41 on which it engages. threadedly an aerator 44. The solenoid valve 30, the inlet tube 40, the spout tube 42 and the outlet fitting 41 form an integral plumbing sub-assembly 45, as apparent from Figure 24 which is nested within of the hollow body 12 of the tap 10 shown in Figure 1. The water flows only through the plumbing sub-assembly 45 and does not come into contact with the body 12 of the tap. The plumbing sub-assembly 45 is prefabricated and then inserted as a unit through the open bottom of the faucet body 12. During insertion, the spout tube is pushed upwardly into the spout 14 until the outlet fitting 41 of the sub-assembly is aligned with an opening 47 in the lower part of the remote end of the spout 14. The aerator 44 is then screwed onto the outlet fitting through opening 47 of the spout. The solenoid valve 30 is pushed in an upward direction until a flat beveled surface 43 borders the housing 49 enclosing the printed circuit board 28. Securing the base plate 16 through the bottom opening of the hollow body 12 is retained the plumbing subassembly 45 in place with the inlet tube 40 projecting downwardly through the base plate. This procedure is reversed to remove the sub-assembly of plumbing 45, for repair or replacement. As will be described in more detail below, the top cap 20 is pushed in a downward direction by a user to activate the tap. That movement of the actuating cap 20 presses the push rod 32 downwards, closing the switch 32 and activating the chronometer circuit 29 on the printed circuit board 28. While the synchronizer or chronometer circuit is active, the solenoid valve 30 is in an open state, allowing water from the inlet tube 40 to flow through the aerator 44.

