US2641208A - Automatically controlled ash removing grate - Google Patents

Description

June 9, 1953 F. J. WEST ETAI.

AUTOMATICALLY coNTRoLLED Asl-x REMovING GRATE Filed Aug, v23, 1949 2 Sheets-Sheet 1 n f f /l \b NN ////////////////W m f Am June 9, 1953 F. J. .wx-:sT ETAL AUTOMATICALLY CONTROLLED ASH REMOVING CRATE Filed Aug. 2s, 1949 2 Sheets-Sheet 2 Patented June 9, 1953 AUTOMATICALLY CONTROLLED ASH REMOVING GRATE Frederick Joseph West and Ernest West, Manchester, England, assignors to Wests Gas Improveinent Company Limited, Manchester, England, a British company Application August 23, 1949, Serial No. 111,906 In Great Britain September 6, 1948 6 Claims.

This invention relates to gas producers of the type known as mechanical producers in which the grate is revolved in order to elect extraction of ash.

The object of the present invention is to provide automatic means for controlling the ash level in the producer within narrow limits which increases the efficiency of the producer and enables the dimensions of the latter to be reduced for a given throughput.

The invention comprises the arrangement in the water jacketed wall of the producer at about the desired level of the top of the ash bed, of a bulb containing an expansible fluid which through suitable means controls the speed of Operation of the ash extracting grate in order to maintain the level of the top of the ash bed where desired.

The invention further comprises the provision of means for withdrawing the bulb to a greater or less extent into the water jacket should the temperature to which the bulb is subjected become excessive.

The invention further comprises the provision of over-riding hand control means which permit the grate speed to be hand adjusted as required.

The invention further comprises the arrangement in which the uid from the bulb acts upon one side of a diaphragm, the other side of which displaces a fluid which acts upon a plunger controlling the rate of outflow of the exhaust fluid from a hydraulic motor driving the producer grate.

The invention further comprises the interconnection of the plunger by a lever with a second lever which can be held in an inoperative position by a hand operated cam or its equivalent when the lever end moves in an elongated slot in the second plunger, the latter when released balancing the hydraulic pressure on the rst plunger and allowing the latter to be moved by hand to control the speed of the motor driving the producer grate.

The invention further comprises the arrangement of the lever upon a shaft which turns an indicator of grate speed, with braking means preventing free movement of said shaft when the second plunger is released to allow of hand control of the speed of the grate.

The invention further comprises connecting the diaphragm casing rigidly to a cylinder in which is a xed abutment, with a spring between the cylinder and abutment so arranged that when the pressure of fluid produced by move- CII ment of the diaphragm is excessive, such pressure acting between the cylinder and abutment against the spring pressure will cause the diaphragm casing to move to withdraw the bulb to a greater or less extent into the water jacket around the producer and so prevent damage to the bulb.

Referring to the accompanying explanatory drawings:

Figure 1 illustrates in sectional elevation a portion of a gas producer with control means thereon in accordance with this invention.

Figure 2 illustrates the control means to an enlarged scale and in greater detail.

Figure 3 is a view at right angles to Figure 2 showing a further portion of the control means.

It will be appreciated that on the drawings Figures 2 and 3 are diagrammatic only and not to scale. They serve to illustrate the general arrangement of the grate control means in accordance with this invention.

VThe producer comprises a revolving grate a, a gas oi take by through which the producer gas is delivered across and through one side of the producer, a fuel feed inlet c and a water jacketed combustion zone.

We provide in the water jacketed wall d of the producer at about the desired level oi the top of the ash bed a bulb e containing a suitable expansible fluid and cause such fluid through suitable means to control the speed of operation of the ash extracting grate in order to maintain the level of the top of the ash bed Where desired.

As shown in detail in Figure 2, the expansible fluid presses upon one side of a diaphragm e1, the other side of which presses upon a fluid in a pipe f and casings g and h. If the pressure of the uid in the casing g is suicient to overcome the spring i which bears at one end against the head y' of the iixed abutment lc, the casing is moved to the right in Figure 2 and by means of the rigid pipe m carries with it the casing n of the diaphragm e1 and the mercury or like bulb e, so that such bulb is drawn back a short distance from the hot zone of the producer and is therefore subjected to a lower temperature. This arrangement prevents damage to the bulb due to exposure to excessive temperature. The fluid pressure in the pipe f also tends to depress the plunger o in the casing h against the pressure of the spring p. The position of the plunger determines the speed of the motor which turns the revolving grate u, and so the rate of ash extraction from the producer. For example, the grate may be turned by a hydraulic motor, indicated schematically at I9, Figure 1 and the rate of reciprocation of the motor as described below may be regulated by controlling the rate at which the hydraulic uid can pass to exhaust by pipe 20. Thus in Figure 2, the plunger o has a peripheral groove q thereon and the hydraulic iluid which is exhausting to atmosphere has to pass from the branch r to the branch s via such peripheral groove, If the plunger o is in a raised position, the length of the peripheral groove through which the fluid has to travel is short and so very little obstruction or throttling of the exhaust occurs; therefore the hydraulic motor operates with maximum speed, whereas when the plunger o is in its lower position as shown, the exhausting fluid has to pass through a considerable length of the peripheral groove which acts to obstruct or throttle such exhaust and therefore to slow down the speed of the hydraulic motor driving the grate a, of the producer.

