US2078752A - Sand and mud separator and mixer for well drilling - Google Patents

Description

Sheec s-Sheet l JVVENTDJL JI'CHRISTENSEN April 27, 19371.

c, T. CHRISTENSEN SAND/AND MUD SEPARATOR AND MIXER FOR WELL DRILLIN Filed April 15 1955 April 1937. c. T. CHRISTENSEN 2,078,752

SAND AND MUD SEPARATOR AND MIXER FOR WELL DRILLING Filed April 13, 1933 2 Sheets-Sheet 2 JVENTUJL 5 2521515 TENSE'N :ZTTOENEys Patented Apr. 27, 1937 UNETED STATES PATENT QFFEQE SAND AND MUD SEPARATOR AND MIXER FOR WELL DRILLING sen Application April 13,

3 Claims.

My invention relates to a separator and method of operation in separating the sand or gritlike material from the slushing mud, such as used in deep well drilling or boring. In the hydraulic type of well boring, a slushing mud, the mud being sometimes weighted, is forced to the bottom of the hole at the cutting bit and carries the cuttings, which are usually ground to sand of different degrees of thinness, to the top of the well. My invention pertains to a machine and method for separating this sand from the mud so that the mud may be used for subsequent drilling operations.

An object and feature of my present invention is the employment of elongated channels, parts of which have a fiat floor and the discharge parts a common sloping floor through which the mud with the sand may circulate from one channel to another, and in these channels the sand is allowed to settle to the bottom. In my machine and method the sand is scraped from the bottom in such a manner that there is but little agitation of the mud and, hence, a stirring of the sand into the mud again or a stirring which would still hold the sand in suspension. The sand, being heavier than the particles of the mud, separates to the bottom if the flowing mud is not agitated to too great an extent. Therefore, it is necessary to remove the sand from the flat and inclined floor of each channel in such a manner that the mud is not unduly agitated and that the sand scraped along the bottom is not agitated and again mixed with the mud.

To efiect the removal by a scraping action of the sand, I employ endless belt type of scrapers, these having scraping blades which are drawn along the fiat bottom and up the inclined end of each channel.

Another object and feature of my invention is forming a separator in a tank, this tank having longitudinal partitions. The mud flows in the first channel at the end opposite the inclined discharge floor for the sand and may flow into the second channel before reaching the discharge end. There is a reverse flow of the mud through the second channel, and by a lateral opening the mud flows into the third or last channel. This channel has a partition entirely separating it from the second and first channels except for 5 the inlet at the end remote from the inclined floor.

One of the objects and features of the above construction is to employ a Washing spray and a deflecting partition to maintain the washing water separate from the mud, to a certain extent.

1933, Serial No. 665,923

The washing water is discharged on the sand being moved up the inclined discharge floor by the blades of the endless belts, and this water flows underneath the partition, giving a slight circulation counter to that of the flowing mud, and this maintains the mud slightly thinner adjacent the discharge end than at the other portions of the tank.

Another feature of my invention is having the deflecting partitions spaced parallel to the flat and inclined section of the floor and extending from side to side of the tank, and also in having a discharge outlet from the third channel positioned above the horizontal section of this deflecting partition.

Another detailed feature of my invention is the employment of transverse bafiles which extend below the level of the mud in the tank and terminate above the lower run of the endless belt. These partitions do: not extend up the sloping inclined floor part of the tank.

My invention is illustrated in connection with the accompanying drawings, in which:

Fig. 1 is a plan taken in the direction of the arrow I of Fig. 2.

Fig. 2 is a longitudinal section on the line 22 of Fig. 1, in the direction of the arrows.

Fig. 3 is a transverse section on the line 3-3 of Fig. 1 in the direction of the arrows.

Fig. 4 is a transverse section on the line 44 of Fig. 2 in the direction of the arrows.

In my invention I employ a tank I I which has side walls I2 and I3, an end wall I4, and a flat floor I5. At one end there are inclined side walls I5 having a notched construction I? fitting on the corner formed by the top of the side walls I2 and I3 and the end I8 of such walls. In addition, there is a sloping brace I9 secured to the inside of each wall I2 and I3. Crossbeams 26 extend between the braces I9, and along these braces and the crossbeams there is a sloping discharge floor 2I. A short curved section joins the sloping and the flat floor section I5.

