GB2107435A - Solenoid valve system with removable waterproof solenoid winding - Google Patents

Abstract

The invention relates to a solenoid valve system for use in a corrosive environment to control the flow of high pressure fluid. The system includes a valve assembly (16) and an electrical cable (27). A waterproof solenoid winding (20) is permanently secured to the end of the cable (27) to form a removable integral electrical component (8), the winding being removably mountable in an operating position around the valve assembly (16). The winding (20) may be quickly and easily removed and replaced in event of electrical failure without disturbing the valve assembly (16). Screws are provided for holding the winding in its operating position. With this arrangement the disconnectible interconnection between the elctric- cable (27) and the remainder of the solenoid valve system is accomplished magnetically rather than electrically, and the solenoid valve system strongly resists failure due to water penetration. <IMAGE>

Description

SPECIFICATION Solenoid valve system with removable waterproof solenoid winding The present invention is in the field of high performance solenoid operated valves for controlling the flow of high pressure air, and more particularly the invention relates to waterproof, high performance solenoid valves which are adapted to be submerged in sea water during operation or exposed to other corrosive environments. The solenoid valve as described is intended to be mounted on a high pressure airgun submerged in water for controlling the firing of the airgun in carrying out seismic exploration operations. The solenoid valve as described can also be used for controlling airguns which are not submerged and for controlling the sudden release of high pressure air or other gases for other purposes.

US Patent No. 3,588,039 high performance solenoid valves capable of withstanding high vibrational forces and of being submerged in salt water, having an all stainless steel magnetic circuit. The solenoid valves shown include a plungerwhich together with a valve stem defines the valve. The plunger is selectively shaped to establish excellent pressure balance for high performance reliability of the magnetic circuit, while the plunger and associated operating parts can be quickly and conveniently disassembled and reassembled without injury to the solenoid valve to remove dirt particles if any particles should inadvertently enter through the supply line.The solenoid winding and its connecting leads are encased in the housing, and its electrical contact pins or prongs are accessible in an electrical male connector for engagement by contacts in an electrical female connector at the end of an electrical cable extending to the solenoid valve.

US Patent No. 4,210,222 describes the actual instant of firing of an airgun being detected by a pressure transducer in fluid communication with a shuttle-operating chamber of the airgun for sensing the sudden surge in pressure occurring therein. This transducer and the contact prongs of the solenoid winding are connected to the electrical cable by inserting an intermediate electrical plug between the contact prongs of the solenoid winding and the female connector at the end of the electrical cable extending to the solenoid valve.

US Patent No. 4,240,518 describes the actual instant of firing of the airgun being detected by a pressure transducer located in the housing of the solenoid valve itself. This transducer is shown grounded to the housing of the solenoid valve, so that it has only one lead connected to a contact prong located near the pair of contact prongs of the solenoid winding and located near a grounding prong forthe solenoid housing. In anotherembodi- ment, this transducer is shown insulated from the housing so that the transducer has two leads connected to a pair of contact prongs near the pair of contact prongs for the solenoid winding. The contact prongs of the solenoid winding and the contact prong (or prongs) for the transducer lead (or leads) are engaged by a female connector at the end of the electrical cable extending to the solenoid valve.

In these prior art solenoid valves there are elas tomeric seals, for example O-ring seals, engaged between the electrical cable connector and the housing of the solenoid valve. The purpose of such elastomeric seal is to prevent the entry or penetra tion of seawater into the vicinity of the electrical contact region between the cable connector and the housing of the solenoid valve. In this contact region the wires in the cable are electrically joined through disengageable contacts with the electrical prongs (contacts) in the valve housing. Such electrical prongs (contacts) lead to the solenoid winding for enabling an electrical signal to be sent from a remote station through wires in the cable to the solenoid winding for actuating the valve, for example for firing an airgun.From the above discussion, it will be understood that there may also be other electrical prongs (contacts) in this contact region which lead to a pressuretransducerfortransmitting an electrical signal through other wires in the cable to the remote station for indicating the actual instant of firing of the airgun on which the solenoid valve may be mounted.

In the situation of an airgun submerged in water and being repeatedly fired for carrying out seismic exploration or surveying, the elastomeric seal associated with the electrical cable connector is subjected to a slight deflection each time that the airgun is fired because of the powerful discharge occurring from the airgun. This repeated slight deflection of the seal occurring at each firing of the airgun tends to cause a water pumping action allowing the water to creep past the seal. Thus, sooner or later the seawater tends to reach the region of the electrical contacts and causes electrical failure due to corrosion problems.

