US2236227A - Valve - Google Patents

Description

March 25, 1941 I' c. wANTz,

VALVE Fiied Aug. 15, 1938 3 Sheets-Sheet 1 c. WAN-rz'r March 25, 1941.

VALVE Filed Aug. 15, les

3 Sheets-Sheet 2 ciu/ 3 Sheets-Shree?l 3 C. WANTZ March 25, 1941.

Patented Mar. 25, 1941 VALVE y Clarence Wantz, Milwaukee, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee,

Wis., a corporation of Wisconsin f Application Aug-ust 15, 1938, Serial No. 225,018

3 Claims.

'I'his invention relates to gas valves and refers particularly to automatic shut-oi valves for stopping the supply of gas to a burner orthe like in the event of failure of its pilot light.

While diiierent types of shut-oir valves for this purpose have been provided in the past, it has Vbeen found expedient to control the same by means., of a thermocouple having its junction located 'i'n juxtaposition to the pilot ame so that the heat of the ame inducesv a current flow which is used to hold the valve open. With this arrangement, extinction of the pilot name is accompanied by Resetting of closure of the lshut-oit` valve.

these valves is done manually,

and inasmuch as it requires a short time for the thermocouple tobecome effective, it is desirable to positively Aprevent. the

burner during flow of fuel'to' the the interim, and this invention therefore has as its primary object to provide means operable concomitantly with the resetting of the valve for positively closing off the Viiow of fuel to the burner.

Another object of this invention is to provide a simple unitary valve structure for Athe purpose stated, wherein the movable valve element which is biased to closed position is held open by a.

latching device maintained operative by an electromagnet deriving its electrical energy from the thermocouple.

Inasmuch as it is desirable to have the valve valve with the magnet in such a manner that great mechanical advantage is gained.

With the above and other objects in view which will appear as the description proceeds, this in.-

vention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be madeas come within the scope of the c1aims.-

.The accompanying drawings illustrate several complete examples of the physical embodiment of thel invention constructed in accordance with the best modes so far devised for the practical application of which:

the principles thereof, and invertical sectional view 'through a conducted thereto.

Y housing, as shown.

(Cl. 15S-117.1)

Figure 5 is a. vertical sectional view through 10 Y another modied embodiment of the invention.

Referring now particularly to the accompanyingI drawings in which like numerals indicate like parts, the numeral 5 designates a valve casing having an inlet 6 and an outlet l. The inlet l5 6 is connectible with a source of gas supply, and the outlet is connected to a burner 8, or any other device to be supplied with fuel.

A pilot burner 9 mounted in juxtaposition to the burner provides for the ignition of the gas 20 A partition III in the valve casing is Vinterposed between its inlet and outlet and has a valve port Il'adapted to be closed by a valve disc l2. The valve disc is carried b'y a sternl I3 slidably mounted in the cover I4 which 25 closes the vtop of the casing. A compression spring I5 bearing against the valve disc yieldingly urges the same to its closed position seated on the periphery of the port II.

v The cover I4 is provided with a chamber I6 in 30 which a latch, designated generallyV by the numeral I1, and an electromagnet I8 are disposed. The latch I'I consists of a lever I9 pivoted as at 20 and having a latching finger 2I adapted to hook over a shoulder 22 formed in the stem I3. 35 The opposite outer end of the lever I9 carries an armature 23 engageable with poles 24 of the electromagnet.

The coil 25 of the electromagnet has one end grounded 'to the casing and its other end con- 40 nected by a lead 26 with a center terminal 21 passing through the wall of the chamber I6 but electrically insulated therefrom. A thermocouple 28 having its junction 29 positioned adjacent to the pilot light 9 has one of its leads 45 electrically connected with the center terminal 21. and its other lead formed by its outer tubular shell electrically connected with the body of the Hence, Yelectromotive force generated by the thermocouple in response to a temperature rise at its-junction 29 eiects energization of the A electromagnet, which together with a spring 30 actingfon the latch, holds the latch in an operative position engaging the shoulder 22 and hold- 55 on the stem I3 thanl does spring- 30, but a' lesser force than spring 30 plus the magnetic pull on the armature 23.

Upon extinction of the pilot flame, the cessa` tion of current flow in the electromagnet results in deenergization of the magnet. The pull on the armature thus drops to zero; and as the spring I5 is stronger than spring 30, the stem I3 with the valve I2 moves towards closed position rotating the latch lever on its pivot 20 until the latch finger 2| becomes disengaged from the shoulder 22. As soon as disengagement is complete, the force of the spring 30 is no longer transmitted to the stem I3 axially, but only transversely. The slight frictional restraint thus imposed upon the stem I3, however, does not interfere withv the secure closure of the valve by the spring I5.

Thus, spring I5 can be made as strong as desired to obtain adequate seat pressure as long as spring 30 is weaker than spring I5 and spring 30 plus pull of armature 23 when magnet I8 is energized is more than spring I5.

To reopen the valve and reset the latch, a manually operable plunger 32 projects up through the bottom of the valve casing. This plunge:` is yieldingly urged to its lower extended position by a coil spring 33, an-d upon being pushed up lifts the valve disc I2 oil its seat, as indicated in dotted lines in Figure 1. Concomitantly with the lifting vof the Avalve disc in this manner, the port II' is closed by a valve disc 34 carried by the plunger. Hence, as long as the valve disc I2 is held up manually and for the period of time required for the thermocouple to become active, the flow of gas to the burner 8 is positively prevented.

