US2887546A - High pressure, explosion proof, fluid flow controlled electrical switch - Google Patents

Description

May 19, 1959 R. HATFIELD ETAL 2,

HIGH PRESSURE, EXPLOSION PROOF. FLUID FLOW CONTROLLED ELECTRICAL; SWITCH Filed June 26. 1957 i I I III RobenMaffiz/o Asa Tam E) R. L. HATFIELD ET AL 2,887,546 HIGH PRESSURE, EXPLOSION PROOF, FLUID May 19, 1959 FLOW CONTROLLED ELECTRICAL SWITCH Filed. June 26, 195'? 2 Sheets-Sheet 2 INVENTORS a m W y United States Patent HIGH PRESSURE, EXPLOSION PROOF, FLUID FLOW CONTROLLED ELECTRICAL SWITCH Robert L. Hatfield, Kansas City, Kans, and Raymond C. Webster, Van Nuys, Calif., assignors to W. E. Anderson, Inc., Kansas City, M0., a corporation of Missourr Application June 26, 1957, Serial No. 668,207

3 Claims. (Cl. 200-81.9)

This invention relates to the field of electrical switching apparatus and, more particularly, to electrical switching mechanisms of a type adapted for employment in applications where the switch must be responsive to flow of fluid or similar parameters of a fluid system.

It is an important object of the apparatus to provide such switching apparatus which is adapted for use in connection with high pressure fluid systems and in surroundings where the overall apparatus must be rendered explosion proof by isolation of the electrical parts from communication with the fluid system to Whose parameter the switch is to be responsive.

Another important object of the invention is to provide such switching apparatus in which the necessity of using conventional isolating means, such as diaphragms, bellows, packing glands, or the like, is avoided.

Another important object of the invention is to provide such switching apparatus in which magnetically cooperable parts, which may be isolated in a fluid sense from each other by means of rigid structure without affecting their magnetic operability, are employed.

In order to illustrate the principles of the invention and their wide applicability in presenting switching apparatuses adapted to be responsive to certain parameters of a fluid system and to admit of various constructions, two embodiments showing currently preferred constructions will be described. One of such embodiments is adapted for direct mounting upon a pipe forming a part of a fluid system and responding to fluid flow through such pipe, while the other illustrative embodiment is adapted for connection with a fluid system by means of connectinglines for carrying to the apparatus the differential pressures to which the apparatus is adapted to respond.

Accordingly, it will be understood that there are a number of other specific objects of the invention, including certain significant details of construction, which will be 'made clear or become apparent as the following description of the illustrative, preferred embodiments of the invention progresses.

In the accompanying drawings:

Figure '1 is a cross sectional view of a fragment of a fluid system pipe showing one embodiment of switching apparatus installed directly thereupon, the view being along a central, longitudinal section of the apparatus;

Fig. 2 is a fragmentary elevational view taken on line Il-II of Fig. 1;

Fig. 3 is a cross sectional view takenon line III-III of Fig. 1;

Fig. 4 is a fragmentary elevational view taken on line IV-IV of Fig. 1;

Fig. 5 is a side elevational view of another embodiment of switching apparatus contemplated by the invention;

Fig. 6 is a top plan view of the embodiment shown in Fig. 5;

Fig. 7 is :a central cross sectional view taken on line VI'IVII of Fig. 6; and

Fig. 8 is a fragmentary cross sectional view taken on lineVIII-VIII of Fig. 6.

2,887,546 Patented May 19, 1959 Referring first to the embodiment illustrated in Figs. 1-4 inclusive, the improved, explosion proof, flow responsive, switching apparatus is generally designated by the numeral 10, while a pipe forming a part of the fluid system is generally designated by the numeral 12, and, as illustrated, is preferably horizontal at the zone thereof at which the switching apparatus 10 is associated therewith. The pipe 12 is threadably tapped as at 14 from its top side to receive the threads 16 of a lower, outer housing section 18 of the switching apparatus 10. A sufficient number of threads 16 are provided to engage with the threaded hole 14 to effect a fluid tight and explosion proof coupling between the pipe 12 and section 18.