A first partition 23 extends from the end I4 longitudinally of the tank and terminates at 24. A second partition 25 is spaced from the end I4 by a flow opening 26 and extends the full length of the tank, terminating at 2?. If this partition should be formed as high as the side walls I2 and I3, or if it is built of lesser height, it may terminate short of the end I8 of the tank, and its end 21 conforms to the sloping floor 2|. Cross boards 28 and 29 extend across all of the partitions between the sides I2 and I3.

A deflecting partition designated by the assembly numeral 30' has a flat section 3| parallel to the fiat floor I5 and a sloping section 32 which is spaced from the sloping discharge floor 2| but need not be parallel thereto. On account of the partition 25 extending up the sloping floor 2|, the deflecting partition is formed in one part with the edges fitting in grooves 33 in the partition 25 and the side wall I3. (Note Fig. 3.) The other section of the deflecting partition extends from the partition 25 to the wall I2 and has a notched-out section 34 at the end 24 of the partition 23. This deflecting partition terminates at its upper edge at 35 and at its lower edge at 36.

A spray pipe 31 extends across the-tank between the walls I2 and I3 and above the partition 25. This may be connected to a source of water supply and has spray jets 38 discharging downwardly on the sloping discharge floor 3| above the upper end 35 of the deflecting partition 33. The purpose of this is described hereinunder.

The endless belt or conveyor system utilizes a main drive shaft 39 which is journaled in the side walls I2 and I3 and has a water tight packing therein. An idler shaft 40 is located adjacent the end I4 and a second idler shaft 4| adjacent the upper end of the inclined discharge floor structure. The shaft 40 is journaled in the opposite sides I2 and I3 of the tank and the shaft in the sloping sides I6. These shafts are all provided with sprocket wheels 42. There are three of these sprocket wheels on each shaft. A first sprocket chain 43 operates in the channel 44 formed between the wall I2 and the partition 23; a second chain 45 operates in the second channel 46 between the partitions 23 and 25; a third chain 41 operates in the channel 48 between the partition 25 and the side wall I3. Each of these conveyor chains has a series of scraper blades 49, these blades being arranged so that on the lower run of each conveyor chain they scrape the sand along the fiat floor I5 of each channel toward the inclined floor and upwardly along the inclined floor 2| to discharge at the discharge end 50 of the machine. The distance between the blades 49 is released for the first chain 43 operating in the first channel 44; the spacing is greatest on the chain 41 operating in the third channel 48; the spacing intermediate in the center channel. The purpose of this spacing is hereinunder detailed.

An electric motor 5| is indicated as having a drive connection 52 operating the power shaft 39 and, hence, by means of the sprockets 42 conveying motion to the main shaft 39 and moving all of the conveyors at the same speed.

The slushing mud is fed into the tank through an inlet pipe 53 or the like at the end of the first channel 44 adjacent the wall I 4. The flow of the slushing mud is gradually along this channel in the direction of the arrow 54. There is then a reverse flow in the direction of the arrow 55 from the end 24 of the partition 23. The reverse fiow continues in the direction of the arrow 55 in the second channel 46. There is another reverse flow indicated by the arrow 51 through the flow passage 26 and then longitudinally in the direction of the arrow 58 in the third channel 48 to a discharge trough 59. This trough fits in an opening Gil in the side wall I3.

A series of baflle plates 6| extend'between the outside Walls and the partitions and for the channel 46 between the two partitions. On account of the endless chains each forming a triangular path, some of these bafile plates, such'as 62, must be of decreased height to allow the lower run of the endless chains to pass over. Therefore, should the level of the slushing mud be raised to increase the flow, certain of the bafiles may be completely immersed but the major number of the bailles extend above the liquid level of the mud. Therefore, the mud must flow downwardly on the face of each baflle and underneath. This gives a downward movement to any sand held in suspension in the mud and tends to aid the separation of the sand and the mud, the sand being deposited by gravity on the fiat bottom floor I5 and a portion, possibly, on the inclined fioor 2|.

