US2185686A - Fuel feed control mechanism - Google Patents

Description

Jan. 2, 1940. i B. F. BOWER 2,185,686

FUEL REED comm. MECHANISM Filed Nov. 16, 1938 2 Sheets-Sheet 1 29 fizz/6711 27:

' fiyrazz I .5 0 we?" 27 Q 33 //1Mz- Jan. 2, 1940. ow I 2,185,686

FUEL FEED CONTROL MECHANISM F iled Nov. 16, 1938 2 Sheets-Sheet 2 jyron J 3021/67 22 Y yaw Patented Jan. 2, 1940 UNITED STATES FUEL FEED CONTROL .MEonANisM Byron F. Bower, St. Charles, IlL, assignor to; The

Howell Company, St. Charles, Ill., 21. corporation of Illinois Application November 16, 1938, ea; No. 240,721

9 Claims.

The present invention relates to furnaces, and particularly to the fuel feeding mechanism by which coal or similar types of fuel are fed into the fire box of the furnace. The present invention is particularly applicable to the pusher type of fuel feeding device wherein a reciproeating pusher block is located in a coal hopper and acts to advance fuel to an opening which leads to the furnace chamber. Although not limited thereto, the present invention is par-- ticularly applicable to the spreader type of fuel feeding means by which coal is thrown into the fire box and spread over the grates. The fuel throwing means may be of any suitable type, insofar as the present invention is concerned.

It is the purpose of the present invention to provide an improved means for adjusting the movement of the pusher to advance more or less coal where the driving unit for the pusher includes a motor or other suitable means operating it at a predetermined speed.

The present invention contemplates the provision in a fuel feeding mechanism of the type described of a rock shaft which is connected to the pusher block and means for variably moving the rock shaft from a constantly driven drive shaft. The contemplated means comprises two cam arms, one of which drives the rock shaft in proportion to its movement, and the other of which is driven from the constantly moving shaft in proportion to its movement. The two cam arms have opposed cam surfaces receding from each other toward the outer ends of said arms, and a cam pin member is movably mounted between the cam surfaces. Movement of the pin member preferably is controlled automatically from a suitable type of commercial controller, such as those responsive to variations in steam pressure. A control arm which carries the cam pin member may be pre-set or adjusted for any particular requirement.

The present invention contemplates a control device of the character described wherein the separation of the opposed cam faces is calculated to cooperatewith the damper controlling the flow of gases from the furnace so that the amount of coal fed is varied in direct proportion to the variation in damper opening.

It is a purpose of the present invention to provide a simple and effective control mechanism comprising two opposed cam arms, one of which is driven from the drive source, and the other of which drives the rock shaft that actuates the coal pusher block wherein the two cam arms are limited as to separation and are adjustable as to their approach to each other, the last named adjustment being manually or automatically operated. r y

The features and advantages of the present invention will appear more fully as the description proceeds, reference being had to the accompanying drawings wherein a preferred form of the invention is shown. It is to be understood, however, that the drawings and description are illustrative only and are not to be taken as limiting the invention except insofar as it is limited by the claims.- I

In the drawings, Fig.- 1 is a fragmentary sectional View taken through the lower part of a coal hopper and through the coal feeding mechanism by which coal is advanced to a furnace and thrown into the fire box of the furnace;

- Fig. 2 is a view inside elevation of the mechanism employed to operate the pusher block which feeds the fuel from the hopper;

Fig. 3 is a fragmentary plan view showing the mechanism illustrated in side elevation in Fig. 2;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2, and

.Fig. 5 is a fragmentary sectional View taken on the line 5-5 of Fig. 2. I Referring now to the drawings, the present invention is embodied in the fuel feeding mechanism of a furnace that burns coal, coke, or a similar fuel. In the device as shown, the numeral l0 indicates the front wall of a furnace to which there is bolted a door casting H. The door casting H supports a framework l2 that carries a mechanical" spreader for throwing coal into the fire box of the furnace and spreading it over the grates therein; The details of the mechanism for spreading are not claimed herein, but for the purpose of understanding they will. be described briefly. The mechanical spreader com prises a rotating shaft l3 which carries a number of spreader'paddle's such as indicated at M and 15. These paddles strike coal that falls into a deflector housing Hi. The coal is stored in a hopper l1 and is fed from this hopper by means of a pusher block I8 located in the bottom of the hopper. The pusher block 18 rides on a base plate 19 which projects over the deflector housing 16 as indicated at Zil. An agitator bar 2t forms a part of the pusher block I8 for working the coaldown in front of the pusher block sothat it. can be advanced over the projection 20 of .the base plate IS.

