CA1037778A - Displacement slurry pump - Google Patents
Displacement slurry pumpInfo
- Publication number
- CA1037778A CA1037778A CA241,106A CA241106A CA1037778A CA 1037778 A CA1037778 A CA 1037778A CA 241106 A CA241106 A CA 241106A CA 1037778 A CA1037778 A CA 1037778A
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- section
- auxiliary liquid
- piston
- piston rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Details Of Reciprocating Pumps (AREA)
- Reciprocating Pumps (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a displacement slurry pump comprising a cylinder having, in coaxial arrangement, a slurry section and an auxiliary liquid section with a diameter greater than that of said slurry section, a reciprocable piston rod in said cylinder carrying a slurry piston in the slurry section with a diameter such that an aperture remains between the periphery of the piston and the wall of the slurry section, and an auxiliary liquid piston with a diameter providing a sealed fitting in the auxiliary liquid section of said cylinder, said slurry piston and said auxiliary liquid piston being separated on said piston rod by at least one stroke length, said slurry section being closed at its end farthest from said auxiliary liquid section and provided adjacent said end with valved slurry inlet means and valved slurry outlet means, said auxiliary liquid section being provided adjacent the slurry section with valved means for introducing auxiliary liquid at a pressure greater than the pressure, at said slurry inlet means, said slurry section being closed at its end farthest from said piston rod passing through packing gland means in said closed end of said slurry section, flange means attached to the inner wall of said closed end of said slurry section, thereby forming an auxiliary liquid compartment in said slurry section, said flange means being provided with an aperture larger than the cross-section of said piston rod through which said piston rod passes relatively loosely, and external valved duct means connecting said auxiliary liquid compartment with said auxiliary liquid section at a locus adjacent the slurry section.
The present invention provides a displacement slurry pump comprising a cylinder having, in coaxial arrangement, a slurry section and an auxiliary liquid section with a diameter greater than that of said slurry section, a reciprocable piston rod in said cylinder carrying a slurry piston in the slurry section with a diameter such that an aperture remains between the periphery of the piston and the wall of the slurry section, and an auxiliary liquid piston with a diameter providing a sealed fitting in the auxiliary liquid section of said cylinder, said slurry piston and said auxiliary liquid piston being separated on said piston rod by at least one stroke length, said slurry section being closed at its end farthest from said auxiliary liquid section and provided adjacent said end with valved slurry inlet means and valved slurry outlet means, said auxiliary liquid section being provided adjacent the slurry section with valved means for introducing auxiliary liquid at a pressure greater than the pressure, at said slurry inlet means, said slurry section being closed at its end farthest from said piston rod passing through packing gland means in said closed end of said slurry section, flange means attached to the inner wall of said closed end of said slurry section, thereby forming an auxiliary liquid compartment in said slurry section, said flange means being provided with an aperture larger than the cross-section of said piston rod through which said piston rod passes relatively loosely, and external valved duct means connecting said auxiliary liquid compartment with said auxiliary liquid section at a locus adjacent the slurry section.
Description
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The present invention relates to a displacement slurry pump equipped with a piston-rod drive, or which on a piston rod two and preferably three pistons are mounted at a distance of at least one stroke lenqth. The pistons include a liquid piston moving a auxiliary liquid free of solid matter, and on at least one and preferably both sides thereof a slurry piston each moving on one side thereof the slurry, and on the other side, the auxiliary liquid. The liquid piston sealingly fits to the liquid cylinder provided with liquid suction valves, whereas the each slurry piston fits with an aperture to the slurry cylinders provided with slurry suction valves and slurry delivery valves. The effective section of the liquid cylinder is larger than the effective section of each slurry cylinder. The slurry pump may be of single-operation or of double-operation, of one-cylinder or two-cylinder or three-cylinder construction. During the operation, on the delivery stroke of the slurry cylinder, auxiliary liquid is forced from the liquid cylinder through the aperture between the slurry cylinder and slurry piston, thus preventing the slurry from flowing in between the slurry piston -~ 20 and the slurry cylinder. Thus the lift of the slurry pistons ; increases the pump filled application in the fields of: alumina ' production, mining industry, mineral oil industry and thermal --power stations.
