US2312479A - Control system - Google Patents

Description

March 2, 1943. W.. A. RAY

v CONTROL -sYsTEM Filed March 28, 1941 MLU/JMA @4);

/HL/f/v T02.

Arma/viv Patented Mar.`2, 1943 AUNITED STATES PATENT OFFICE coN'raoL- srs'rEM William A. Ray, Glendale, Calif. Appucauon Mann aaien, serial No. 'assale (Cl. 23e-'21) 3 Claims.

for rendering the system safely inoperative upon the failure of means 'normally controlling the value of the condition. I

Another object is the provision, in ar iluid control system, of a safety valve 'connected in series with an automatically operated valve normally controlling `the flow of uid, the safety valve being maintained in open position only while the value of a condition resulting from the flow of fluid remains within normal limits.

Another object is the provision, in a heating system employing :duid fuel, of means of the character described in the preceding objzect whereby fu'el ilow is obstructed upon abnormal rise of temperature; additional means being provided whereby upon extinction of the pilot burner flame the fuel ow is also obstructed.

Another object is the provision of a combination control device, which comprises a condition responsive device with which is associated independent control means actuated in response to abnormal change in the same condition.

Other objects andadvantagesgof my invention will be found in the description, the drawing,

A and the appended claims.

For complete understanding of the invention.

reference may be had to the following detailed.

description and accompanying drawing wherein:

Figure 1 is a mainly diagrammatic view of heating control apparatus embodying my present invention; and

Figure 2 is a transverse section taken generally along the line 2-2 of Fig. 1.

In the drawing, the numeral Il indicates a main burner which is connected by a conduit I2 to the outlet I3 of a fluid pressure operated valve generally indicated at I4. Connected in series with and ahead of valve I4 is another valve I5 of the rotary plug type, tol the inlet of which is connected an electromagnetically controlled safe'- ty valve generally indicated at I6.

The valve I4 comprises a casing I1 having an opening in its top wall which is'closed by a iiexible diaphragm I8. Securing the diaphragm to the casing and providing a pressure chamber thereabove is a housing I9. Extending from a pressure plate 20, secured to the underside of the diaphragm, is a stem 2| which is pivoted at its lower end on an intermediate portion of an arm 22. This arm is pivotally mounted atene of its ends on a pin 23 secured to the casing. Pivotally connected to another intermediate portion of arm 22 is a stern 24 for a closure member 25. which closure member is cooperable with a valve seat 26 provided in the bottom wall ofthe casing.

A compression spring 2l, connected to the other end of arm 22 and to a side wall of the casing,

is so arranged as to eifect snap-action of the closure member in its opening and closing movements 'as arm 22 moves past center. So that this snap-action may be fully effective, the upper and lower portions of stem 2I are interconnected by a lost-motion device 40. Urging the diaphragm and the closure member upward, is a compression spring 23.

The safety valve I6 comprises acasing 2,9 having a ported partition 30 providing a valve seat 3l. Cooperable with this seat is a closure member 32 mounted on a rod 33, the free end of which sealingly extends through a side wall of the casing and is provided at its outer end with a compression spring 34 which urges the closure member 32 toward its seat. Mounted in the safety valve casing 29 is an electromagnet 35 comprising a U-shaped core 38 which carries on one of its arms an energizing coil 31.

Mounted on the stem 38 of the plug valve is a cam 39 which, in the rotation of the plug valve, is adapted to engage the outer end of rod 33 and thereby move the closure member 32 away from its seat and into engagement with the pole faces of the electromagnet core 36. The closure'member 32 is constructed wholly or in part of magnetic material so that when it is brought into engagement with the core, while the same is energized by passage of current through coil 3l, the closure member will be magnetically retained in open position against the bias of spring 34.

The electromagnet 35 is so designed that the closure member 32 is magnetically held only when it is rst brought into engagement with the core, no attraction of the closure member through space being contemplated. ItI Will be noted that the cam 39 is so arranged with respect to the plug valve that the same is closed when the safety Valve closure member is `moved thereby to its open position. The general combination of plug valve and safety valve shown herein is described and claimed in my copending application Serial No. 319,735 filed February 19, 1940.

Mounted in a wall 45 of a boiler 48, which is heated by the main burner II, is a combination thermostatic control device generally indicated 2. v at 1L-and cemprsiag a thermal buib'n which is sealingly mounted in the boiler by means of a 1 boiler wall.

fitting 4 9, threaded in aflange .50 welded to the outer end of the iltting'and surrounding the bulb,

" Vis provided for the compression of packing material 52 which serves to sealingly hold the bulb in position.` The outer end of the thermal bulb is iluidlyconnected by a pipe 53 to the valve housins 1,9, A

'I'he thermal bulb is of conventional type and contains a-volatile -fluid which, upon a predetermined rise of temperature of the boiler water,

expands and thus ,produces a pressure Within housing `I9 aboveA the diaphragm which is effective to move the same downward against the bias of spring 28 so that closure member 25 is brought into engagement with its seat.

. Mounted on an outer portion of fitting 43 and in good thermal connection therewith is a curved bimetallic strip 54, lto the free endv of which is insulatingly secured a metal strip 55 which carries an adjustable contact screw 55 cooperable with a relativelyfixed contact element 5l insulatingly mounted on another portion of the fitting 49' and 'normallyinengagement therewith. Surrounding-the bimetallic member is a cap 53, secured -to the 4fltting`49 and insulatingly Supportingterminals 59. to which the contact elementsv 56 and 5l are `connected by wires 50 and 6 l respectively.