The lower housing section 18 is provided with an elongated, generally cylindrical, substantially vertical bore 20 which is enlarged adjacent its upper end as at 22 to present an upwardly facing shoulder 24, the enlarged portion 22 of bore 20 also being provided with an annular groove 26 spaced above the shoulder 24. A generally cylindrical, hollow, inner casing 28 provided with an uppermost, outturned, annular flange portion 30 is received within the bore 20 of the lower section 18 with a lowermost part of the inner casing 28 extending below the outer housing section 18 and into the interior of the pipe 12. Inner casing 28 is held within the outer housing section 18 by means of a split retainer ring 32 engaging the top of flange portion 30 and received within the groove 26, a fluid tight seal being effected by means of a sealing O-ring 34 disposed and compressed between the lower extremity of flange portion 30 of casing 28 and the shoulder 24 of housing section 18 when the casing 28 is forced downwardly for emplacement of the retainer ring 32.

The inner casing 28 is closed at its lower extremity by a bottom wall 36 from which depend a pair of spaced cars 38 and 40 (see Fig. 2). Pivotally mounted by means of a pin 42 extending between the ears 38 and 40 is a device generally designated 44 and including a block 46 between the ears 38 and 40 and receiving the pin 42, fluid flow responsive structure in the nature of a paddle 48 secured to the block 46 as by a screw 50 and depending below the block 46 for imposition thereagainst of fluid flowing in the pipe 12, and an upstanding metallic element 52 suitably secured to the block 42 and normally extending up alongside a lower portion of the inner casing 28 which is preferably-exteriorly flattened as at 54. The device 46 is so proportioned that the weight of the paddle structure 48 will normally maintain the upstanding metallic element 52 against the flattened surface 54 of casing 28. However, when fluid is flowing within the pipe 12 in the direction indicated by the arrows 56 with suflicient force, the paddle 48 will swing in a clockwise direction as shown in Fig. 1 to move the element 52 away from the surface 54. It may be noted that the structure 48 is preferably L-shaped and includes an upper leg 58 adapted to serve as a stop by engagement with the bottom wall 36 ofcasing 28 when the device 44 nas been swung through an arc suflicient to move the metallic element 52 away from the surface 54 of casing 28 by a predetermined distance.

As will hereinafter become more apparent, it is essential to the principles of the invention that at least a portion of the element 52 as at 60 be of magnetically operable material and that at least a portion 62 of the casing 28 which is adjacently opposite the portion 60 of element 52 must be'formed of nonmagnetic material. In the illustrated embodiment, the portion 60 of element 52, or forthat matter'the entire element 52, will be understood to be formed of iron or the like, while the portion 62 of casing 28, or for that matter the entire casing 28, will be understood to be formed of brass, which-is nonmagnetic. In other suitable constructions, the casing might be of aluminum or plastic materials, for instance.

Within the casing 28 there is an elongated, upright, hollow chamber 64 within which is received an elongated member 66 that is pivoted adjacent its upper end by a pin as at 68. Asillustrated, the member 66 may include a .late'r ally turne d leg 70 to which amagnet 72, of preferablypermanent magnetic characteristics, is secured by means of a bolt 74, nut 76 and underlying washer 78. The member 66 itself is preferably formed of nonmagnetic material and is so proportioned that with the casing 28 disposed substantially vertically, the member 66 will hang V downwardly in a position spacing the magnet 72 from the portion 62 of casing 28 (note that in Fig. 1 the member 66 and magnet 72 are shown in an operative position swung away from the mentioned position which they would normally assume under the influence of gravity alone). An adjustment screw 80 may be mounted upon the member 66 for controlling the spacing of the magnet 7 2 fromthe nonmagnetic portion 62' of casing 28 when the member 66 and magnet72 are in their gravity conditioned position. h 1