In running a marine seismic exploration, the survey ship may be towing fifty or more airguns in an array. Thus, it will be understood that the likelihood of corrosion problems occurring is increased because of the relatively large number of cable connectors involved. Moreover, the hourly costs of marine seismic exploration are continuing to rise. Therefore, any electrical failure caused by such corrosion of connector contacts is a serious impediment and economic problem for the operator of the survey ship.

It is an object of the peresent invention to overcome these corrosion failure problems by providing a high performance solenoid valve system which is even more reliable electrically than the prior art high performance solenoid valves.

In accordance with the present invention in one of its aspects, the solenoid winding and the electrical cable are formed as an integral waterproof electrical component or unit which can be removed as a unit from the remainder of the solenoid valve. Thus, there are no detachable contacts to become corroded.

Among the advantages of the present invention are those resulting from the fact that the solenoid winding can be removed as a unit and replaced in the solenoid valve without disturbing the valve assembly and without dismounting the solenoid valve from its associated airgun.

In accordance with the present invention in another of its aspects, the pressure transducer for detecting the actual instant of firing of the airgun, often called the "time break" transducer, is formed with its electrical cable as an integral waterproof component.

In accordance with the present invention in a further of its aspects, the solenoid winding, its electrical cable and an end portion of the corrosion resistant housing of the solenoid valve are together formed as an integral waterproof component or unit which can be removed from the remainder of the solenoid valve. Moreover, this end portion of the housing serves as means for removably securing the solenoid winding in its operating position within the solenoid valve.

Another advantage of the foregoing integral waterproof component including solenoid winding, electrical cable and end portion of the housing is that this component serves for removably securing the time-break transducer in its own operating position in the housing of the solenoid valve.

The present invention will be more readily understood from a consideration of the following description in conjunction with the accompanying drawings showing the best mode now contemplated for carrying out this invention in practice. In these drawings, like reference numbers indicate like elements or components throughout the respective views, in which: Figure lisa top plan view of a solenoid valve system embodying the present invention, Figure 2 is a side elevational view of the solenoid valve system. A small portion of an airgun is indicated at the bottom of Figure 2 on which the solenoid valve is mounted, Figure 3 is an elevational sectional view of the solenoid valve system as seen from the same direction as in Figure 2.Figure 3 is a section taken along the plane 3-3 in Figure 1, Figure 4 shows that the solenoid winding, its electrical cable and a removable end of the housing are an integral waterproof electrical component or unit. This advantageous unitary electrical component is shown being removed from the solenoid valve without disturbing the valve assembly and without dismounting the solenoid valve from the air-gun on which is it mounted.

These four Figures show the presently preferred embodiment of the invention. In effect, there is provided an overall solenoid valve system in which the solenoid winding (sometimes called the "solenoid coil") and its electrical cable and an end of the housing are integrated to form a single waterproof component, namely, the electrical component of the solenoid valve. This waterproof electrical compo next can be removed as a unit from the remainder of the solenoid valve which remains as a unit; namely, the operating moving parts of the solenoid valve remain as a unit without being disturbed when the waterproof electrical component is removed and replaced.This novel concept of an overall solenoid valve system will be most quickly understood by looking at Figure 4 which shows the whole system 7 separated into its integral waterproof electrical component 8 and into its mechanical components 9.

The solenoid valve 10 (Figures 2 and 3) is shown mounted on the end portion 12 of an airgun. The manner in which a solenoid valve 10 is used to trigger the firing of an airgun will be understood from the three patents described above in the background, and therefore will not be described here. This solenoid valve 10 includes a main housing or base portion 14 (as seen most clearly in Figure 4) which contains a valve assembly 16. The operating parts of the solenoid valve which move during actuation are in this valve assembly 16, as will be explained later. This solenoid valve 10 also includes a removable top end portion of the housing or cover 18 which integrally contains the solenoid winding 20.The main housing 14 defines an annular channel 22 (Figure 4) encircling the valve assembly 16, and this channel 22 is open and accessible toward the top end of the main housing where the end portion or cover 18 of the housing is located during operation. This cover 18 includes a downwardly extending boss 24 which is hollow to form a thin cylindrical wall 26. The winding 20 and its bobbin (as will be explained later) are potted within this thin cylindrical wall 26 thereby forming an inverted cup of annular configuration which fits snugly within the annular channel 22, as seen in Figure 3.

