CLIAMS:We claim:
1.An energy efficient solenoid valve comprising of a solenoid coil, plurality of springs, plurality of ports, characterized by an electrical pulse operated solenoid coil, a plunger, a spool, a hollow bush and one or more spherical ball, interdependent locking of the plunger and the spool to achieve latching and mechanical de-latching;
to latch, the electrical pulse operated solenoid coil is energized for pre-determined short time, the plunger having trapped one or more substantially spherical ball in a recess of the hollow bush, the spherical ball gets displaced outwards by the spool and force of a spool-spring when the solenoid coil is energized and the plunger gets pulled, releasing the spool from an inward to an outward situation due to force of the spool-spring, the spool in-turn locking the spherical ball in a second position and thus latching the plunger, thereby connecting an inlet port and an outlet port; and
disconnecting of the inlet port and the outlet port by mechanical displacement of the spool from the outward to the inward situation, displacing a flat face of the spool, the spherical ball returning to a first position and getting trapped, causing the de-latching of the plunger, the outlet and an optional exhaust port thus optionally connected, connection between the ports insulated by plurality of flexible seals.

2.The energy efficient solenoid valve as claimed in claim 1, wherein said plunger has a wedge construction at a distal end of the plunger.

3.The energy efficient solenoid valve as claimed in claim 1, wherein said spool has a tapered face and a flat face.

4.The energy efficient solenoid valve as claimed in claim 1, wherein diameter of said spherical ball, diameter of said recess of the hollow bush, linear and angular dimensions of said wedge construction of the plunger and linear and angular dimensions of said tapered face and said flat face of the spool are such that when the spherical ball touches the flat face of the spool, said edge of the wedge construction of the plunger rests on the spherical ball just above diametric width of spherical ball and spherical ball holds the plunger in pulled position , even when solenoid coil is NOT energized; and when the spherical ball touches the tapered face of the spool, the plunger can freely travel to and from the un-pulled position to pulled position.

5.The energy efficient solenoid valve as claimed in claim 1, wherein the tapered face of said spool causes an inward force due to a spool-spring, on said spherical ball, when the spherical ball is trapped in a first position.

6.The energy efficient solenoid valve as claimed in claim 1, wherein the edge of said wedge construction of the plunger causes an inward force due to the plunger-spring, on said spherical ball, when the spherical ball is locked in a second position.

7.The energy efficient high pressure solenoid valve as claimed in claim 1, wherein said mechanical displacement of the spool is by manually pulling the spool from a solenoid end to an inward situation.

8.The energy efficient solenoid solenoid valve as claimed in claim 1, wherein said mechanical displacement of the spool is by manually pushing the spool from a valve end to the inward situation.

9.The energy efficient solenoid valve as claimed in claim 1, wherein said mechanical displacement is by pushing the spool by an auto-returning rotary cam.

10.The energy efficient solenoid valve as claimed in claim 1, wherein said mechanical displacement is by pushing the spool by applying fluid pressure through an inlet.

11.Energy efficient high pressure solenoid valve substantially as hereinabove described in the specification with reference to the accompanying drawings.
,TagSPECI:
Form 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules 2003

Complete Specification
(See section 10 and rule 13)

Title of the Invention:
Energy Efficient Mechanically De-latchable Solenoid Valve

Applicant: M/s. ROTEX Manufacturers and Engineers
Private Limited

Nationality: Indian
Address: Manpada Road,
Dombivali (East) – 421204,
Maharashtra, INDIA

The following specification particularly describes the invention and the manner in which it is to be performed.
FIELD OF THE INVENTION
[0001] The invention relates to a valve for control of fluid flow. Particularly, the invention relates to a solenoid valve. More particularly, the invention relates to a solenoid valve with mechanical de-latching.

