US3073450A

US3073450A - Apparatus for use in coal washing tanks

Info

Publication number: US3073450A
Application number: US821513A
Authority: US
Inventors: Schanne Lothar
Original assignee: Saarbergwerke AG
Current assignee: Saarbergwerke AG
Priority date: 1958-10-09
Filing date: 1959-06-19
Publication date: 1963-01-15
Anticipated expiration: 1980-01-15

Description

Jan. 15, 1963 L. scHANNE 3,073,450

APPARATUS FOR USE 1N coAL WASHING TANKS Filed June i9, 1959 3,073,450 APPARATUS FOR USE IN COAL WASHING TANKS Lothar Schanne, Elversberg (Saar), Saarland, Germany,

assigner to Saarbergwerke Aktiengesellschaft, Saarbrncken, Saarland, Germany, a company of Germany Filed .lune 19, 1959, Ser. No. 821,513 Claims priority, application France Oct. 9, 1958 12 Claims. (Cl. 209-455) This invention relates to improvements in apparatus for use in coal washing tanks for the separation of coal and shale in which the coal and shale are to be immersed in water and separated by their difference in density, the shale being heavier than the coal.

Coal washing tanks are usually provided with means for automatically regulating the discharge of the coal and shale and this regulation is achieved by means of a oat which is vertically displaceable to modify certain operating conditions of the tank. Where compressed air is utilized to impart a pulsatory motion to the water in the tank the float usually is arranged to control the amplitude of the pulsations imparted to the water. The float is arranged to be displaced in response to variations in the thickness of the shale layer in the tank and is so arranged that when this thickness increases, due either to feeding a larger quantity of material to the tank or to a higher proportion of shale being present in the raw material, the float rises and causes more intensive pulsations to be imparted to the water. Conversely, a reduction in the thickness of the shale layer causes the float to descend and results in a decrease in the amplitude of the pulsations imparted to thewater.

The amplitude of the pulsations imparted to the water is controlled either by controlling the supply of cornpressed air to a compressed air chamber or by controlling the escape of compressed air from the compressed air chamber, such control being effected in response t displacement of the piston through a piston and cylinder arrangement which transmits the movement of the float to suitable means controlling either the supply of compressed air to the chamber or the escape of compressed air from the chamber.

Many experiments have shown that, where the amplitude of the pulsations is controlled by controlling the supply of compressed air to the chamber, the apparatus does not respond accurately to small variations in the depth or thickness of the shale layer. Furthermore, where the amplitude of the pulsations is controlled by controlling' the escape or discharge of compressed air from the chamber, the apparatus only operates satisfactorily within narrow limits of variations in the depth or thickness of the shale layer and is unsatisfactory when these variations exceed such limits.

It is an object of the present invention to provide an improved apparatus for use in coal washing tanks for the separation of coal and shale which shall not be subject to the disadvantages referred to above,

Apparatus for use in a coal washing tank for the separation of coal and shale in which the coal and shale are to be immersed in water comprises means operable under the influence of compressed air supplied to a chamber to impart pulsations to the water, means displaceable in accordance with the thickness of the shale layer, first means responsive to displacement of the displaceable means to control the discharge of air from said chamber and second means responsive to displacement of the displaceable means outside predetermined limits to control the supply of compressed air to said chamber.

One embodiment of the present invention will now be described by Way of example, reference being made to the accompanying drawings in which:

FIG. l is a diagrammatic sectional view of part of a States Patent O Patented Jan. 15, 1963 ICC coal washing tank provided with mechanical means in the form of a piston for imparting pulsatory movements to the liquid in the tank, and

FIG. 2 is a diagrammatic view on a larger scale of a regulating or controlling device for a coal washing tank which is provided with means for admitting compressed air to produce pulsatory movements of the liquid in the tank.

The coal washing tank illustrated in FIG. l is divided by a central separating wall 1a into two compartments 1b and 1c which communicate with each other at their lower ends below the separating wall 1a. Water is disposed in the tank and a piston 2 is slidably disposed in` the compartment 1c and has a pulsatory motion imparted to it in known manner, the piston 2 communicating its pulsations to the water in the tank. The pulsatory motion may be imparted to the water in the tank by compressed air introduced into a chamber A located above the compartment 1c.

