US1981454A

US1981454A - Stoker control

Info

Publication number: US1981454A
Application number: US568013A
Authority: US
Inventors: Kay Calvin
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-10-10
Filing date: 1931-10-10
Publication date: 1934-11-20
Anticipated expiration: 1951-11-20

Description

Nov. 20, 1934. c. KAY

STOKER CONTROL Filed Oct. 10, 1931 N m M U 5 m v.Jrvoank-m CH4 V/M KA Patented Nov. 20, 1934 UZ-E E E STATES PATENT orr cs Claims.

This invention relates to a stoker control, and more particularly a device for shutting off motive power or giving alarm when certain abnormal conditions exist in the feed hopper of a 5 Stoker conveyor.

The principal object of the invention is to prevent the objectionable condition which results frequently in ordinary stokers when smoke and fumes backpass from the firebowl of the stoker into the feed hopper, and from there into the building where the apparatus may be situated.

Another object is, that the device shall be simple, inexpensive, and not liable to get out of order when in the hands of unskilled users.

In furnace stokers, fine fuel, such as slack coal, is conducted from a feed hopper to the fire, by means of a suitable conveying element, such as a rotatable screw.

Coal usually contains a certain amount of moisture, which causes it to pack in the feed hopper, and even though agitatorsare used, an arching of the fuel is liable to occur in the feed hopper above the screw conveyor. The result is that the fuel in the lower part of the hopper may be entirely exhausted, while from the outside,

the hopper may look as though it contains a sumcient quantity.

When such a condition as the above exists, the open passage through the conveyor and the lower part of the hopper allows smoke and fumes from the furnace to backpass into the building, which is highly annoying and even dangerous.

In my improved device, I provide one or more pivoted arms in proximity to the agitator of a Stoker, the arm or arms being so located that,

as the fuel becomes exhausted in the neighborhood of the agitator, gravity as the actuating force, will cause the arms to drop, thereby operating an electric switch and shutting off the motive power which drives the conveyor. If desired, an alarm may be sounded to give notice to the attendant that the fuel must be replenished.

The features of this invention for which the a protection of Letters Patent of the United States is desired, are collectively grouped in the claims concluding this specification.

In the drawing, which illustrates one embodiment of this invention,

Fig. 1 represents a plan of a stoker feed hopper with my device applied thereto, some parts in the background being omitted;

Fig. 2, a side elevation, portions being broken away to show certain parts in section;

Fig. 3, an end elevation looking from the stoker side, portions being broken away to show parts inside the hopper; and g V I Fig. 4, a diagram, in perspective, showing the parts constituting my improvement, separately from the hopper.

Referring to the drawing, the numeral 10 indicates the feed hopper of an ordinary stoker, to the lower portion of which is attached .a conveyor casing 12 as usual. Within this casing is the usual conveyor worm or screw 14, which also extends through the lower portion of the hopper, as indicated in Fig. 2.

Immediately above the conveyor worm is the usual agitating wheel 15, thisbeing rigidly mounted on a shaft 16 which in turn, is rotatably mounted in bearings 17. The agitating wheel carries a bail or sweep 18, preferably as an integral part thereof, while the sweep may carry one or more horns 19. The conveyor'worm and the agitating wheel are arranged to turn in unison, and are driven from an outside source of power (not shown) in any. usual manner.

What has so far been described, forms no part of my invention, excepting when used in combination with those parts which will now be re- 30 ferred to. i

Oscillatingly mounted backof the agitating wheel 15, are one or more arms 20. Preferably two arms are used, which straddle the agitating wheel, and these armsare so positioned as to be 5 lifted by the sweep of the agitating wheel. The arms may be mounted in any suitable manner so as to rock pivotally, for example, the arms may be rigidly mounted on a, shaft 21, and the latter may be rotatably mounted in the hopper on walls, as indicated at 24. One end of shaft 21 may be extended outside the hopper and carry an arm 25, to which is pivoted a rod 26, and this in turn may be pivoted to the blade 27 of a knife switch 28. This switch has prongs 29 and 30,'between which the blade 27 is operatively mounted. The prongs 29 and 30 form switch terminals, and may be connected in series with an electric motor (not shown) by means of

conductors

31 and 32. The switch terminals may be mounted on a base 34, preferably made of insulating material.