BACKGROUND
[0002] A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. In an open valve, fluid flows in a direction from higher pressure to lower pressure. Valves are found in virtually every industrial process, including water & sewage processing, mining, power generation, processing of oil, gas & petroleum, food manufacturing, chemical & plastic manufacturing and many other fields. Valves are also used for pneumatic controls.
[0003] Valves work on various mechanisms such as pressure controlled mechanisms, whereby pressure of the fluid determines opening and closing of valve as in patent no US3115330, US2894713. There are also valves that function on electrical means for closing and opening them as in patent no US5934313.Valves also operate by activating and de-activating electromagnetic coils as in patent no US775054, US2224147.
[0004] Solenoid valves are electromechanically operated valve. Such valves are controlled by an electric current through a solenoid as in publication no US2003042452A1, US2013248743A1, US2013264506A1.
[0005] Solenoid valves with latching mechanism are well known, as in patent publication no. EP1025379B1, EP1065418B1, and patent no US2632821, CA2304330.
[0006] The latching mechanism described in patent no US3463445 is a manually and electrically operable mechanism. There is a manual handle provided for opening and closing the valve and this manual action directly does not affect the valve but it is controlled via an intermediate member. This effect of the moment of the manual handle is directed to the intermediate by additional means like a solenoid. The latching is by the movement of the spring causing the wedging element to move the ball inside and outside the inner wall thereby latching and De-latching of the carrier and the sleeve and transmitting or preventing the transmission of the manual moment to reach the valve. Energizing and de-energizing of the solenoid aids the latching and de-latching of the valve. A continuous energizing of the solenoid is required for this invention, as also spring properties need to be precisely co-ordinated.
[0007] Patent no US3463443 describes use of two solenoids, connected to a safety device so as to prevent the opening of the solenoid valve until the safety device is closed. It works on the same mechanism where a stem is provided with a wedging element pushing a ball inside and outside a transverse opening radially leading to positioning and repositioning of the ball into a recess in the inner wall causing latching an Un-latching. Here there are two solenoids which work alternately by activation and deactivation in relation to the magnetic circuit.
[0008] Patent no US3385559 also describes the use of ball mechanism in presence of a wedging element for latching and de-latching, wherein the ball is slidable in a positional relationship with the other elements restricting the movement between the elements. The disclosure deploys complex mechanism and two solenoids.
[0009] Patent no US3463444 describes a valve which is controlled manually for opening, while the latching mechanism is controlled electrically by a solenoid. The latching and unlatching mechanism is controlled by a latching and un-latching spring. In this disclosure, precise force characteristic co-ordination is required between latching and un-latching spring, which is difficult to maintain, particularly over life of the product.
[0010] There are applications which need to open the valve with minimum electrical energy to release fluid, particularly, air, at high pressure, of the order of 100 bar and above; and which should need no electrical energy to keep the valve latched, as well as to de-latch. Moreover, de-latching is required to be reliable, and of different convenience. There is no such solenoid valve known, particularly robust and simple in construction for such application.
[0011] Our invention provides such solution.

OBJECT OF THE INVENTION
[0012] The objective is to invent a solenoid valve for control of fluid flow which requires minimum electrical energy in latched condition.
[0013] Another objective is to invent a solenoid valve which de-latches mechanically.
[0014] Yet another objective is to invent a solenoid valve which de-latches mechanically by manual action.
[0015] Yet another objective is to invent a solenoid valve which de-latches mechanically by fluid pressure.
[0016] Yet another objective is to invent a solenoid valve with simple, robust and positive latching and de-latching arrangement.

SUMMARY OF INVENTION
[0017] Our invention discloses mechanically de-latchable solenoid valve with electrical pulse operated solenoid coil. The electrical pulse operated solenoid coil needs electrical energy only for plunger of solenoid travelling from un-pulled to pulled position. A hollow bush inside plunger has one or more openings called recess. A substantially spherical ball is provided in the recess and space around the recess. The space around the recess is due to tapered face of spool on one side and wedge shape at the distal end of plunger on the other side. On supplying electric energy of rated voltage and requisite volt-amperes, the plunger travels from un-pulled position to pulled position. As the plunger completes the travel, the substantially spherical rigid ball gets un-trapped from recess. Previously, while trapped in the recess, the spherical ball is constantly pushed by tapered face of spool due to force from spool-spring acting on spool. Un-trapping of the spherical ball allows the spherical ball to move away from tapered face of spool to another position, called second position, due to tapered edge construction of the spool pushing away the spherical ball. The spool, in turn, owing to force of spool-spring, takes outward situation; causing inlet and outlet ports of valve to get connected, in other words, the valve is open and the fluid is allowed to flow from high pressure to low pressure.
[0018] The spherical ball is now locked in second position due to flat face of spool. In this second position, the spherical ball obstructs the plunger from returning back to un-pulled position. The plunger therefore, stay puts in pulled position, as if the solenoid coil is in “energized state” even while the electric energy is disconnected after pre-determined short time. At the same time, plunger continues to apply force on spherical ball due to force of plunger-springs acting on Plunger.
[0019] To disconnect the inlet and outlet ports, that is, to close the valve, the spool is mechanically assisted to move from outward situation to inward situation. Such movement of the spool from outward situation to inward situation causes displacement of the flat face of spool from in-front of the spherical ball, and the spherical ball is unlocked from second position. Force acting on spherical ball due to solenoid-springs pushes the spherical balls back to first position. Plunger travels back to un-pulled position, corresponding to “un-energized state” of solenoid coil.
[0020] The spool is mechanically assisted either by pulling from solenoid end or by pushing from valve end. The pull or push could be manual, whether linear or rotary; or by applying fluid pressure; or by vacuum.

BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure-1 shows sectional view of our inventive mechanically de-latchable solenoid valve with electrical pulse operated solenoid coil, when the plunger is in un-pulled position and the valve is close. Also it shows arrangement of mechanical movement of spool which is by manually pulling of spool.
[0022] Figure -2 shows close up sectional view of recess of hollow bush, tapered face of spool, spherical ball and wedge construction of plunger, when plunger is in un-pulled position. Un-pulled position of plunger corresponds to first position of the spherical ball.
[0023] Figure-3 shows sectional view of said solenoid valve, when the plunger in pulled position and the valve is open. Also it shows arrangement of mechanical movement of spool which is by manually pulling of spool.
[0024] Figure-4 shows close up sectional view of the recess of hollow bush, the tapered face of the spool, the spherical ball and the wedge construction of plunger, when plunger is in pulled position. Pulled position of plunger corresponds to second position of spherical ball.

[0025] Figure-5 shows sectional view of said solenoid valve, when the plunger is in un-pulled position and the valve is close, with another embodiment of mechanical spool movement which is by manually pushing of spool.
[0026] Figure-6 shows sectional view of said solenoid valve, when the plunger in pulled position and the valve is open; with another embodiment of mechanical spool movement, which is by manually pushing of spool.
[0027] Figure-7 shows generic view of a hollow bush with a recess.
[0028] Figure-8 shows generic view of plunger with wedge construction at its distal end.
[0029] Figure-9 shows spherical ball with position of edge of wedge construction of plunger when plunger is in pulled position.
[0030] Figure-10 shows generic view of spool, highlighting flat face and tapered face of spool, and projection.
[0031] Figure-11 shows insert-bush with plunger-springs.
[0032] Figure-12 shows sectional view of a typical 3-port valve.
[0033] Figure-13 shows Force diagram, of force on spherical ball due to tapered face of spool.
[0034] Figure-14 shows Force Diagram, of force on spherical ball due to edge of wedge construction of plunger.
[0035] Figure-15 shows sectional view of said solenoid valve, when the plunger in pulled position and the valve is open; with another embodiment of mechanical spool movement, which is by manually pushing of spool by an auto-returning rotary cam.
[0036] Figure-16 shows sectional view of said solenoid valve, when the plunger in un-pulled position and the valve is close; with another embodiment of mechanical spool movement, which is by pushing of spool by applying fluid pressure through inlet.