The material to be separated is supplied to the compartment 1b, lthe heavier shale 3 falling on to a grating 4 whilst the pieces of coal 3a .are supported on the shale layer. A oat 5 (FIG. 2) rests on the shale layer and is carried on the lower end of a rod 6 slidable vertically in a guide 7. The upper end of the rod 6 is articulated at 8 to a rod 9 which is itself articulated at 10 to the shaft 1,1 of a slide valve 12 of known type. The slide valve 12 contains two piston-

type valve members

13 and 14 which are secured on the shaft 11, `and it receives -uid under pressure yfrom a pipe 15a opening into the valve between the two piston-

type valve members

13 and 14. Two interconnected pipes 15b and 15e` open one int-o each end of the valve 12 yfor the purpose of discharging fluid therefrom. Two

outlet pipes

16 and 18 extend from the valve 12 respectively to the upper end of a cylinder 17 4and the lower end thereof, the

outlet pipes

16 and 18 opening into the valve 12 at such locations as to be normally closed by the piston-type valve members y13 and 14 respectively when the shaft 11 is in its normal position and in such manner that displacement of the shaft 11 in one direction places the outlet pipe 16 in communication with fluid from the pipe 15a whilst the outlet pipe 18 is placed in communication with the discharge pipe 15C and displacement of the shaft 11 in the opposite direction vplaces the `outlet pipe 18 in communication with huid .from the pipe 15a' whilst the outlet pipe 16 is placed in communication with the discharge pipe 15b. A piston 19 is displaceable in the cylinder 17 and is mounted on a rod 20 which carries at its lower end a valve member 21 adapted to bear against a seat 22 surrounding an outlet orice 23 in the chamber A, through which oritice the compressed -air in the chamber can escape or be discharged.

The rod 20 is articulated at 24 to a rod 25 which itself is articulated to a triangular plate 26 pivotally carried at one corner lon 1a xed pin 27. A second corner of the plate 26 is articulated to la rod 29 carrying a stud 30 at its end.

The stud 30 is :displaceable in a groove 31 formed in a disc 32 carried on the exterior of a pipe 33 through which compressed air is admitted to the chamber A. The longitudinal walls `defining the groove 31 conform to arcs of circles concentric about the axis of a pin 34 secured centrally of the disc 32 and extending through the pipe 33 normal to the axis thereof. The pin 34 is rotatable -about its axis, suitable bearing surfaces being provided in the wall of the pipe 33, and carries a circular butterfly valve 35 disposed within the pipe 33 and having a diameter substantially equal to the internal diameter of the pipe 33V so as to be capable of substantially closing the latter, the butterfly valve 35 being secured to the pin 34 substantially along a diameter. The plane of the )butterfly valve is sub-v` stantially normal to that of the disc 32 and rotation of the latter produces a corresponding rotation of the former.

The pin 34 further carries a pointer 36 extending normal to its axis and movable over a scale 37 substending an angle of 90 to the `axis of the pin 34 and bearing graduations from to 1, the pointer 36 being arranged to indicate the graduation 0 when the pipe 33 is closed by the butterfly valve 35 and the graduation l when the pipe 33 is Wholly open.

The disc 32 is formed with a second groove 38 the longitudinal walls of which conform to arcs of circles concentric about the `axis of the pin 34. A stud 39 is displaceable in the groove 3S and is carried on a restoring spring 40 secured by its lower end 41 to the pipe 33.

The operation of the apparatus will now be described:

When the thickness of the shale layer 3 increases, such an increase being due either to an increase in the quantity of material supplied to the tank or to the material containing a larger quantity of shale, the float 5 rises moving the rod 6 upwardly and displacing the shaft 11 of the slide valve 12 to the right in FIG. 2 towards the position indicated in dotted lines. Thus the pipe 16 is uncovered and fluid under pressure from the pipe 15a is conveyed through the pipe 16 to the upper end of the cylinder 17 causing the downward displacement of the piston 19. The downward :displacement of the piston 19 causes a corresponding downward displacement of the valve member 21 towards its seat 22 and reduces the escape of air through the orifice 23. Simultaneously, the downward displacement of the piston 19 pivots the triangular plate 26 about the pin 27 and through the rod 29 displaces the stud 30 in the groove 31 without rotating the disc 32.

Thus, if the thickness of the shale layer 3 increases slightly, a first regulating effect is obtained by reducing the escape of compressed lair from the chamber A and thereby increasing the amplitude of the pulsations imparted to the water in the tank to reduce the thickness of the shale layer.