With reference to FIGURE 3, the solenoid valve 30 comprises a latching solenoid actuator 50 having an outer housing 51 enclosing an electromagnetic coil 52 wrapped around a spool 54 of non-magnetic material, such as a plastic. The outer housing 51 is made of steel or other magnetically permeable material. The spool 54 has an internal bore or diameter 56 that extends centrally therethrough within which a metal, cylindrical flow concentrator 58 is received which has an annular groove with an O-ring 60 therein. The flow concentrator 58 is surrounded by the solenoid coil or iobine 52. A permanent magnet 62 borders one end of the flow concentrator 58 and is adjacent an outer end of the orifice 56. The flow concentrator 58 and the o-ring 60 seal the hole in the spool 54, so that the water in a lower portion of the valve does not reach the magnet 62. As a consequence, a magnet or magnet of the rare earths can be used, which provides a relatively significant magnetic force. for its size. A pole piece 64 is threadably engaged within an integral accessory 66 of the solenoid housing 51 and retains the magnet or magnet 62 within the bore of the spool against the flow concentrator 58. The pole piece 64 may be axially adjusted during assembly to compensate for the manufacturing tolerances of the associated components. A plunger 68 of stainless steel is slidably positioned within the bore 56 of the spool on the opposite side of the flow concentrator 58 from the magneto or permanent magnet 62, and is diverted away from the flow concentrator by a spring 70. The remote end of the piston 68 has a recess with an elastic seal 72 captured therein. This remote end of the plunger 68 projects outwardly from an inner end of the reel 54. That end of the reel 54 has a flange 74 extending outwardly, with an annular recess 76 extending around the opening of the reel. hole 56 of the spool. A cylindrical rim 78 of an end cap 80 of the magnetically permeable material, such as stainless steel, is received within the recess 76 and is sealed there under pressure by a second O-ring 82. The open end of the housing 51 is pleated around the edge of the recess. the end cap 80, which completes the closure for the solenoid driver 50. An opening, which extends through the cylindrical rim 78, has a diameter that is slightly larger than the outer diameter of the plunger 68, which projects through it, thereby forming a magnetic flux free space 69. This results in the plunger 68 being able to move axially without contacting the end cap 80. The end cap has a second tubular projection 84 of larger diameter that extends outwardly from the opposite side. The pole piece 64, the outer housing 51, the end cap 80, the plunger 68 and the flow concentrator 58 create a magnetic flux path for the permanent magnet 62 and the electromagnet formed by the coil 52. This flow path has a free space 96 of constant magnetic flux, between the plunger 68 and the end cap 80, and a free space 67 of variable magnetic flux between the flow concentrator 58 and the plunger 68. The size of the variable magnetic flux free space changes according to the The plunger moves within the hole 56, as will be described later. A plug-shaped cage or grid 86, made of rigid non-magnetic material such as plastic, has a closed end received within an opening of the second end cap projection 84, to create a cavity 85 therebetween. This cavity 85 is partially defined by a recess 90 in the cage 86 that receives the remote end of the plunger 68. The internal diameter the hollow 90 closely engages the outer diameter of the plunger 68 to guide the axial movement of the plunger while keeping the outer surface of the plunger separate from the magnetically permeable end cap 84. A third O-ring 88 provides a seal between the cage 86 and the end cap 80. A spill hole 87 provides a fluid passage from the cavity 85 through the cage 86. The cage 86 has a control tube 92 that it projects in a downward direction beyond an open flange 94 of the end cap 80. An aperture 96 through the control tube 92 has a raised opening facing the plunger 68., whereby a control valve seat 98 is provided. The seal 72 of the plunger engages this seat 98 of the control valve when the solenoid valve 30 is at the closed end, as will be described later. A diaphragm 100 of elastic material, such as rubber, extends through the open edge or flange 94 of the cage 86, forming a pilot or control chamber 115 therebetween, and is retained by it in place. The periphery of the diaphragm 100 is compressed between the cage 86 and a valve body 102 which is threaded onto the end cap 84. The diaphragm 100 has a central opening 104 through it and the control tube 52 of the end cap is adjusted tightly inside that centxal opening. A centxal portion 106 of the diaphragm 100 resides in an inlet 114 within the valve body 102y and has a spill opening 107 therethrough. In the closed state of the latch solenoid valve 30, the central portion 106 of the diaphragm 102 borders a main valve seat 108 formed around an opening of an outlet 110 from the inlet 114 to the spout tube 42. The water pressure at the inlet 114 is communicated through the spill opening 107, so that the pressure in the cavity 85 behind the diaphragm 100 is greater than at the outlet 110, thereby maintaining the opening between the inlet and the outlet in valve seat 108, closed. In the closed state of the solenoid valve 30, the plunger 68 is held against the seat 98 of the control valve in the opening of the control tube 92 by the spring force 70 and any pneumatic or hydraulic force present, thereby the piston seat 72 closes that opening. The ejected axial magnetic force for pulling the plunger 68 towards the permanent magnet 62 is determined by the length of the i-ix-e space 67 of the variable magnetic flux between the flow concentrator 58 and the plunger, as well as the flux density in that free space of magnetic flux. That magnetic force is diminished by making the free space 67 of magnetic flux larger, or the density of flow smaller. The design of the plunger 68, the flow concentrator 58 and the permanent magnet 62 cause the free-space flux density to drop rapidly as the length of this free space increases. In the closed position of the plunger 68, the variable magnetic flux clearance 67 is sufficiently large such that the axial magnetic force exerted by the permanent magnet 62 is minimized, and can not exceed the spring force. In this way, the plunger is engaged in the closed position in the absence of electric current flowing through the coil 52. A substantially constant free magnetic flux space 69 exists in the magnetic flux path between the plunger 68 and the end cap. 80. The magnetic flux in this free space creates a radial force on the plunger which can cause undesirable friction which impedes the axial movement of the plunger 68. Theextensive material has the effect of this frictional force in supporting the adjacent end of the plunger. plunger 58 on the plastic cage 86. This support holds the piston almost centered in the space lii >; re 69 magnetic flux, which minimizes radial force and provides low friction, low wear surface against which the plunger slides. By supporting the plunger with the plastic spool 54 and the plastic cage 86, the constant magnetic flux clearance 69 can be made relatively small, which improves the efficiency of the latching solenoid actuator 50.