For the energization of the electromagnet 35,

position' by the bimetallic member at normal operating temperatures ofthe "boiler, With the parts in the ppsitionsshown in thc drawing, .fuelsup'ply to both the main burner I I and the pilot burner 6451s obstructed by the safety a valve closure vmember 32. I tion ofthe system, the plug valve I5 is rotated Y from its open position, as shown, to a closed poi' sition wherein engagement of cam 38 with the end of rod 33 moves closure member 32 away from its seat and into engagement with the pole To initiate opera-'- faces of core 35', whereupon fuel can flow through a pipe 58, connected to the outlet of the safety valve, tothe pilotburner 64 where it is lighted. The plug valve is manually retained in safety-valvelopening position until the thermoelectric device ,52` hasbecome sufficiently heated vby the pilot burnerflame togenerate current in an amountfsufllcientA to cause the electromagnet to hold the vvarmature-closure member 32 in the position shown by the broken-lines. When this occurs, the plug valve-may be returned to its open position, fuel then' flowing to the automatic valve I4 which, if Vthe water in the boiler is cold, wil1 be in open' position on account of the-con- Itraction f the fluid in the thermalbulb 43. i Fuel can therefore now flow to the main burner Il where it i's'ignited bythe pilot burner name. When the temperature of the boiler water reaches` a predetermined degree, the pressure of the 'fluid in thelthermal bulb, applied to the-dia phragm Il, effects closure of the automatic valve.

A hollow nut l, threaded in the" deenergizing electromagnet 35. The

Upon resultant cooling of' the water, due to reduced fluid ,pressure above the diaphragm the valve yreopens runder the force of spring 28;' recycling of the automatic valve maintaining thel water temperaturebetween predeterminedlimits.

If, due to faulty operation. of the automatic valve or its control means, or from other causes, the temperature of the water rises to an abnormal degree, the bimetallic arm 54 warps outwardly, opening contacts 55 and 51 and thereby safety valve closure member 32 is thus permlttedto return to its seat under the force of spring 34.

Fuel flow to both the main and the pilot burner f is therefore obstructed' and the system must be manually reset" as described above to reinitiate operation after the cause of the failure has been corrected. lAs has beenpointedvout, the bimetallic member is in intimate thermal `contact with thetting 43 (which fitting is preferably .of metal having high heat conductivity, such as brass) and is .insulated-from the surrounding atmosphere by the cap 53. The bimetallic member is therefore approximately at the temperature of the boiler water. angular arrangement of contact .51, a wiping action occurs in the relative movement of the contacts.`

An additional safety feature is provided b y the pilot-burner-heated thermoelectric device. If the pilot burner should be accidentally extinguished, upon cooling of the thermoelectric device the resultant cessation of current generation deenergizes the electromagnet and the safety valve closes.

While I have herein shown anddescribed my inventi'on in connection with a water heating system,`it is obviously also adapted to the control-of other 'condition changing systems, such as room heating, refrigeration, fluid pressure andV the'like, wherein additional safety means are desirable which becomes eil'ective upon the failure of the automatic control means, means responsive to the various conditions being substituted for the thermostats shown. I therefore wish it to be understood that the system herein shown and described. isv merely by way of illustrationand that I intend therefore to be limited only lbythe scope'v of the appended claims. The term space as vemployed inthe claimsis intended to de'ne any condition of 4 4 first valve for supplying fluid fuel to said burner,

`thermostatic means responsive to the temperature voiY said medium for controlling said ilrst valve so that the temperature of the medium is normally maintained `between predetermined limits, said thermostatic means including a thermal bulb immersed in said medium, a safety valve connected-1 in series with said first valve and biased to closed i position,l manually operable means for opening said safety valve. .means for normally retaining said lsafety valve in open position against the force of said bias, and thermolstatic meansmounted on saidl thermal bulb for Y .rendering saidV safety valve retaining means ineffective upon abnormal rise of temperature a d-. jacent-the bulb.

2. In a heating control system for a space.: a

ture yoi? said medium for controlling said iirst valve so thatthe temperature of the medium is normally maintained between predetermined limits,said thermostatic means includinga thermal bulb immersed in said medium, a -safety valve connected in series with said rst valve and biased to closed position, manually operable means 1 for opening said saiety valve, electromagnetic VV means eiective whenenergized to retain said safety .valverin open position against the force of said bias when it ls irst brought to that posito said burner, thermostatic meansresponsivev to v the temperature of said medlum;i'or automatif cally operating'said valve so that the temperature of the medium is normally maintained-between "predetermined limits, said thermostati'c means including a thermal bulb cimmersed in s'aid mediuxn, a safety valve connected in series with said pressure'operated valve and biased to closed po-' sition, manually operable means for opening said l safetyflvalve, electromagnetic means leiective `when energized to retainsald safety -valve"l in tion by said manual'- meanaandl thermostatic said safety .valve is closed burner is obstructed. i b

3. In 'a heating control system' for a space: a ,burner for heating the medium'in said space, a

'open position against the force of said bias when it' is rst brought to thatl position bylf'said fmanual means; and 'thermostatic switching; means mounted on said thermal bulb, .said switching means being effective upon abnormal rise oi'tem-V perature adjacent said bulb to deenergize said electromagnetic means so that said safety valve is-closed and fuel supply'to the burner isobv 20 structed. pressure operated valve for supplying fluid fuel WILLIAM A. RAY.

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