Ordinarily, this construction aiords adequate protection; but if positive assurance against the possibility of holding the valve open manually is required, the plunger may be constructed as illustrated in the modified embodiment shown in Figure 3. With this construction, the valve disc 34 is slidably mounted on the stem 35 of the plunger 32 and is yieldingly urged outwardly thereon by a coil spring 36. Thus, in resetting the valve, the initial movement of the plunger 32 engages the valve disc 34 with its seat prior to contact of the plunger stem 35 with the valve disc I2, and only by continued upward movement is it possible to unseat the valve disc I2 and raise the same to its open position.

It is, of course, desirable to have the valve seat firmly; and to this end, the spring I5 is qute strong, but the electromagnet energized by the E. M. F. of the thermocouple is weak. Hence, it is necessary that the latch mechanism have considerable mechanical advantage.

The construction shown in Figures 1 to 4, inclusive, attains this object; but in the modication illustrated in Figure 5, even greater mechanical advantage is achieved. In this construction, the valve member I2 is mounted in the same manner as hereinbefore described and is urged to its closed position by a heavy spring I5. Thel manner of resetting the valve is substantially the same as that employed in the modined embodiment illustrated in Figures 3 and 4.

The latch structure, however, is of improved design and comprises a substantially hook-shaped ing the valve open. The spring 30 is a flat leaflever 40 pivoted on a fulcrum 4I and having a hook 42 to engage under the shoulder 22. The outer extended arm 43 of the lever carries the armature 23 of the electromagnet, and a light coil spring 44 presses down on the lever 43 to trip the latch when the electromotive force in the magnet depreciates to a predetermined value.

The shoulder 22 is at right angles to the axis of stem I3 and the fulcrum 4I and the shoulder 22 are in a line which is parallel to the axisofl stem I3 so that the force of the spring I5 does not impart a turning moment to the latch lever, and consequently, the movable valve member can be held open against the tension of a comparatively heavy spring by the light force of the electromagnet.

As stated, the light spring 44 trips the latch when the electromotive force in the magnet depreciates to a predetermined value, and thus urges the lever arm away from the magnet. Hence, in resetting the valve, the lever arm must be lifted and to this end, a head 45 on the stem I3 is engageable with a lug 46 depending from the arm 43. The head 45 is slotted'to accommodate the hooked end 42 of the latch lever.

From the foregoing description taken in connection with the accompanying drawings, it

be readily apparent to those skilled in the art that. this invention provides a simple automatic shut-off valve combination by which the ow of fuel to a burner is positively shut off during the resetting of the valve, and whereby absolute guaranty against defeating the safety feature of .the valve is assured.

What I claim as 'my invention is:

1. In an automatic shut-off valve having a reciprocable valve element biased to closed position with a substantial force and having a surface substantially transverse to the line of motion of the valve element: a latch member having a part-engageable with said surface to hold the valve element open against its biasing force;

means mounting the latch member to swing about a point lying substantially within' a circle normal to and having its center on the axis of the valve element, the radius of said circle being equal to the maximum radial distance that the point of engagement between the latch member part and the` surface it engages is from the axis of the valve element so that the biasing force acting on the valve element when held in open position by the latch member is incapable of imparting a latch disengaging turning force to the latch member; a spring acting on the latch member with a force capable of disengaging the same but considerably lighter than the biasing force acting on the valve element; and means for releasably holding the latch element against unlatchlng motion induced by said spring.

2. An automatic shut-oir valve of the character described comprising: a valve body having an inlet and an outlet; a port in the valvebody affording communication between the inlet and outlet thereof a valve member mounted for reciprocating movement to and from a position closing the port; a substantially heavy spring yieldingly urging the valve member to its closed position; means on the valve member having a surface substantially transverse to the line of motion of the valve member; a pivoted latch having a pm movable therewith te and from engagement with said surface to hold the valve member in an open position; means mounting the latch for swinging motion about a fulcrum point substantially encompassed by a circle normal to and having its center" on the axis of the L, valve member, the radius of said circle being equal to the maximum radial distance that the point of engagement between the latch memberV part and the surface it engages is from the axis of the valve member so that the valve spring is incapable of imparting a latch disengaging turning force to the latch member; an armature carried by the latch member at a distance from its fulcrum; an electromagnet arranged to act on the armature and hold the latch member in its operative latching position; means depending upon the maintenance of a predetermined condition for energizing the electromagnet; a spring acting.

on the latch member with a substantially light force to effect disengaging motion of the latch member upon deenergization of the electromagnet; a manually operable member for moving the valve member -to-its open position and to eect setting of the latch; and a valve member movably associated with said manuallyoperable member-to close the lportin advance of engagement of the manually operable member with'the first named movable valve member so that the port is positively closed during the setting of the latch.

3. An automatic shut-off valve of the character described comprising: a reciprccable valve element having means thereon prvidinga surface transverse to the line of motion of the valve .ele-

ment; a substantially heavy spring' yieldingly urging the valve element in one direction to a closed position; a latch ,member having a part engageable with said surface to hold.'the valve element in open position; means pivotally mounting the latch member for swinging motion to and from its operative latching position about a point substantially encompassed by a circle normal to and having its center on the axis of the valve element, the radius voi! said circle being equal to the maximum radial distance that the point of engagement between the latch member part and the surface it engages is from the axis of the valve element so that thelvalve spring while acting on the latch member when the -same engaged with said surface of the valve element is incapable of imparting .a latch disengaging turning force to the latch memberuwhereby the latch member is capable ofi holdingv the valvey light spring during energizationl

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