The electrical cable firing line 27 (Figure 3) for transmitting a signal for energizing the solenoid winding 20 for firing the airgun is directly connected to the leads 28,29 of the winding 20. There are no intervening separatable electrical contacts; in other words, a direct connection is made from the insulating wires 31,32 in the firing line cable 27 to the leads 28 and 29. The solenoid winding or coil 20 is wound about a bobbin 34 (Figure 3) of dielectric material.

The bobbin and winding 34 and 20 are placed within the thin cylindrical wall 26 with the cable wires 31,32 and the adjacent end of the cable located in a passageway 36 drilled in the housing cover 18. There is a nipple 38 welded at 39 onto the cover 18 with the bore 40 of this nipple aligned with the upper end of the passageway 36. The firing line cable 27 extends up through the bore of this nipple 38.

In order to form a waterproof, integral unitary electrical component 8 (Figure 4), the solenoid winding 20, its bobbin 34 and its leads 28,29 together with the wires 31,32 are potted with epoxy potting compound 42 within the cylindrical wall 26 and within the passageway 36. In performing this potting operation, these elements are first subjected to vacuum for withdrawing air so that the epoxy potting material 42 fills all voids. This potting material 42 saturates the convolutions of the winding 20 for preventing the turns of the coil from rubbing against each other and extends down below the lower flange of the bobbin and overlaps the edge of the wall 26 at 44 for providing a secure bond. This epoxy potting material 42 when it sets is relatively rigid.

In order to complete the potting operation, the upper portion of the passageway 36 and the bore 40 of the nipple 38 are filled with polyurethane potting compound 46 which is more flexible than the epoxy material 42. The advantage of using this more flexible potting material 46 is that it accomodates any slight flexing between the cable 27 and nipple 38. It is noted that the nipple bore 40 is roughened, for example by a screw thread configuration, for providing a rough surface area for strong holding and gripping of the polyurethane potting material 46.

In orderto protect the firing line cable 27, there is a tough, stiffly flexible sheath 48 placed around the electrical cable. This protective sheath 48 is a commercially available high pressure hose line containing strong, non-metallic reinforcing fibers.

The end of this protective sheath 48 is anchored by a commercially available mechanically crimped hose coupling 50 to a commercially available fitting 52.

This hose fitting 52 is removably fastened to the nipple 38 by a coupling nut 54.

Thus, it will be understood that the electrical component 8 (Figure 4) is an integral waterproof unit. The solenoid winding 20, together with its bobbin 34 potted into the cylindrical wall 26, form an inverted annular cup fitting snugly into and conveniently removable from the annular channel 22 in the base component 9 of the solenoid valve. The potted bobbin 34 and winding 20, together with the hollow boss 24 (Figure 4) define a socket 60 which fits snugly around the valve assembly 16.

As shown in Figures 1 and 2, the base portion 14 of the housing is fastened to the airgun 12 by a pair of machine screws 56 passing through a pair of flanges 58 on opposite sides of the base 14. The housing cover 18 is removably fastened to the housing base 14 by four long machine screws 62 which extend down into the airgun 12 and screw into the airgun.

Therefore, these four long screws 62 aid the two shorter screws 56 in securing the solenoid valve onto the airgun 12 during operation. However, removal of the four screws 62 enables the electrical component 8 (Figure 4) to be removed as a unit as indicated by the arrow 64, without disturbing the base component 9 nor its valve assembly 16 and without dismounting the base housing 14 from the airgun 12. It is noted that the heads of the machine screws 62 are neatly recessed relative to the top surface of the housing cover 18, as seen in Figure 2.

In order to removably hold a time-break transducer 66 into a socket 68 in the sidewall of the base housing 14, there is a U-shaped slot 70 (Figure 1) in the edge of the cover 18 providing clearance for a tubular fitting 72. The lower end of this tubular fitting 72 has a flange 74 with an O-ring seal 76 which fits down into the enlarged upper end of the socket 68.

There is also an O-ring seal 78 around the lower end of the transducer 66. This transducer may advantageously be of the type described and claimed in US Patent No. 4,286,687 - Augustus H. Fiske, Jr., assigned to the assignee of the present application.