If the thickness of the shale l-ayer 3 continues to increase the float 5 rises correspondingly and the orifice 23 is closed more and more lby the valve member 21 whilst the stud 30 continues to lbe displaced towards the lower end of the groove 31 until a stage is reached when the stud 30 engages the lower end of the groove 31 4and further displacement of the stud 30 produces a corresponding rotation of the disc 32 and of the buttery valve 35 in the sense to increase the supply of compressed air to the chamber A. Movement of the disc 32 is opposed by the spring 40 and is communicated to the pointer 36 which is moved towards the graduation 1.

Thus an increase in the thickness of the shale layer 3 beyond a predetermined limit brings a second regulating effect into operation by increasing to admission of compressed air to the chamber A whilst reducing the escape of compressed air therefrom thereby greatly increasing the amplitude of the pulsations imparted to the water. The thickness of the shale layer is accordingly reduced until a value is reached when the butterfly valve 35 appreaches its normal or mean position under the influence of the spring 40, in which position the pointer 36 indicates the graduation 1/2 on the scale 37.

Conversely a slight reduction in the thickness of the shale layer 3 causes the float 5 and the rod 6 to descend, the shaft 11 then being displaced to the left in FIG. 2 thereby causing fluid under pressure to be fed from the pipe 15a to the lower end of the cylinder 17 through the pipe 18. This causes the piston 19 to rise and lifts the valve member 21 away from its seat 22 to increase the amount of air escaping from the chamber A through the orifice 23 and thereby reducing the amplitude of the pulsations imparted to the water and Vhence increasing the thickness of the shale layer.

lf the thickness of the shale layer decreases below a predetermined limit, the corresponding motion of the piston 19 causes the plate 26 to rotate to the extent that the stud 3) engages the upper end of the groove 31 and rotates the disc 32 and the butterfly valve 3S in the counter-clockwise direction to tend to close the passage through the pipe 33. Simultaneously the pointer 36 moves towards the graduation 0. Such rotation of the butterfly valve 35 reduces the supply of compressed air to the chamber A Whilst the escape therefrom is increased by the lifting of the valve member 21 and this results in a considerable reduction in the amplitude of the pulsations imparted to the water and hence an increase in the thickness of the shale layer up to a predetermined value corresponding to normal operation of the tank.

It will be understood that, as the float 5 is itself subjected to the pulsatory movement of the water, the

pistons

13 and 14 are arranged not to be displaced due to slight variations of the float corresponding to normal pulsatory movement or they are so dimensioned as not to uncover the

pipes

16 and 18 unless the motion imparted to the shaft 11 is greater than that normally imparted thereto due to the pulsatory movement of the water.

It will be appreciated that the disc 32 may be formed with a plurality of concentric grooves corresponding to the groove 31 but each of a different length than the other so that the degree of movement permitted to the piston 19 before the valve 3S is operated may be selected by engaging the stud 30 in the appropriate one of such grooves.

What I claim is:

1. Apparatus for use in a coal washing tank for the separation of coal and shale in which the coal and shale are to be immersed in water, said apparatus comprising, in combination, a chamber having a discharge orice, means for admitting compressed air to the chamber so that the compressed air admitted to said chamber may impart pulsations to the water, means displaceable in response to changes in the thickness of the shale layer, first means responsive to displacements of said displaceable mean for controlling the discharge of air through said orifice, and second means responsive to displacements of said displaceable means beyond a predetermined upper limit and below a predetermined lower limit for controlling the admission of compressed air to said chamber.

2. Apparatus according to claim l wherein said rst means comprises a valve member movable towards and away from said orifice for varying the discharge of air from said chamber in accordance with the displacement of the displaceable means.

3. Apparatus according to claim 2, further comprising a cylinder, a piston operatively connected with said displaceable means and displaceable in the cylinder in response to the displacement of the displaceable means, and a connection between said piston and said valve member.

4. Apparatus according to claim 3, wherein the operative connection between said piston and said displaceable means comprises a slide valve operatively connected to the displaceable means for controlling the flow of a compressed fluid to said cylinder and for thereby controlling the displacements of said piston in the cylinder.

5. Apparatus for use in a coal washing tank for the separation of coal and shale in which the coal and shale are to be immersed in water, said apparatus comprising, in combination, a chamber having a discharge orifice, means comprising a pipe for admitting compressed air to said chamber so that the compressed air may impart pulsations to the water, means displaceable in accordance with the thickness of the shale layer, means responsive to the displacement of the displaceable means for controlling the discharge of air through said orifice, and a valve disposed in said pipe and operatively connected with said displaceable means, said valve responsive to displacement of the displaceable means beyond a predetermined limit for controlling the supply of compressed air to said chamber.

6. Apparatus according to claim wherein the operative connection between said displaceable means and said valve comprises linkage means incorporating a lost motion connection.