The plunger o is connected by the lever t tov a second plunger u which can be supportedy and put out of action byv a cam v. When so supported, the end of the lever t can move freely inthe slot v1 in the plunger u` without moving the latter. The cam v is turned by a handle or hand wheel w, Figure 3 on a shaft which has a pointer y thereon to indicate the position of thev cam.v

When the cam c is removed from the position in which it supports the plunger u, the latter is freed so that the hydraulic pressure exerts a balancing action between the plungers o and u, and then the lever t can be operated by hand to control the speed of the motor driving the grate a.

The spring p, when the cam v is removed from beneath the plunger u, will tend to turn the lever t and the shaft a on which it is secured and so through the quadrant Z, pinion 3, andk shaft 4 turn the indicator 5 moving over the dial 8 which gives indications of grate speed. To'- prevent the setting of the parts being altered automatically by the spring p when the cam v is released from the plunger u, we provide a cam I on the. shaft 9:

which operates a lever 8 fulcrummed at 9 andy y carrying a brake pad I i! adapted to engage a.

brake drum H on the indicator shaft 4. When the cam v holds the plunger u in its raised position, the cam 'l holds the brake pad I0 clear of the drum l I, but when the cam c is moved clear of the plunger u, the pad I0 engages the drum l I and prevents the shaft 4 turning except under the -action of the hand wheel I2 thereon which can be used to reset the plungers o and u and so vary the speed of the motor operating the producer grate.

It will be seen, therefore that the production of a high temperature at the bulb e causes during normal working, when the cam c is holding up the plunger u, the plunger o to be depressed with the result that the speed of the motor driving the producer grate is reduced as before explained whilst if the temperature at the bulb e is excessive, the bulb itself is drawn back away from the furnace zone and further into the water jacketed zone by the action of the parts g, z', k and m as previously explained, so that damage to the bulb is obviated. These high and excessive temperature conditions at the bulb e indicate that the ash is being extracted too rapidly from the producer furnace so that the high temperature zone is becoming lower and nearer to the grate a. On the contrary, if the temperature at the bulb e falls below a predetermined degree, it indicates that the ash is building up on the grate a and the high temperature zone of the furnace is rising. The action of the duid in the bulb e together with the associated parts is to move the plunger o to decrease the length of the peripheral slot q and so, as before explained, to speed up the motor driving the grate a. The ash level then falls and with it the high temperature Zone of the furnace.

What we claim is:

l. In a gas producer having a grate, a hydraulic motor for turning the grate in order to effect extraction of ash from the base of the producer, andr a water j acketed Wall, surrounding the combustion zone, the provision of a bulb containing an expansible duid, in the water jacketed wall at about the desired level of the top of the ash bed, a diaphragm casing, a diaphragm dividing the casing into two parts, one part being in communication with the bulb, a housing in communication with the other part of the casing, a plunger in the housing adapted to be displaced by the diaphragm through the medium of a luid, the plunger controlling the rate of outflow of the exhaust uid from the hydraulic motor driving the producer grate.

2. In a gas producer as claimed in claim l, the interconnection of the plunger by a lever with a second plunger, having an elongated slot and which can be held in an inoperative position by a hand operated cam, when the lever end moves in the elongated slot in the second plunger, the latter when released balancing the hydraulic pressure on the first plunger and allowing the latter to be moved by hand to control the speed of the motor driving the producer grate.

3. In a gas producer as claimed in claim l, the arrangement of the lever upon a shaft which turns an indicator of grate speed, with braking means preventing free movement of said shaft when the second plunger is released to allow of hand control of the speed of the grate.

4. In a gas producer as claimed in claim 1, a cylinder to which the diaphragm casing is rigidly connected, a xed abutment in the cylinder, and a spring between the cylinder and abutment so arranged that when the pressure of duid produced by movement of the diaphragm is excessive,

such pressure acting between the cylinder and abutment against the spring pressure will cause the diaphragm casing to move to withdraw the bulb to a greater or less extent into the water jacket around the producer and so prevent damage to the bulb.

5. In a gas producer having a grate which is turned by power in order to elect extraction of ash from the base of the producer, and a water jacketed wall surrounding the combustion zone, the provision of a bulb containing an expansible fluid, in the water jacketed wall at about the desired level of the top of the ash bed, a pressure responsive device in a casing connected with said bulb, and means actuated by said device for controlling the speed of operation of the ash extracting grate in order to maintain the level of the top of the ash bed where desired, and means for withdrawing the bulb to a greater or less extent into the water jacket should the temperature to which the bulb is subjected become excessive.

6. In a gas producer having a grate which is turned by power in order to effect extraction of ash from the base of the producer, and a water jacketed wall surrounding the combustion zone, the provision of a bulb containing an expansible fluid, in the water jacketed Wall at about the desired level of the top of the ash bed, a pressure responsive device in a casing connected with said n) bulb, and means actuated by said device for controlling the speed of operation of the ash extracting grate in order to maintain the level of the top of the ash bed where desired, and hand control means which over-ride the automatic `control means and permit the grate speed to be hand adjusted.

FREDERICK JOSEPH WEST. ERNEST WEST.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Wallis Jan. 11, 1910 Daae July 14, 1931 Van Ackeren Sept. 13, 1932 Corbett Sept. 18, 1934 Wolfe Dec. 11, 1934 Grine et al Dec. 3, 1935 Reid, Jr Mar. 23, 1937

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