The method of operation and functioning of my invention is substantially as follows:

On account of a continuous infeed of mud with the sand incorporated therein at 53 at the intake end of the first channel 44, the mud must fiow slowly longitudinally of this first channel, the fiow being interrupted by the bafiles. During this flow the scraper blades on the first chain d3 have their under run moving in the direction of the fiow of the mud. I find it desirable to have the speed of the belts quite slow and not more than about three feet per second. This appears to avoid undue stirring of the sand deposited again into the mud and also a stirring action of the mud which will still hold the sand in suspension. In the first channel, on account of the mud and the endless conveyor of blades moving in the same direction, there is but little agitation of the sand and mud. Hence, the sand deposited on the fiat fioor is readily scraped longitudinally of this floor and upwardly of the sloping or inclined fioor 2|, the sand being discharged.

over the end 50. This sand is found to be usually of coarsest grain and heaviest. In the reverse flow channel 56 the fiow of the mud is in a counterdirection to that of the scraping blades in the lower run of the endless chain 45. Even in this case the flow of the mud as a whole is so comparatively slow that there is but little agitation of the sand and mud and this second conveyor removes sand of an intermediate degree of fineness. In the third channel 48 the direction of movement of the flowing mud and the endless conveyor chain is in the same direction.

The function of the sprayer jets through the spray pipe 31 is to flow clear water on the sand being conveyed up the inclined floor 2|. This spray removes mud which might be adherent to the sand and thus cleans the sand so that gritty matter is deposited at the discharge end 53. The sand discharged at the end of the channel 48 is usually the thinnest.

In addition, the water flowing downwardly on the inclined fioor 2| flows between a space confined by this floor and the sloping portion 32 of the deflecting partition and the side wall I3 and the partition 25 for the third channel 48. Between the partition 25 and the side Wall I2 there is no partition separating the space between the inclined deflecting partition and the sloping fioor 2|. On account of the discharge trough 53 being located above the horizontal portion 3| and the deflecting partition and spaced toward the discharge end of the machine from the edge 36 of this partition, the slushing mud does not tend to flow between the partition and the floor I 5 but the spray jets in supplying a quantity of water adjacent the end 35 of the deflecting plate cause a thinning out of the mud at this end of the machine and, if anything, tend to form a reverse flow of the diluted mud toward the edge 36 of the deflecting plate. Therefore, as the bladesof the endless conveyors pass underneath the section 3| of the deflecting plate, the mud becomes somewhat thinner and thereby forms a more complete separation of the sand and mud and allows a more ready depositing by gravity of the sand in the diluted mud. On the lower part of the sloping floor 2| the mud is diluted to its greatest extent and this prevents the sand being scraped up from the sloping discharge floor from being stirred up again in the mud, as well as facilitates depositing of the sand. Moreover, as above mentioned, the slow movement of the blades of the conveyor is such that they do not tend to stir the sand deposited again into the mud or maintain the mud agitated to such an extent that the sand cannot be deposited by gravity.

In constructing the tank and channels, it is desirable to have a floor surface both on the fiat bottom 15 and on the inclined end with a smooth finish so that the sand may readily be scraped along the bottom and up the inclined end to the discharge part of this end above the mud level. Also, it is preferable to form the deflecting partition 30 of a comparatively thin metal plate, thus forming a deflecting plate so that this may be positioned quite close to the lower run of the conveyor. Substantially all parts of the channels and tank are scraped by the blades of the endless conveyors except the upper surface of the deflecting plate. The horizontal part of this plate between the first channel 44 and the second channel 46 is at the place of reverse flow 55 of the mud and, hence, but little sand is deposited on this horizontal portion of the deflecting plate.

The outlet for desanded mud is positioned above the horizontal position of the deflecting plate, but at this position the mud is Well desanded so but little sand can be deposited on this portion of the plate in the last or third channel 48.

In connection with my method of operation, this consists in part in using a scraping action for removing the deposited sand, the scraping action being in two of the channels in the direction of the flow of the mud and in the center channel in a direction reverse to the flow of the mud.

Another feature is that the endless chains or belts on which the scraping blades are mounted, together with the blades, have but little stirring action when drawn through the mud and deposited sand, due partly to the low rate of speed and partly to the construction of the endless conveyors. Therefore, the sand already deposited is not stirred into the mud and the mud is not agitated to enable it to hold the sand in suspension.