The strength of the magnet 72, the spacing of the magnet 72 from the nonmagnetic wall portion 62 of casing 28 under the influence of gravity alone, the thickness of the casing 28 at the zone of the wall portion 62 thereof, and the mass of the magnetic portion 60 of element 52 forming a part of device 44, are so proportioned that, when the element 52 is in its gravity conditioned position against the flattened surface 54 of casing 28, the forces of attraction between the magnet 72 and the magnetic portion 60 of element 52 will exert a pull upon the magnet 72 suflicient to swing the same and the member 66 to the position illustrated in Fig. 1 in which the magnet 72 is against the side of chamber 64 adjacent the nonmagnetic wall 62 of casing 28. They are also so proportioned that, when the device 44 is swung under the influence of fluid flow against the paddle 48 to move the element 52 away from the surface 54, the force of attraction between magnet 72 and magnetic element portion 60 will become insufiicient to maintain the magnet 72 and the member 66 in the swung or operated position illustrated in Fig. l, and the magnet 72 and member 66 will swingclockwise, as shown in Fig. 1, away from the casing wall portion 62 .to a position spacing the magnet 72 from the latter, such action occurring after the forces of gravity acting upon the magnet 72 and member 66 exceed the magnetic forces of attraction between the magnet 72 and the magnetic portion 60 of element 52.

Thus, it will be clear that the member 66 is swung about its pivot 68 to and from an operative position at which it magnetically cooperates with the element '52 depending upon the positioning of the element 52 relative to the casing 28, which in turn is determined by the magnitude of the flow of fluid within the pipe 12 and the forces thereby imposed upon the paddle 48.

Such action of the member 66 is utilized for switching purposes by means of an electrical switching assembly generally designated 82, which may be a switch of the type currently available on the market under the designation Microswitch and which has a reciprocable actuating plunger element 84 and internal contact structure ,(not illustrated in detail, since it forms no part of the inventive concepts of the present invention). The switch -82 is mounted within the chamber 64 as by screws 86 and is provided with a number of terminals 88 in which corresponding wires 90 are attached. A male connecting plug assembly 92 having a number of pins 94 to which the wires 90 are secured in conventional fashion, is mounted at the top of the inner casing 28 by any suitable means such as an insulating plug 96 secured within the chamber 64 by a set screw 98. Obviously, the pins 94 are adapted to receive corresponding parts of a female connector plug (not shown), which in turn is adapted for coupling with connections leading to an external circuit to be controlled by the operation of the switch 82. To complete the explpsionproofandweatherproof insulation. ofthe apparatus 10, it is desirable to provide a cap-like, upper housing section 100 which may be releasably secured to the lower housing section 18 as by bolts 102. The upper housing section 100 is preferably provided with a cavity 104 for accommodating a female plug (not shown), connectible to the pins 94 of plug 92, with a threaded opening 106 communicating with the top of cavity 104 being provided for egress of electrical connecting conduit and the securement of same to the apparatus 10 in explosion proof fashion.

Obviously, the internal contact structure of the switch 82 may be chosen either to open or close the electrical circuit being controlled responsive to inward reciprocation of the plunger element 84 of switch 82. The switch 82 is so positioned within the casing 28 that such plunger element 84 will be shifted by a switch actuating element each time the member 66 swings from its gravity conditioned position to its magnetically operated position. It may also be noted that, if desired, the permanent magnet could be mounted on the element 52 of device 54 with the members 66 including either another permanent magnet 72 or simply a piece of magnetically attractable metal adjacent the nonmagnetic Wall zone 62 of casing 28.

Reference may next be made to the modified embodiment of the invention illustrated in Figs. 5-8 inclusive. In this form of the invention, the switching apparatus is generally designated by the numeral 200. Apparatus 200 includes a cylindrical block 202 provided with an upright cylinder chamber 204 therewithin having a lower portion of enlarged diameter as at 206 presenting a downwardly facing shoulder 208. The bottom of chamber 204 is closed by a plate 210 secured to the block by bolts or the like 212, and by a sealing O-ring 214 received Within an upwardly facing annular groove 216 of the plate 210.