The delivery in medium- and high-pressure range of slurries of high solids content and erosion properties causes a considerable problem all over the world, especially in the chemical industry, alumina production and mining industry. The pump elements rubbing against each other during the operation and also contacting the slurry are subjected to considerable wear, and thus their operational life is short. The present invention _ provides a slurry pump in which the frictional pump elements cannot contact the slurry and thus, their lift is increased.
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With conventional displacement slurry pumps the slurry directly contacts the piston, the inner surface of the cylinder, the piston rod and the packing material of the packing gland of the piston rod. All these parts must be replaced after a shorter or longer period which is an expensive and labour -~ intensive operation. Further, in continuous operation an emergency pump must be kept available.
These disadvantages are eliminated by the well known diaphragm pumps used for the delivery of high~pressure slurries, which, however, are extremely expensive and also the life of the diaphragm is limited.
Recently the pressure-vessel slurry pumps (hydro hoist) ; have appeared, the operation of which is briefly as follows.
The low-pressure pump presses the slurry into, for example, the lower part of the first unit of three pressure vessels connected in parallel. The slurry level having reached a specified value, the low-pressure slurry pressure duct automatically changes over to the following unit, while the high-pressure auxiliary - liquid pump beings to force auxiliary liquid into the upper part of the first unit. This auxiliary liquid then forces the slurry out a-t a hiyh pressure from the lower part of the unit. When i~ the second pressure vessel is also filled with low-pressure slurry, the high-pressure auxiliary liquid is connected thereto, while the low-pressure slurry pressure duct is connected to the , third pressure vessel. This process is cyclically repeated so that in this way the delivery of the slurry at high pressure is continuously obtained. For the practical application of this principle there are several partial solutions. The slurry in -~ the pressure vessel is, for example, separated by a disc operating like a piston from the auxiliary liquid located above . it. However there is also a solution, where the two liquids are in direct contact. In this case, however, the auxiliary
The present invention relates to a displacement slurry pump equipped with a piston-rod drive, or which on a piston rod two and preferably three pistons are mounted at a distance of at least one stroke lenqth. The pistons include a liquid piston moving a auxiliary liquid free of solid matter, and on at least one and preferably both sides thereof a slurry piston each moving on one side thereof the slurry, and on the other side, the auxiliary liquid. The liquid piston sealingly fits to the liquid cylinder provided with liquid suction valves, whereas the each slurry piston fits with an aperture to the slurry cylinders provided with slurry suction valves and slurry delivery valves. The effective section of the liquid cylinder is larger than the effective section of each slurry cylinder. The slurry pump may be of single-operation or of double-operation, of one-cylinder or two-cylinder or three-cylinder construction. During the operation, on the delivery stroke of the slurry cylinder, auxiliary liquid is forced from the liquid cylinder through the aperture between the slurry cylinder and slurry piston, thus preventing the slurry from flowing in between the slurry piston -~ 20 and the slurry cylinder. Thus the lift of the slurry pistons ; increases the pump filled application in the fields of: alumina ' production, mining industry, mineral oil industry and thermal --power stations.
The delivery in medium- and high-pressure range of slurries of high solids content and erosion properties causes a considerable problem all over the world, especially in the chemical industry, alumina production and mining industry. The pump elements rubbing against each other during the operation and also contacting the slurry are subjected to considerable wear, and thus their operational life is short. The present invention _ provides a slurry pump in which the frictional pump elements cannot contact the slurry and thus, their lift is increased.
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With conventional displacement slurry pumps the slurry directly contacts the piston, the inner surface of the cylinder, the piston rod and the packing material of the packing gland of the piston rod. All these parts must be replaced after a shorter or longer period which is an expensive and labour -~ intensive operation. Further, in continuous operation an emergency pump must be kept available.
These disadvantages are eliminated by the well known diaphragm pumps used for the delivery of high~pressure slurries, which, however, are extremely expensive and also the life of the diaphragm is limited.