In using the device, the arms 20 are first lifted into a raised position, by hand or otherwise, the raised position being indicated in Figs. 2, 3 and 4. This is done before filling the hopper with fuel, and naturally, as the filling proceeds, fuel is deposited underneath arms 20 and serves to hold these in the. elevated position.

In the elevated position of arms 20, knife switch 28 is closed. Now, as long as substantially the desired minimum quantity of fuel remains underneath arms 20, these will not be allowed to drop into a position very much lower than that shown in Fig. 2. When, however, the fuel supply becomes further exhausted, arms 20, after being contacted by sweep 18 during a part of each revolution of the latter, finally fall to a point where there will no longer be sufficient fuel beneath them,

when released from sweep 18 inthe course of its revolution, to hold blade 27 in engagement with terminal members 30. As soon as blade 2'7 is released from terminal members 30, the motor will be stopped, and no more fuel will be taken away by the conveyor until proper running conditions have again been established.

Thus, the fuel in the hopper will never become exhausted below a certain predetermined level,

' such as indicated by the position 20--1 of arms 20, where they rest on hub l5l of wheel 15. This insures always a sufficient supply of fuel to'act as a plug in the lower part of the hopper, and prevents at all times, the backpassing of smoke or fumes from the furnace (not shown) through the conveyor casing 12.

Obviously, the weight of arms 20 must be sufficient to cause the operation of the device by gravity.

It is to be noted that the device is operative to indicate the lowering of the normal fuel level to substantially a predetermined limit, but its especial sphere of usefulness is to prevent the exhaustion of fuel. below this limit when the fuel in the upper part of the hopper outside the range of the agitating wheel, is arched over so as to mislead an attendant as to the true conditions inside the hopper.

The upward limit of travel of arms 20 may extend to any suitable point, such, for instance,

as indicated by the dotted lines 202, in Fig. 2.

A sufiicient distance is allowed in prongs 30, to give blade 27' the necessary movement corresponding to the travel of arms20.

The length of these arms is such that they shall lie within the clearing zone of the agitator, which zone in this instance may be determined substantially by the outermost portions, radially, of the agitating wheel 15 and its sweep 18, which latter preferably extends transverse to the plane of rotation of the agitating wheel,

If it should be desired to give an alarm, instead of stopping the motor, switch 28 could be connected in circuit with an electric bell or other alarm. On the other hand, both the stopping of the motor and the sounding of an alarm might be provided for if preferred.

7 The joints between connecting rod 26 and

members

25 and 27, should allow the necessary latitude to prevent binding between the respective parts. ca

While a specific embodiment of this invention is herein shown and described, it is to be understood that various changes could be made therein without departing from the spirit and scope of the invention as defined in the claims.

Having fully described my invention, what I claim is:

l. The combination with a stoker having a hopper, a conveyor leading out of said hopper and an agitator revoluble in said hopper above the conveyor, of a control mechanism including an arm disposed to be raised and lowered within the circle described by said agitator, and means actuated by the movement of said arm for the purpose of controlling the motive power of said conveyor.

2. The combination with a stoker having a hopper, a conveyor leading out of said hopper and a revoluble wheel having agitating members describing a cylindrical space above said conveyor, 01' a control mechanism including an arm movable in the said cylindrical space and engageable by the said agitating members, means for imparting motion to said conveyor, and means whereby travel of said movable armis effective to start or stop, as the case may be,

said conveyor.

3. The: combination with a stoker or the like, having a hopper, a conveyor leading out of said hopper, an agitating wheel having a revoluble sweep above said conveyor, and a motor for driving said conveyor, of a control mechanism including an arm pivoted alongside said agitating wheel, said arm being engageable by the revoluble sweep, and having motion within the circular zone defined by revolution of said sweep, and an electric switch connected to said pivoted arm, said switch being operative to start and stop said motor.

4. The combination with a stoker or the like, 115 having .a hopper, a conveyor leading out of said hopper, and an agitating wheel having a revoluble sweep above said conveyor, of a control mechanismincluding a movable arm disposed for engagement by said sweep, and an electric switch 124] actuated by said movable arm, said switch being closed when the movable arm is raised to certain points, and opened when the movable arm is lowered to certain other points.

5. The combination with a stoker comprising 125 a container for fuel, a conveyor leading out of said container, and an agitator for loosening fuel above said conveyor, said agitator having a sweep extending transverse to the plane of rotation of the'agitator; of a movable arm engage- 130 able by said sweep and an electric switch operatively connected to said movable arm.

CALVIN KAY.