The leads 81,82 of this transducer 66 are directly connected to the wires 83,84 of an electrical time break sensor cable 80 by permanently crimped electrical connectors 85,86. The leads 81,82, wires 83,84 and the permanent connections 85,86 are potted in the bore of the tubular fitting 72 by molded rubber material 87. This rubber material extends out as a tapered sleeve 88 over the end of the cable 70 for resisting flexural stress. The bore of the fitting 72 is roughened, as by a screw thread formation, for providing a strong holding or gripping ofthe material 87. A passageway 89 provides fluid communication with a region in the airgun in which a sudden increase in pressure occurs in firing, as will be understood from US Patent Nos. 8,210,222 and 4,240,518 discussed previously.

Pressurized gaseous fluid, usually compressed air, is supplied to the solenoid valve 10 through a high pressure supply line hose 90 connected to the housing cover 18 through a fitting 92 screwed into a socket 94 in the top of the cover. This solenoid valve 10 is of the dual action type as described and claimed in US Patent No. 4,240,518, namely, it can produce a sudden flow from an inlet port to an outlet port upon sudden energization and it can continuously shut off flow from a supply port to the inlet port by continuous energization. This solenoid valve 10 includes a supply port 96 (Figure 3) communicating with the supply line 90, an inlet port or chamber 98 communicating with the interior of the airgun and an outlet port or trigger port 100, which also is in communication with the interior of the airgun.This latter port 100 is suddenly placed in communication with the inlet port 98 when the valve assembly 16 is actuated by sudden energization of the solenoid winding 20, thereby firing the airgun.

When the solenoid winding 20 is de-energized, pressurized gaseous fluid can flow from the supply port 96 through the solenoid valve assembly 16 to the inlet passage 98 for supplying pressurized fluid to the equipment 12 being cdntrolled by this solenoid valve system. In the event of malfunction of the controlled equipment, this solenoid valve system 7 can be used to shut off the supply of pressurized fluid as explained in US Patent No. 4,240,518. This shut off is obtained by feeding a continuous flow of current through the winding 20. While this continuous current is flowing, the valve assembly 16 is actuated by an additional sudden pulse of current through the winding 20 and thereafter remains held in its actuated condition by the continuous current.

The elements of the valve assembly 16 are essentially identical to the elements shown in the valve mechanism in Figures 4,5 and 7-12 of US Patent No.

4,240,518. These elements of the valve assembly 10 will now briefly be pointed out. If the reader wishes a full description of how these mechanical valve elements function, attention is invited to the specification of that patent. There is a valve stem 102 seated in the upper end of a plunger housing 104 and held there by a retainer 105 held by a retainer ring 106. A slidable plunger 107 encircles the stem 102 and is urged downwardly into engagement with a seal 108 by springs 110 positioned in axially extending cavities in this plunger 107.

When the solenoid winding 20 is de-energized, the plunger 107 engages the seal 106 for blocking communication between the ports 98 and 100, while the supply port 96 communicates with the port 98.

When the solenoid winding 20 is energized, the movable plunger 107 is electromagnetically drawn upwardly against the force of the springs 110, thereby separating from the seal 108 for opening communication between ports 98 and 100. While the plunger 107 is electromagnetically held upwardly, a lip 112 on the upper end of this plunger engages a seal 114for blocking communication between ports 96 and 98. The materials used throughout this solenoid valve system 7 are high-strength, corrosion-resistant materials of high quality. In order to produce a strong magnetic field through the plunger 107, the cover 18, base housing 14, top and bottom portions of the plunger housing 104 and the plunger 107 are made of magnetically permeable, i.e. ferromagnetic, stainless steel.The thin cylindrical wall portion of the plunger housing 104 adjacent to the plunger 107 is made of non-magnetic stainless steel using the construction technique, as shown in US Patent No.3,588,039.

The valve assembly 16 (Figure 4) includes the following elements: plunger housing 104, valve stem 102, retainer 105, ring retainer 106, inlet-tooutlet blocking seal 108, springs 110, supply-to-inlet blocking seal 114, and O-ring seals 115 and 117, seated in circumferential grooves in the valve stem 104. The seal 115 provides a sliding seal against the bore of the plunger 107.