7. Apparatus for use in a coal Washing tank for the separation of coal and shale in which the coal and shale are to be immersed in Water, said .apparatus comprising, in combination, a chamber having a discharge orifice, a pipe connected to the chamber for admitting compressed Aair thereto so that the compressed air admitted to said chamber may impart pulsations to the water, means dis placeable in accordance with the thickness of the shale layer, a cylinder, a piston displaceable in the cylinder in accordance with thesupply of pressure iuid to the ends thereof, a slide valve operatively connected with and responsive to displacement of said displaceable means for controlling the supply of a pressure fluid to the cylinder and for thereby displacing said piston in response to displacements of said displaceable means, a valve member connected to said piston and movable towards and away from said discharge orice for controlling the discharge of air therefrom in response to displacements of said`displaceable means, a valve disposed in said pipe for controlling the admission of compressed air to said chamber, and a lost motion connection between said valve and said piston.

8. Apparatus according to claim 7 wherein said lost motion connection comprises an element connected to said valve and having a groove formed therein, linkage means connected with said piston, and a stud connected with said linkage means and shiftably received in said groove.

9. Apparatus according to claim 8 vwherein said element is a disc comprising a pin rotatably mounted in said pipe and connected with said valve, said pin rotating said valve when said stud engages an end of the groove in said disc.

l0. Apparatus according to claim 9 wherein the longitudinal walls of said disc dening said groove conform to arcs of circles concentric about the axis of the pin.

l1. Apparatus according to claim 8 wherein said element is formed with a second groove and further comprising a stud displaceably received in said second groove and a restoring spring connected with said pipe and said stud.

l2. Apparatus for use in a coal washing tank for the separation of coal and shale in which the coal and shale are to be immersed in water, said apparatus comprising, in combination, a chamber having a discharge orifice, a pipe connected to said chamber for admitting compressed air thereto so that the compressed air may impart pulsating movements to the water, means displaceable in response to changes in the thickness of the shale layer, a cylinder, a piston displaceable in said cylinder in accordance with changes in the supply of a pressure huid to the ends of said cylinder, a slide valve responsive to displacement of said displaceable means for controlling the supply of pressure iiuid to said cylinder, a valve member operatively connected 4to said piston and movable towards and away from said discharge orifice in accordance with the displacement of said vpiston to thereby control the discharge of compressed air from said chamber in response to displacements of said displaceable means, a circular buttery valve disposed in said pipe for controlling the admission of compressed air to said chamber, a pin secured to and extending along a diameter of said butterily valve, said butterfly valve rotatable with saidv pin, a disc formed with a groove and connected for rotation with said pin externally of said pipe, a stud displaceably received in said groove, and linkage means connecting said stud to said piston whereby a displacement of the piston beyond a predetermined limit displaces said stud into engagement with an end of said groove to rotate said butterfly valve and to thereby control the admission of compressed air to said chamber in response to displacements of said displaceable means.

References Cited in the tile of this patent UNITED STATES PATENTS 2,035,750 Hirst Mar. 31, 1936 2,169,544 Vissac Aug. l5, 1939 2,177,537 Sloan Oct. 24, 1939 2,828,015 Vissac Mar. 25, 1958 2,889,045 Turpin June 2, 1959

Claims

1. APPARATUS FOR USE IN A COAL WASHING TANK FOR THE SEPARATION OF COAL AND SHALE IN WHICH THE COAL AND SHALE ARE TO BE IMMERSED IN WATER, SAID APPARATUS COMPRISING, IN COMBINATION, A CHAMBER HAVING A DISCHARGE ORIFICE, MEANS FOR ADMITTING COMPRESSED AIR TO THE CHAMBER SO THAT THE COMPRESSED AIR ADMITTED TO SAID CHAMBER MAY IMPART PULSATIONS TO THE WATER, MEANS DISPLACEABLE IN RESPONSE TO CHANGES IN THE THICKNESS OF THE SHALE LAYER, FIRST MEANS RESPONSIVE TO DISPLACEMENTS OF SAID DISPLACEABLE MEAN FOR CONTROLLING THE DISCHARGE OF AIR THROUGH SAID ORIFICE, AND SECOND MEANS RESPONSIVE TO DISPLACEMENTS OF SAID DISPLACEABLE MEANS BEYOND A PREDETERMINED UPPER LIMIT AND BELOW A PREDETERMINED LOWER LIMIT FOR CONTROLLING THE ADMISSION OF COMPRESSED AIR TO SAID CHAMBER.