Recently the pressure-vessel slurry pumps (hydro hoist) ; have appeared, the operation of which is briefly as follows.
The low-pressure pump presses the slurry into, for example, the lower part of the first unit of three pressure vessels connected in parallel. The slurry level having reached a specified value, the low-pressure slurry pressure duct automatically changes over to the following unit, while the high-pressure auxiliary - liquid pump beings to force auxiliary liquid into the upper part of the first unit. This auxiliary liquid then forces the slurry out a-t a hiyh pressure from the lower part of the unit. When i~ the second pressure vessel is also filled with low-pressure slurry, the high-pressure auxiliary liquid is connected thereto, while the low-pressure slurry pressure duct is connected to the , third pressure vessel. This process is cyclically repeated so that in this way the delivery of the slurry at high pressure is continuously obtained. For the practical application of this principle there are several partial solutions. The slurry in -~ the pressure vessel is, for example, separated by a disc operating like a piston from the auxiliary liquid located above . it. However there is also a solution, where the two liquids are in direct contact. In this case, however, the auxiliary
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liquid is generally oil. This can be, however, used only in case of a technology where a part of the oil entering into the slurry does not cause any trouble. The pressure-vessel slurry pumps are provided with highly intricate automatic equipment for ensuring the alternating opening and closing of the valves.
The present invention is a development of the dis-placement pump such that no slurry can contact the slidiny parts and, only an auxiliary liquid free of solids can directly contact these parts. The auxiliary liquid is selected not to have an erosive action, and on the other hand a few per cent such that it thereof enters the slurry, this would be useful or of no effect. Such an auxiliary liquid could be water in case of fly ash or mining sludge, and digesting liquor for a slurry in alumina production.
According to the present invention therefore there is provided a displacement slurry pump comprising a cylinder having, in coaxial arrangement, a slurry section and an auxiliary liquid section with a diameter greater than that of said slurry section, a reciprocable piston rod in said cylinder carrying a ~ ;
slurry piston in the slurry section with a diameter such that an aperture remains between the periphery of the piston and the wall of the slurry section, and an auxiliary liquid piston with a diameter providing a sealed fitting in the auxiliary liquid section of said cylinder, said slurry piston and said auxiliary liquid piston being separated on said piston rod by at least one ; stroke length, said slurry section being closed at its end farthest from said auxiliary liquid section and provided adjacent said end with valved slurry inlet means and valved slurry outlet means, said auxiliary liquid section being provided adjacent ; 30 the slurry section with valved means for introducing auxiliary liquid at a pressure greater than the pressure, at said slurry inlet means, said slurry section being closed at its end farthest _ 3 _ .
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-` lQ37~8 from said piston rod passing throuyh packing gland means in said closed end of said slurry section, flange means attached - to the inner wall of said closed end of said slurry section, thereby forming an auxiliary liquid compartment in said slurry section, said flange means being provided with an aperture larger than the cross-section of said piston rod through which said piston rod passes relatively loosely, and external valved duct means connecting said auxiliary liquid compartment with said auxiliary liquid section at a locus adjacent the slurry section.
Thus in accordance with the present invention the - displacement slurry pump is equipped with a piston-rod drive which has a slurry cylinder and a liquid cylinder with a common shaft, directly connected to each other. The diameter of said liquid cylinder is larger than that of said slurry cylinder and in said slurry cylinder a slurry piston is fitted with an aperture. In said liquid cylinder, however, a liquid piston is sealingly fitted. The slurry piston and the liquid piston are arranged on a common piston rod in a distance from each - 20 other of at least one stroke length. The liquid cylinder has in its dead space towards said slurry cylinder a liquid inlet valve connected to an auxiliary liquid duct. The slurry cylinder has in its dead space farther from said liquid cylinder a slurry suction valve connected to a slurry suction duct and slurry delovery valve connected to a slurry delivery duct. In - an advantageous embodiment, on a piston rod slurry pistons are arranged on each side of the liquid piston and a corresponding cylinder for said liquid piston as well as for the pair of slurry pistons. The slurry pump according to the invention can be in duplicate, triplicate, or any other construction. Each embodi-~ ment can be produced in such a way on the side towards the slurry - of a packing gland of piston rod a protective cone fitted by ;:
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slot to said piston rod is fastened to the cylinder bottom.