-The means for operating the pusher block I8 comprises an arm 22 and a rock shaft 23 which is driven from a suitable source of power. The present invention concerns itself with the means for operating the rock shaft 23 from a continuously driven shaft, or motor, or other source of power.

Referring now to Figs. 2-5 inclusive, the rock shaft 23 is provided with a cam arm 24 which is keyed to the shaft 23 by a suitable key 25. A second cam arm 26 has a hub portion 21 which is journalled on the shaft 23 between two hub portions 28 and 29 of the cam arm 24. The portions 28 and 23 act as a guide for the hub 2'! of the cam arm 26. The two cam arms 24 and 26 are held against separating by means of a latch 30 which has two cars 3| and 32 projecting down over the upper end of the cam arm 24 and pivoted to the cam arm 24 by a shaft 33. The latch 30 has a hook 34 at its free end, and this hook engages a catch portion 35 at the top of the cam arm 26. The upper end of the cam arm 26 is rounded as shown at 36 so that the latch 30 will ride on this upper end as the cam arm 26 moves toward and away from the cam arm 24.

Thecam arm 26 is driven from a drive shaft 31 which is operated from a suitable motor, not shown. This motor is preferably the same motor which drives the rotor shaft 13. The shaft 37 has an eccentric 38 thereon. An arm 39 has a hub 46 journalled on the eccentric 38. The other end of the arm 39 is bifurcated to provide two spaced hub portions 4| and 42 that receive the cam arm 26 between them. A shaft 43 connects the cam arm 26 with the hub portions 4| and 42. p

The cam arms 24 and'26 have opposed cam faces 44 and 46 which cam faces are adapted to be held apart by a cam pin 45. It will be evident from an inspection of Fig. 2 that as the pin 45 moves upwardly from the position shown in full lines in Fig. 2 to the position shown in dotted lines in Fig. 2, the cam arm 26 will be permitted to move more relative to the cam arm 24 without effecting any movement of the cam arm 24. When the pin 45 is in the position shown in full lines in Fig. 2, no movement of the cam arm 26 is permitted toward the cam arm 24. The two arms must move together. Now, however, as the pin 45 is lifted, it fails to bridge the gap between the faces 44 and 46. Therefore, the cam arm 26, when it is moving toward the cam arm 24, will first take up the space be- I tween the faces 44 and 46 that is in excess of the diameter of the pin 45. When this space is all taken up, then the two arms will be caused to move in unison. Then upon the return movement of the cam arm 26 the two cam arms will separate until the hook 34 on the latch 30 engages the catch 35 on the cam arm 26. Vertical adjustment of the pin 45 can thus be made to take care of the angular movement imparted to the cam arm 24 and, therefore, the angular movement imparted to the shaft 23.

In order to control the position of the pin 45, this pin is suspended by integral links 4! and 48 from a control lever 49. The control lever 49 has a hub portion 50 which is journalled upon a pin 5!. Two arms 52 and 53 project from the hub 56 and are bifurcated at their free ends, as shown at 54 and 55 to receive the links 4! and 48. Pins 56 and 5'! pivotally mount the links 41 and 48 in the bifurcated ends 54 and 55.

The control lever 49 has a bifurcated end portion 58 which is adapted to be connected to a control link 59 leading to a suitable type of commercial controller, steam responsive or otherwise.

As is common with controllers of this character, they adjust the damper opening and the coal feed and air supply in response to some regulating factor such as the steam pressure in the boiler.

In order to manually control the coal feed and to adjust it properly for the automatic operation, I mount the pin 5| on a hand lever 60.

The hand lever 60 is pivoted on a stub shaft 6|. The hand lever is provided with a laterally extending ear 62 having an elongated slot 63 that receives a screw threaded stud 64. A clamping nut 65 having a hand grip 66 is provided for r clamping the ear 62 against the side wall of the '15 framework I2. I

It is believed to be evident that by vertically adjusting thehand lever 60 the position of the pin 45 can be varied to suit any particular oper-- ating conditions. In fact, it can beused to move the pin upso far that movement of the arm 24 inresponse to movement of the cam arm 26 practically ceases. This would mean that even though the shaft 31 continued to operate, the pusher 56 would cease to feed coal and the rotor 83 would receive no coal. The design-of the cam faces 44 and 46 is calculated to produce a variation in coal fed which is proportional to the variation in damper opening as the damper is opened and closed in unison with vertical movement of the pin 45.