Another feature of the method operation comprises the injection of water on the sand being scraped up the inclined end and the dilution of the mud between the end and the floor of the channels adjacent this inclined end so that any sand held in the mud at the ends of the channels adjacent the inclined end settles more readily than it would through thicker or undiluted mud.

An important characteristic of my invention is that the sand in being conveyed up the inclined discharge end is carried through a passage in which the mud is diluted by the spray of injected water 38. Thus the mud in this passage cannot sustain the sand as well as the thicker mud and causes the mud to allow the settlement of the sand more readily. Also, the mud which would tend to cling to the sand is Washed from this sand and such mud is thereby saved.

My sand and mud separator functions in operation to a certain extent as a classifier in regard to the degree of coarseness or size of the sand. As the sand and mud enters the tank at 53, it flows in the first channel in the direction of the arrow 54 and in this channel the coarse or heaviest sand is deposited, this being scraped out at the discharge end for the sand. In the middle channel the sand and mud flow in a reverse direction and sand of an intermediate size is deposited, which is scraped out by itself. In the third or final channel the sand and mud flows in the direction of the scrapers and here the lightest or finest sand is deposited, this being removed by a separate scraper.

In the flow of the sand and mud in the various channels, the baffles 6| deflect the flow downwardly, forcing the sand and mud in a downward and in an upward direction at each bafile. This develops a centrifugal action on the sand, causing the heavier particles to be discharged downwardly on to the floor I5, where they may be engaged by the scrapers.

The horizontal section 3| of the partition 30 functions somewhat as a skimmer, especially in the last channel of flow. This horizontal partition forms a positive dividing line between the mud at the surface and the sand being scraped through a portion of the mud longitudinally on the floor l and up the inclined fioor 2| of the last channel. The mud thus skimmed from the surface is discharged at 59 located substantially transverse to the horizontal section 3| of the partition. Therefore the mud being skimmed off at this last channel is maintained quite separate and distinct from the mud and sand in the lower part of the channel.

The water spray 38 functions to wash the mud from the sand conveyed upwardly on the inclined floor 2!. It also to a certain extent dilutes the mud in the space between the cross partition 30, the floor l5 and the inclined floor 2 l On account of diluting the mud in this space, the sand more readily separates from such diluted mud than from the concentrated mud. Although in the discharge channel the general flow of the sand and mud is towards the discharge trough 59, the water spray 38 in flowing water underneath the partition 30 gives a slight counter-current in the space below the partition 30, thus tending to more thoroughly separate the sand and mud at the last channel before the sand is conveyed upwardly on the inclined floor 2|.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. In a device as described, an elongated tank having a flat floor and an inclined discharge end, means forming an inlet for mud containing sand at the end remote from the discharge end, a plurality of bafile plates positioned in the tank to extend above the level of liquid therein, the lower ends of the baflles being spaced above the bottom of the tank, whereby sand conveying mud flowing longitudinally of the tank is forced downwardly under each baffle to facilitate separating sand from the mud, a conveyor operating along the floor of the tank and upwardly on the discharge end to remove sand deposited in the tank, and means to discharge desanded mud adjacent the inclined discharge end of the tank.

- 2. In a device as claimed in claim 1, the means to discharge the desanded mud including a horizontal partition in the tank forming a skimming device, said partition being located below the liq- 5 uid level of the tank, the tank having an overflow with a bottom edge located at or below the said partition.

3. In a device as described, the combination of an elongated tank having a flat floor and an inlo clined end for the discharge of sand, a series of transverse baflie plates positioned in the tank, the upper edgesbeing adapted to be positioned above the level of liquid in the tank and the lower edges spaced above the floor of the tank, a horizontal l5 partition adjacent the discharge end of the tank having a horizontal section above the floor and a sloping section above the inclined end of the tank,

said partition with the bottom, sides and inclined end of the tank forming a channel for liquid, said partition forming a skimming device, means forming an inflow for mud containing sand at the end of the tank remote from the inclined end, a conveyor operating along the bottom and up the inclined end of the tank for removal of sand, the said baflles causing a downward and an upward flow of the mud containing sand to facilitate separation of sand from the mud,. the tank having an overflow for desanded mud having its bottom edge located at or above the horizontal section of the partition of the skimming device.

CHRIS T. CHRISTENSEN.

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