A pair of openings 218 (Fig. 7) and 220 (Fig. 8) communicate with the interior of the cylinder chamber 204 from the exterior of the block 202, the opening 218 entering the chamber 204 adjacent the bottom of the enlarged portion 206 thereof just above the plate 210, While the opening 220 enters the enlarged cylindrical portion 206 adjacent the top thereof and just below the downwardly facing shoulder 208.

A coupling 222 is provided on the block 202 in com municating relationship to the cylinder opening 218 for receiving a conduit 224 adapted for coupling with one fluid pressure source (not shown), and the block 202 is provided with a second coupling 226 communicating with the cylinder opening 220 and receiving a conduit 228 adapted for coupling with a second fluid pressure source. As will later become apparent, the embodiment of apparatus 200 is adapted for response to diflerentials of fluid pressure derived from virtually any types of sources thereof; however, in order to illustrate the utility of the apparatus 200 by reference to a particular application thereof, it may be imderstood that the conduit 224 would be couplable to an upstream port of a fluid carrying pipe (not shown) which is separated from a downstream port thereof coupled with the conduit 228 by means of a baflfie or the like (not shown) within the pipe to create a differential pressure corresponding to the fluid flow within the pipe. I

Mounted for vertical reciprocation within the enlarged portion 206 of cylinder chamber 204 is a piston 230 having an intermediate, outwardly extending, annular flange 232 which slidably engages the walls of cylinder portion 206, the piston being undercut beneath the flange 232 as at 235 to present a space 236 for entry of fluid from the opening 218 into the chamber portion 206 below the flange 232. As will be clear from Fig. 8, fluid from opening 220 enters the cylinder chamber portion 206 above the flange 232 so that the fluidpressures from openings 218 and 220 act oppositely against the flange 232 of piston 230. Obviously, when thepressure of fluid from opening 218 exceeds the pressure of fluid from opening 220, the piston 230 will tend to move upwardly within the chamber 204 and vice versa. A firusto-conical spring 234 is provided within the chamber portion 206 and bears oppositely against the downwardly facing shoulder 208 of block 202 and the upper surface of flange 232 of piston 230. The spring 234 is chosen so that a predetermined differential of pressure between the fluids coupled with the cylinder chamber 204 between openings 218 and 220 will be required before the resistance of spring 234 is overcome and the piston 230 moved upwardly by some predetermined amount within the chamber 204.

Carried atop the piston 230 and secured thereto by fastening means generally designated 236 is a permanent magnet 238. The upper extremity of the chamber 204 is closed by a wall portion 240 of block 202 which is of nonmagnetic material, such as brass, a normal construction being to form the entire block 202 of such nonmagnetic material.

A bracket 242 secured atop the block 202 in any suitable fashion, pivotally carries a device generally designated 244 by means of a pivot pin 246, the embodiment illustrated utilizing a device 244 which is J-shaped and formed to include a leg 248 directly above the nonmagnetic wall portion 240 of block 202. At least such leg 248 or a substantial portion thereof directly above the wall portion 240 must be formed of magnetically attractable material, as illustrated, or of material which is itself magnetized. A second bracket 250 secured atop block 202 supports the upper end of a coil spring 252 which is connected at its lower extremity to the device 244 for normally swinging the device 244 to a position spacing the leg 248 thereof above the wall portion 240 of block 202. Bracket 250 also carries in any suitable fashion, an electrical switch 254, which may be of the Microswitch variety having a depending, reciprocah-le actuating plunger element 256 normally engaging an upwardly facing surface 258 of device 244.