The space under said protective cone is connected to the pressure chamber of said liquid cylinder by a channel or a duct and in the channel or duct a pressure valve opening to said slurry cylinder is located, making possible due to the pressure of the auxiliary liquid that such auxiliary liquid enters the inside ;~
of said protective cone and therefrom a part of the auxiliary liquid enters the slurry space through the slot between said ;~ protective cone and said piston rod, respectively.
The present invention will be further illustrated by way of the accompanying drawings in which:
Figure 1 is a schematic of one-cylinder, single-acting slurry pump according to one embodiment of the present ; invention, -Figure 2 is a schematic of the one-cylinder double-acting slurry pump according to a further embodiment of the present invention, ~ Figure 3 is a schematic of a double-cylinder (duplex) .~ embodiment slurry pump according to a further embodiment of ; 20 the present invention, ' In Yigure 1 a slurry cylinder 2 is connected to a~; liquid cylinder 1 of large cylinder bore. A liquid piston 4 and a slurry piston 5 of smaller effective section, are located on a common piston rod 3 at a distance greater than one stroke.
Between the slurry piston S and the inner surface of the slurry cylinder 2 an annular slot (aperture) 18 is provided. A liquid ` suction valve 6 is connected to the liquid cylinder 1, and to the slurry cylinder 2 and a slurry suction valve 7 and a slurry delivery valve 8 are connected. The piston rod 3 extends through the cylinder head 9 of the slurry cylinder 2, where sealing is provided by a packing gland 10. To the inside of the cylinder head 9 a protective cone 11 is fixedly joined by its flange, in '' ' , ', ~ ~ 5 -,: ~
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1~3~7778 which an aperture 12 is present for the passage of the piston rod 3, this aperture 12 being larger than the cross-section of ': the piston rod 3. Consequently an annular slot (aperture) 17 : is present between the piston rod 3 and the protective cone 11.
An opening 13 is present on the cylinder head 9 which is connect-ed through a duct 14 to an opening 15 on the liquid cylinder 1.
The duct 14 is provided with a pressure valve 16.
The operation of the single cylinder, single-actir.g slurry pump is as follows: It is started from the condition .. 10 where the cylinder space between the liquid piston 4 and the slurry piston 5 is filled with auxiliary liquid. On the suction stroke slurry flows through the slurry suction valve 7 in the ~ cylinder space towards the slurry delivery valve 8 of the slurry : cylinder 2. In the meantime, an auxiliary liquid supply enters through the liquid suction valve 6 into the cylinder space :
between the liquid piston 4 and the slurry piston 5. The quantity per stroke of this supply is substantial].y equal to : the product of the difference of effective sections of liquid piston 4 and slurry piston 5 and of the stroke, assuming that the pressure of the auxiliary liquid flowing in at the liquid . suction valve 6 is higher than that of the slurry flowing in at the slurry suction valve 7. On the delivery stroke, the slurry ~.
discharged through the slurry delivery valve 8, and at the same time, the quantity of auxiliary liquid sucked in as feed during .
the suction stroke is on the one hand forced through the slot 18 at the periphery of the slurry piston 5 into the cylinder :~
space towards the slurry inlet valve 7 of the slurry cylinder . 2, and on the other hand, through the opening 15, duct 14, opening 13 and the pressure valve 16 into the space under the protective cone 11, and therefrom through the aperture 17 to the cylinder space towards the slurry suction valve 7 of the slurry cylinder 2. During the delivery stroke the auxiliary .
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liquid flowing through the aperture 18 prevents the slurry from entering in between the slurry piston 5 and the internal surface of the slurry cylinder 2, whereas the auxiliary liquid flowing through the aperture 17 prevents the slurry from entering under the protective cone ll, and to the packing gland 10, respective-ly. Under such conditions the slurry cylinder 2, the slurry piston 5, the piston rod 3 and the packing gland 10 are prote~te against the erosion effects of the slurry.