When a user presses the upper cap 20 of the actuator assembly 18, the chronometer circuit 29 is activated and applies a brief pulse of electrical current to the electromagnetic coil 52. The duration (for example, 0.025 seconds) of this pulse is just enough prolonged so that the coil 52 generates an additional magnetic field of the same polarity as the permanent magnet 62, which pulls the plunger 68 farther into the bore 56 of the spool of the coil and away from the seat 98 of the control valve in the opening of the control tube 92, as illustrated in FIG. 3. The current pulse is sufficiently intense so that the plunger 68 strikes the flow concentrator 58, thereby eliminating the magnetic flux clearance 67 in the magnetic flux path, and thereby maximizes the force from the permanent magnet 62. This permanent magnetic force is sufficient by itself to overcome the spring force 70 and retain the piston away from the opening of the control tube "92. In other words, the force from the permanent magnet 62 is now greater than the spring force. Therefore, the plunger is engaged in the open state by the permanent magnet 62 at the end of the electrical pulse from the synchronizing circuit 29, at which point the magnetic field produced by the coil 52 is terminated. The stroke distance of the plunger is kept relatively short to minimize the energy required to move the plunger between the extreme positions of its travel. This stroke of the plunger is adjusted by moving the pole piece 64 in and out of the bore 56 of the spool. As the plunger 68 moves away from the seat 98 of the control valve, the cavity 85 of the cage opens within the control passage 96 which communicates with the spout tube 42. This relieves pressure from within the cavity. 85 and inside the control chamber 115 behind the diaphragm 100, via the spill hole 87. With that pressure released, the pressure within the inlet 114 forces the diaphragm 100 away from the main valve seat 108 that opens a passage between the inlet and the spout tubes 40 and 42. This allows water to flow through the valve and out of the aerator 44. When the open period of the valve (e.g., three to eleven seconds) elapses, the synchronizing circuit or of chronometer 29 automatically sends another pulse of electrical current through the electromagnetic coil 52 in the opposite direction to that of the first current pulse, thereby producing a magnetic field of polarity opposite to aq. The permanent magnet circuit 62. The chronometer circuit also generates that pulse when the user operates the switch 32 by pressing the end cap 20, while the solenoid valve closes. This pulse produces an electromagnetic field, which substantially cancels the permanent magnetic juncture, allowing the spring to force the plunger 68 out of the spool 54 and against the cage 86, closing the control passage 96. That movement also increases the clearance 67 of variable magnetic flux between the flow concentrator 58 and the plunger, so that at the end of the electrical pulse when the electromagnetic field that forces the permanent magnet ends, it is reduced to less than the spring force. As a result, the spring 70 holds the plunger in the closed state. With the plunger 68 sealed against the control valve seat 98 in the opening of the control tube 96, the pressure in the control chamber 115 below the diaphragm 100 becomes greater than the pressure at the outlet 110. As a result of this differential of pressure, the diaphragm 100 is forced against the seat 108 of the main valve, thereby closing the passageway between the inlet and the spout tubes 40 and 42. The diaphragm 100 is held in this position until the pressure it is matched by the plunger 68 once again moving away from the seat 98 of the control valve. Because the plunger 68 engages the rigid cage 86 to close the control passage, it does not apply force directly to the diaphragm 100. In this way, this results in a smoother and quieter diaphragm operation.

It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers.