The strength of the permanent magnet 238, the spacing of the latter from the magnetically operable leg member 248, and the mass of the latter are so chosen that when the piston 230 is in its normal or unactuated position, as illustrated in Fig. 7, the device 244 wili remain biased upwardly under the influence of the spring 252 to the position illustrated in Fig. 7 wherein the magnetically operable leg member 248 of device 244 is spaced from the wall portion 240 of block 202. Such parameters are also chosen, however, so that, when the piston 230 is reciprocated upwardly a predetermined distance against the force of spring 234, the magnetic attraction between the magnet 238 and the member 248 will exceed the upwardly biasing force of the spring 252 on the device 244 and the device 244 will be swung downwardly about its pivot 246 until the leg member 248 is engaging the upper surface of block 202 above the wall portion 240 thereof. This swinging of the device 244, of course, reciprocates the plunger element 256 to operate the switch 254. Manifestly, as soon as the exertion of pressure differential of the fluid from opening 218 over that from opening 220 decreases to a point where the spring 234 reciprocates the piston and magnet 238 downwardly a sufficient distance, the upwardly biasing force of the spring 252 will overcome the forces of magnetic attraction between the magnet 238 and the member 248 and the device 244 will swing upwardly to the position illustrated in Fig. 7. It will be clear, therefore, that the pressure differential of the fluids from openings 218 and 220 control the reciprocation of the piston 230 and magnet 238 and thereby the positioning of the device 244 which in turn controls the reciprocation of the switch actuating plunger element 256.

Suitable lead wires 260 connected with the switch 254 pass downwardly through an Lshaped passage 262 in the block 202, suitable packing preferably being provided as at 264. A horizontal stretch 266 of the passage 262 is suitably threaded for receiving in explosion proof fashion a coupling 268 for an electrical conduit 270 which houses the wires 260 as they proceed to a point of connection with an external circuit.

An upper portion of the block 202 is cylindrical and is threaded as at 272 to receive an internally threaded, explosion proof cap 274 that covers and encloses the switch 254, the device 244 and the associated mechanism.

It will now be apparent that the principles and structure contemplated by the invention are ideally adapted for achieving all of the above-mentioned and other worthwhile objects. It will also be understood, however, that a number of modifications or changes could be made from the exact structure shown and described for illustrative purposes without departing from the true spirit and intention of the invention. Accordingly, the invention should be deemed limited only by the scope of the claims that follow.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. Fluid flow controlled, electrical switching apparatus adapted for installation upon a fluid carrying main provided with a hole in a wall thereof, said apparatus comprising: a hollow, sealed housing of which a substantial portion is adapted to extend through the hole of the main and into the latter, at least a part of said portion being of non-magnetic material; means for mounting the housing on the main in closing relationship to the hole with said portion of the housing within the main; an electrical switch mounted within the housing and provided with a shiftable actuating element; means for making electrical connections with the switch and providing coupling thereto from externally of the housing and the main; a member shiftably mounted within the housing for movement to and away from an actuating position whereat the member shifts the element for actuating the switch, the member being yieldably biased away from said actuating position; a permanent magnet mounted on the member and disposed generally adjacent said part of said housing portion; a device of magnetically attractable material shiftably mounted on said housing portion externally of the latter and internally of the main for movement to and away from an operative position disposed proximate said part of the housing portion externally thereof and oppositely to the magnet; structure shiftably mounted on said housing portion externally of the latter and internally of the main and adapted for movement away from a normal position under the influence of flow of fluid within the main; and means operably coupling the structure with the device for shifting of the device toward said operative position thereof as the structure is moved away from said normal position thereof, the structure being yieldably biased toward said normal position thereof.

2. In apparatus as set forth in claim 1, wherein said member, device and structure are mounted for swinging movement about substantially parallel axes.

3. In apparatus as set forth in claim 2, wherein said structure comprises a paddle adapted to extend across a part of the internal, transverse cross-section of the main and to be displaced away from said normal position thereof under the force of flow of fluid thereagainst.

References Cited in the file of this patent UNITED STATES PATENTS 384,570 Grovesteen et al June 12, 1888 2,203,331 Hinsch June 4, 1940 2,204,161 Shepherd June 11, 1940 2,307,304 Rudd Ian. 5, 1943 2,310,504 Aubert Feb. 9, 1943 2,600,309 MacDonald et a1 June 10, 1952 2,773,251 Snyder Dec. 4, 1956 2,869,475 Bobo Jan. 20, 1959 FOREIGN PATENTS 1,055,183 France Oct. 14, 1953

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