This valve assembly 16 is removable from the lower end of the base housing 14when the base housing has been dismounted from the airgun 12 or other equipment being controlled. There is an internal annular shoulder 118 in the base housing 14 located below the annular channel 22 and projecting inwardly, and there is an external annular flange 119 on the plunger housing 104. This flange 119 abuts up against the internal shoulder 118 for retaining the whole valve assembly 16 in the base housing 14 when the electrical component 8 is withdrawn (arrow) 64 as shown in Figure 4.

There are various other O-ring seals 120 as shown in the drawing for providing sealing against the leakage of high pressure gaseous fluid.

For convenience of description, the "top" and "bottom" of the solenoid valve 10 have been described in relation to the orientation as shown in the drawings. Similarly, for convenience, the terms "top" and "bottom" and similar terms of orientation may appear in certain claims. However, it is to be understood that the solenoid valve described herein can be used and actuated in any orientation relative to the earth's gravitational field, and the claims are to be construed accordingly.

From the foregoing, it will be understood that the solenoid valve system embodying the present invention is well suited to provide the advantages set forth. It is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative.

Claims (11)

1. A solenoid valve system for use in a corrosive environment to control the flow of high pressure fluid including a valve assembly and an electrical cable, wherein a waterproof solenoid winding is permanently secured to the end of said cable forming a removable integral electrical component, said winding being removably mountable in operating position around said valve assembly, said winding being relatively quickly and easily removable and replacable in event of electrical failure without disturbing the valve assembly, and wherein removable fastening means is provided for holding said winding in said operating position, by virtue of which the disconnectible interconnection between the electrical cable and the remainder of the solenoid valve system is capable of being accomplished magnetically rather than electrically and said solenoid valve system strongly resists failure from water penetration.

2. A solenoid valve system as claimed in Claim 1, wherein said valve assembly is mounted in a housing defining an annular channel encircling the valve assembly, said channel being accessible to the outside of said housing, said winding having an annular configuration and being insertable into and removable from said annular channel, said annular winding when inserted into said annular channel being in position for electromagnetically actuating said valve assembly, and said winding and the adjacent end of the cable being potted (encased, embedded) in waterproof dielectric material for forming said winding and the electrical cable as an integral waterproof component.

3. A solenoid valve system as claimed in Claim 2, wherein said means for removably holding said winding in said annular channel include a removable portion of said housing, and said winding and said cable are integrally bonded to said removable portion of said housing by said waterproof dielectric material forming a removable integral waterproof electric component, removable fastening means being provided to fasten said removable electrical component together with the remainder of the housing for holding said winding in said annular channel.

4. A solenoid valve system as claimed in Claim 3, wherein said removable portion of the housing is a cover having an inwardly projecting cylindrical wall, the solenoid winding is potted (encased, embedded) by dielectric material within said cylindrical wall together with a bobbin of dielectric material on which the winding has been wound forming a removable integral waterproof electrical component, and said winding and bobbin potted in said cylindrical wall form an inverted annular cup snugly fitting into said annular channel.

5. A solenoid valve system as claimed in Claim 2, 3 or 4, wherein a transducer is removably inserted into a socket in said housing and said removable portion of the housing serves to hold said transducer in its socket.

6. A solenoid valve system as claimed in Claim 3 or 4, wherein said removable portion of the housing is an end cover engageable with the top end of said housing, said housing has an inwardly projecting shoulder located below said annular channel and said valve assembly has an outwardly projecting flange engaging beneath said shoulder for retaining said valve assembly in said housing when said integral waterproof component is removed from the top end of said housing, and said valve assembly is removable from the bottom end of said housing.

7. A solenoid valve system as claimed in Claim 3, 4 or 6, wherein said removable portion of said housing has a passageway therethrough, said electrical cable is directly connected to said winding through said passageway, and potting material fills said passageway for bonding said winding and said end portion of said cable to said removable housing portion to form said integral waterproof component.

8. A solenoid valve system as claimed in Claim 7, wherein a nipple is welded to said removable housing portion at the outer end of said passageway, and said cable is potted (enclosed, embedded) in dielectric material in said nipple.

9. A solenoid valve system as claimed in Claim 8, wherein the bore of said nipple is roughened for increasing the bond of said potting material.

10. A solenoid valve system as claimed in Claim 2,7,8 or 9, wherein said winding is embedded in relatively rigid dielectric material for preventing movement of the turns of the winding, and the adjacent end of the electrical cable is embedded in dielectric material which is more flexible for accommodating slight flexing of the cable.

11. A solenoid valve system substantially as hereinbefore described with reference to the accompanying drawings.