Claims (9)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A coupling solenoid valve, characterized in that it comprises: a solenoid having an orifice or internal diameter and a coil for producing a magnetic field when an electric current flows through it; a permanent magnet located inside the hole; a flow concentrator of magnetically permeable material located within the orifice; a plunger of magnetically permeable material slidably positioned within the hole and projecting outwardly from the solenoid; a housing of magnetically permeable material containing the solenoid and having a first member contacting one of the permanent magnet and the flow concentrator, and a second member with an opening through which the piston extends; a cage of non-magnetic material coupled to the casing or housing, and having a recess within which is received and supported one end of the plunger, the cage including a control tube with a first opening within the recess and with a second opening, the cage having a control valve seat around the first opening, and a spill hole extending through the cage from the cavity; a valve body coupled to the housing and having an inlet and an outlet communicating through an opening with the inlet, wherein a primary valve seat extends around the opening; and an elastic diaphragm cooperating with the end cap to form a chamber within which the spill orifice is communicated, and which responds to pressure within the chamber by selectively coupling the primary valve seat to close the opening, the elastic diaphragm has a control opening which communicates with the outlet and into which the control tube is received.

2. The coupling solenoid valve according to claim 1, characterized in that the solenoid comprises a reel formed of non-magnetic material around which the reel is wound.

3. The coupling solenoid valve according to claim 1, characterized in that the piston has an elastic seal which is selectively coupled to the seat of the control valve.

4. The coupling solenoid valve according to claim 1, characterized in that the flow concentrator includes a seal that prevents fluid from flowing through the orifice beyond the flow concentrator.

5. A coupling solenoid valve, characterized in that it comprises: a housing of magnetic material having an open end and a closed end with a threaded opening; a pole piece is screwed into the threaded opening; the spool formed of non-magnetic material within the housing and having a hole; a solenoid coil wound on the spool to produce a magnetic field when an electric current flows through it; a permanent magnet located inside the hole of the reel and that borders the pole piece; a flow concentrator of magnetically permeable material located inside the hole of the reel abutting the permanent magnet; a plunger of magnetic material slidably placed within the bore of the spool and projecting outwardly from the spool; a spring that diverts the plunger away from the flow concentrator; an end cap of magnetic material that engages the housing and encloses the open end, the end cap having an opening through which the plunger extends without contacting the end cap; a cage of rigid non-magnetic material, coupled to the end cap and having first and second opposite sides with the first side having a hollow inside which is received and supported one end of the plunger, the cage including a control tube having a control valve seat at one end that opens toward the recess and having a second end, the cage further includes a spill hole extending between the recess and the second side; a valve body coupled to the housing and including an inlet and outlet in communication through an opening with the inlet, wherein a primary valve seat extends around the opening; and an elastic diaphragm adjacent the second side of the cage to form a control chamber therebetween, and which responds to pressure within the chamber by selectively coupling the primary valve seat to close the communication between the inlet and the outlet , the elastic diaphragm has a control opening into which the control tube is received, wherein the second end of the control tube communicates with the outlet.

6. The coupling solenoid valve according to claim 5, characterized in that the spring is inside the bore of the spool.

7. The coupling solenoid valve according to claim 5, characterized in that the permanent magnet is a magneto of the rare earths.

8. The coupling solenoid valve according to claim 5, characterized in that the piston has an elastic seal that is selectively coupled with the seat of the control valve.

9. The coupling solenoid valve according to claim 5, characterized in that the flow concentrator includes a seal that prevents fluid from flowing through the orifice beyond the flow concentrator. SOLENOID HITCH VALVE SUMMARY OF THE INVENTION A control valve is operated by the solenoid formed by a coil (52) wound around a non-magnetic spool having a hole (56). A permanent magneto (62) of the rare earths is inside the hole adjacent to one end, and borders a flow concentrator (58) beyond the orifice. A plunger (68) is slidably positioned within the hole, diverted away from the flow concentrator by a spring (70), and projects out of another end of the hole. A casing or housing of magnetic material completes a magnetic flux path around the solenoid, and has an opening through which the plunger projects. The control valve includes a cage (86) of rigid non-magnetic material that borders the envelope and has a recess that supports the plunger out of contact with the housing. The piston selectively opens and closes a control tube (92) through the cage to operate a diaphragm (100) that responds by coupling a primary valve seat to control the flow of fluid through the valve body.