DETAILED DESCRIPTION OF INVENTION
[0037] The preferred embodiment of invention shall now be described with the help of drawings. However, the description should not be construed to limit the invention.
[0038] As shown overall in Figures-1,3,5,6 and other figures, our inventive mechanically de-latchable Solenoid Valve (10) with electrical pulse operated solenoid coil (14) has following significant parts, construction and fitment:
• A solenoid coil (14) with winding and core (not marked) with such known design parameters that an electric pulse of rated voltage and Volt-Amperes for a time period less than 200millisecond generates enough magneto-motive force to cause plunger (5) to travel rapidly with consistency from an un-pulled position (21) (Figure-2) to a pulled position (22) (Figure-4), against opposing force of one or more plunger-springs (7).
• A guide (16) of hollow cylindrical shape and made of non-ferromagnetic material. The guide (16) has a collar (19) at one end. The solenoid coil (14) is assembled by sliding over the guide (16) from a solenoid end ( 32) till the collar (19) . An insert-bush (3), made of ferro-magnetic material, is snugly fixed inside the guide (16). Insert-bush (3) has threaded construction (24) , as shown in Figure -11, at its projected end (23), and correspondingly, a threaded nut (2) is provided over threaded construction of insert-bush (3), such that threaded nut (2) holds the solenoid coil (14) pressed against collar (19) of guide (16). One or more plunger-springs (7) are firmly seated on the inside end (25) of insert-bush (3).
• As shown in Figure-7, a hollow bush (4) , firmly attached to inside end (25) (Figure -11) of insert-bush (3). One or more recess (17), which is essentially a through hole in the wall of hollow bush (4) are provided.
• Plunger (5), which is cylindrical and hollow, has wedge construction (6) at its distal end (45), as shown in Figure-8. Plunger (5) is provided between guide (16) and hollow bush (4). Plunger (5) is of such external and internal diameters that it smoothly slides along the corresponding mating surfaces of guide (16) and hollow bush (4).
• On the other side of guide (16) is fitted a 3-port valve (35), significantly consisting of valve body (1) with inlet port (26), outlet port (27) and optional exhaust port (28) as shown in Figure-12.
• A piston like cylindrical part called spool (9), having provision for mounting at least three seals (18-1, 18-2, 18-3) , a flat face (29) and a tapered face (30) (Figure-10, 12) is axially provided inside the 3-port valve (35) such that the spool-head (9A) rests against a spool-spring (8). The Spool (9) can move from an inward situation to an outward situation. The inward situation corresponds to the spherical ball (20) touching the tapered face (30) of the spool (9), while the outward situation corresponds to the spherical ball (20) touching the flat face (29) of the spool (9).
• A substantially spherical ball (20) of rigid and non-ferrous material. Diameter of spherical ball (20), diameter of recess (17), linear and angular dimensions of wedge construction (6) of plunger (5) and linear and angular dimensions of tapered face (30) are such that :
o When the spherical ball (20) touches the tapered face (30) of the spool (9), which is notated as the spool (9) in inward situation, the plunger (5) can freely travel to and from an un-pulled position (21) to a pulled position (22). At the same time, there is an inward force FSS x Sin? (39) acting on the spherical ball (20), as shown in Figure-13. This position is also described as first position (41) of the spherical ball (20) and illustrated in Figure-2.
o When the spherical ball (20) touches the flat face (29) of the spool (9), which is notated as the spool (9) in the outward situation, the edge (36) of the wedge construction (6) of plunger (5) rests on the spherical ball (20) just above its diametric width (37) ( Figure - 9) and the holds plunger (5) in the pulled position (22), even when solenoid coil (14) is NOT energized. At the same time, the edge (36) causes an inward force FPS x Sina (38), as shown in Figure-14. This position is also described as second position (42) of the spherical ball (20) and illustrated in Figure-4.
[0039] When spool (9) is at the inward situation, seal (18-2) comes in-between inlet port (26) and outlet port (27) and thereby disconnects inlet port (26) from outlet port (27), which implies that the valve (35) is close. At this situation, seal (18-3) permits connection between outlet port (27) and optional exhaust port (28). Seal (18-1) insulates inlet port (26) from the valve end (31), thereby preventing pressure loss due to possible leakage from the valve end (31) (as shown in Figure-12).
[0040] As shown in Figure-1and Figure-3, Spool (9) can be manually moved from the outward situation to the inward situation by knob (15), which is connected with spool (9) through a tie-rod (34), passing across the insert-bush (3) and hollow bush (4). Spool (9) can also be moved likewise by merely pushing it manually from its projection (33), as shown in Figure-5 and Figure-6. Spool (9) can also be moved likewise by pushing it by a rotary cam (46) , as shown in Figure-15; or by applying fluid pressure at inlet (47), as shown in Figure-16. In other words, the spool can be mechanically moved from outward situation to inward situation in several different manners.
[0041] The spool-spring (8), which is essentially a helical compression spring, firmly resting on the inside of hollow bush (4) exerts force on spool (9) when it is at inward situation. One or more plunger-springs (7) exert force on plunger (5) when plunger is in pulled position (21). The solenoid coil (14), when supplied with requisite electrical energy develops enough electromotive force to cause plunger (5) to travel from un-pulled position (21), to pulled position (22), in few milliseconds consistently.
[0042] Functioning of our inventive mechanically de-latchable Solenoid Valve (10) with electrical pulse operated solenoid coil (14) is as follows:
[0043] As shown in Figure-12 and Figure-1, in de-energized and de-latched state, inlet port (26) and outlet port (27) of 3-port valve (35) are disconnected (also called “valve is close”), outlet port (27) and optional exhaust port (28) are connected, and
a. The spool (9) is in inward situation , spool-spring (8) is in compressed mode
b. Plunger (5) is in un-pulled position (21), plunger-springs (7) are in uncompressed mode
c. Spherical ball (20) is substantially in the recess (17).
[0044] To open the 3-port valve (35), that is, to connect the inlet port (26) and the outlet port (27) of the 3-port valve (35), the pulse operated solenoid coil (14) is given electrical energy at rated voltage and volt-ampere for less than 200 millisecond. Magneto-motive force generated due to magnetic field created thus, and which is known, pulls the plunger (5) to pulled position (22), and in the meanwhile compresses the plunger-springs (7).
[0045] While trapped in the recess (17), the spherical balls (20) were constantly pushed away by wedge face of spool (9) due to Force FSS from spool-spring (8) acting on spool (9). Figure-2 and Figure-13.
[0046] As Figure-3 shows, un-trapping of spherical balls (20) allows spherical balls (20) to move away from spool (9) to another position, where edge (36) of wedge (6) touches spherical ball (20) just above diametric width (37). This position is called second position (42) (Figure-4), of spherical ball (20) and is consequent to force Fss x Sin? (39) acting on spherical ball (20) due to tapered edge (30) of the spool (9). The spool (9), in turn, owing to force Fss of spool-spring (8), takes outward situation; causing inlet port (26) and outlet port (27) to get connected, in other words, the 3-port valve (35) is open. The spherical ball (20) is, in turn, locked in second position (42) due to flat face (29) of spool (9). In this second position (42), the spherical ball (30) obstructs the plunger (5) from returning back to un-pulled position (21). The plunger (5) therefore, stay puts in pulled position (22), as if the solenoid coil (14) is in “energized state” even while the electric energy is disconnected after pre-determined short time. At the same time, plunger (5) continues to apply force FPS x Sina (38) on spherical ball due to force FPS of plunger-springs (7) acting on Plunger (5). Figure-14.
[0047] At this stage the plunger (5) is in pulled position (22) exactly matching “energized” state, and which is thus the latched state, although no electrical energy is required by solenoid coil (14) to remain latched, making our invention an energy efficient solenoid valve.
[0048] To disconnect the inlet port (26) and the outlet port (27), in other words to close the 3-port valve (35), the spool (9) is mechanically assisted, against the force Fss of spool-spring (8), to move from outward situation to inward situation. Such movement of the spool (9) causes displacement of the flat face (29) of the spool (9) away from in-front of the spherical ball (20) and the spherical ball (20) is unlocked from second position (42). Force FPS x Sina acting on the spherical ball (20) by edge (36) of wedge (6) of plunger (5) due to plunger-springs (7), pushes the spherical ball (20) back to first position (41) (Figure-2, 14). Plunger (5) is thus free to travel back to un-pulled position, corresponding to de-energized state and de-latched state, due to force FPS of plunger-spring (7).
[0049] In the first embodiment, the spool (9) is manually assisted through the knob (15), such that spool (9) moves from outward situation to inward situation by pulling the knob (15) which is connected with spool through a tie-rod (34) passing across the insert-bush (3) and hollow bush (4). Figure-1 and Figure-3.
[0050] In the second embodiment, the spool (9) is manually assisted through the projection (33) such that spool (9) moves from outward situation to inward situation by pushing the projection (33). Figure-5 and Figure-6.
[0051] The projection (33) can be pushed manually by the press of a finger. The projection (33) can alternatively be pushed by using an auto-returning rotary cam (46); auto-returning obtainable by a known torsion spring (not shown), so that rotary cam does not hinder travel of spool (9) from inward situation to outward situation during energizing in next operation. Figure-15 illustrates this embodiment by two views of auto-returning rotary cam (46).
[0052] The projection (33) can also be pushed by applying a fluid pressure through inlet (47) as shown in Figure-16. In such an embodiment, seal (18-1) ensures that the fluid pressure does not intervene with operating pressure of the valve (35).
[0053] The spool, thus, can be moved from outward situation to inward situation by any other mechanical means/manner, not limited to embodiments described here.
[0054] The solenoid valve (10), once de-latched by mechanically pulling the spool (9) from solenoid end (32) (as shown in Figure-1,3), or by pushing the spool (9) from valve end (31) (as shown in Figure 5,6, 15,16) , and restoring the spherical ball (20) in trapped state of the first position (41) ; is again ready to be energized and the above cycle of closing and opening of associated 3-port valve (35) is repeatable.
[0055] In the embodiments above, the drawings and description is to essentially describe the invention of interdependent locking of plunger (5)and spool (9) to achieve latching and mechanical de-latching of solenoid valve (10), described here by use of spherical ball (20) and corresponding construction of recess (17) of hollow bush (4), wedge (6) of plunger (5) and faces (29,30) of spool (9); and therefore the invention should not be construed to be limited to any aspect of description given hereinabove so far as such interdependence is achieved.
[0056] The embodiment described above is around a 3-port valve (35), however, the invention has no such limitation and the arrangement is workable equally effectively with valves having more or less numbers of ports.
[0057] The word “trapped” and “locked” are used interchangeably.