The simplicity of the control mechanism hereinbefore described does not limit its flexibility since it is possible with the simple adjustments of the lever arm 66 to vary the stroke of the pusher l8 from maximum stroke to practically no movement at all. There are no set screws to adjust, and the range of movement of the pin45 is sufficiently great to make the manual adjustment thereof sensitive enough for all operating conditions."

From the foregoing description it is believed on said rock shaft, a second cam arm pivoted on said rock shaft, said arms having opposed cam faces, means for rocking said pivoted cam arm through a predetermined arc, and means for variably rocking the first named cam arm' in response to the movement of the pivoted cam arm, said means comprising a latch secured on one arm and hooked over a catch on the other arm to limit the spreading of said arms and a cam pin interposed between said cam faces and movable lengthwise with respect to said faces to vary the limit of approach of the pivoted arm to the arm fixed on the rock shaft.

2. In a fuel feeding mechanism for furnaces, a

rock shaft, means for operating said rock shaft,

said means comprising a cam arm fixed to said rock shaft, a second cam arm pivoted on said rock shaft, said two cam arms having opposed cam surfaces, a member interposed between said cam surfaces, means for moving said member toward and away from the rock shaft, means limiting the angular separation of said cam arms, and

power driven means rocking said pivoted cam arm.

3. In a fuel feeding mechanismv for furnaces, a rock shaft, means for operating said rock shaft, said means comprising a cam arm fixed to said rock shaft, a second cam arm pivoted on said rock shaft, said two cam arms having opposed cam surfaces, a member interposed between said cam surfaces, a control lever for moving said member toward and away from the rock shaft, means limiting the angular separation of said. cam arms, and power driven means rocking said pivoted cam arm.

4. In a fuel feeding mechanism for furnaces, a rock shaft, means for operating said rock shaft, said means comprising a cam arm fixed to said rock shaft, a second cam arm pivoted on said rock shaft, said two cam arms having opposed cam surfaces, a member interposed between said cam surfaces, acontrol lever connected to said member for moving said member toward and away from the rock shaft, manually adjustable means supporting said control lever, means limiting the angular separation of said cam arms, and power driven means rocking said pivoted cam arm.

5. In a fuel feeding mechanism for furnaces, a rock shaft, means for operating said rock shaft, said means comprising a cam arm fixed to said rock shaft, a second cam arm pivoted on said rock shaft, said two cam arms having opposed cam surfaces, a member interposed. between said cam surfaces, a control means connected to said memher for moving said member toward and away from the rock shaft, a manually adjustable lever, said control means being movably mounted on said manually adjustable lever, means limiting the angular separation of said cam arms, and power driven means rocking said pivoted cam arm.

6. In a fuel feeding mechanism for furnaces, a rock shaft, means for operating said rock shaft, said means comprising a cam arm fixed to said rock shaft, a second cam arm pivoted on said rock shaft, said two cam arms having opposed cam surfaces, a member interposed between said cam surfaces, a control lever for moving said member toward and away from the rock shaft, a manually adjustable lever, said control lever being pivoted on said manually adjustable lever, means limiting the angular separation of said cam arms, and power driven means rocking said pivoted cam arm.

7. In a stoker, a rock shaft and drive means for said rock shaft, said drive means comprising a cam arm fixed on said rock shaft, a second cam arm pivoted on said rock shaft, said arms having opposed cam faces'means for rocking said pivoted cam arm through a predetermined arc, and means connecting said arms for variably transmitting the rocking motion of the pivoted cam arm to the first named arm, said last named means comprising a bearing member suspended between said cam faces and adjustable lengthwise thereof.

8. In a stoker, a rock shaft and means for operating said rock shaft, said means comprising an arm connected to said rock shaft, a second arm movable toward and away from said first named arm and pivoted on said rock shaft, means for rocking said second arm and means connecting said arms for variably transmitting the rocking motion of the second arm to the first arm, said last named means including cam surfaces on said arms and an adjustable control means engaging said cam surfaces and movable lengthwise thereof for variably limiting the movement of one of said surfaces relative to the other.

9. In a stoker, a rock shaft, a drive shaft, an arm connected to'said rock shaft, a second arm for actuating said first named arm, an eccentric on said drive shaft, a link connecting said eccentrio with said second arm, means limiting the separation of said arms, and adjustable means limiting the approach of said second arm to the first arm, said adjustable means comprising a pin interposed between said arms and movable lengthwise thereof, and cam faces on said arms for engaging said pin. 1 1

BYRON F. BOVVER.

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