The slurry pump shown in Figure 2 is double acting.
Its left side is identical with the slurry pump shown in Figure l, whereas its right side is the symmetrical equivalent thereof.
On a piston rod 3a three pistons, namely a slurry piston 5, a liquid piston 4 and a second slurry piston 5a are mounted. With respect to the pistons and to the corresponding cylinders, only the liquid piston 4 is double acting, since at each stroke it sucks the auxiliary liquid on the one side and discharges it on the other side. The slurry piston 5 sucks the slurry at the stroke towards the pump centre, and forces it out at the stroke in the opposite direction. The slurry piston 5a forces the slurry out at the stroke towards the pump centre, and sucks it in at the stroke in opposite direction. It is well known that the double-acting construction delivers the slurry more uni-formly, than the single-acting one, illustrated in Figure l.
Figure 3 shows a two-cylinder duplex double-acting embodiment of the slurry pump accordin~3 to the invention. In this case, by the expression "duplex" two cylinder rows arranged parallel to each other and each comprising three cylinders, namely la, 2, 2a re to be understood. The crank arms of the two . ~, .
piston rods 3a are wedged at 90~ to each other as usual with the -duplex pumps, that is, if one piston row is, for example, in the end position, the other one is in mid-position. In Figure
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liquid is generally oil. This can be, however, used only in case of a technology where a part of the oil entering into the slurry does not cause any trouble. The pressure-vessel slurry pumps are provided with highly intricate automatic equipment for ensuring the alternating opening and closing of the valves.
The present invention is a development of the dis-placement pump such that no slurry can contact the slidiny parts and, only an auxiliary liquid free of solids can directly contact these parts. The auxiliary liquid is selected not to have an erosive action, and on the other hand a few per cent such that it thereof enters the slurry, this would be useful or of no effect. Such an auxiliary liquid could be water in case of fly ash or mining sludge, and digesting liquor for a slurry in alumina production.
According to the present invention therefore there is provided a displacement slurry pump comprising a cylinder having, in coaxial arrangement, a slurry section and an auxiliary liquid section with a diameter greater than that of said slurry section, a reciprocable piston rod in said cylinder carrying a ~ ;
slurry piston in the slurry section with a diameter such that an aperture remains between the periphery of the piston and the wall of the slurry section, and an auxiliary liquid piston with a diameter providing a sealed fitting in the auxiliary liquid section of said cylinder, said slurry piston and said auxiliary liquid piston being separated on said piston rod by at least one ; stroke length, said slurry section being closed at its end farthest from said auxiliary liquid section and provided adjacent said end with valved slurry inlet means and valved slurry outlet means, said auxiliary liquid section being provided adjacent ; 30 the slurry section with valved means for introducing auxiliary liquid at a pressure greater than the pressure, at said slurry inlet means, said slurry section being closed at its end farthest _ 3 _ .
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-` lQ37~8 from said piston rod passing throuyh packing gland means in said closed end of said slurry section, flange means attached - to the inner wall of said closed end of said slurry section, thereby forming an auxiliary liquid compartment in said slurry section, said flange means being provided with an aperture larger than the cross-section of said piston rod through which said piston rod passes relatively loosely, and external valved duct means connecting said auxiliary liquid compartment with said auxiliary liquid section at a locus adjacent the slurry section.
Thus in accordance with the present invention the - displacement slurry pump is equipped with a piston-rod drive which has a slurry cylinder and a liquid cylinder with a common shaft, directly connected to each other. The diameter of said liquid cylinder is larger than that of said slurry cylinder and in said slurry cylinder a slurry piston is fitted with an aperture. In said liquid cylinder, however, a liquid piston is sealingly fitted. The slurry piston and the liquid piston are arranged on a common piston rod in a distance from each - 20 other of at least one stroke length. The liquid cylinder has in its dead space towards said slurry cylinder a liquid inlet valve connected to an auxiliary liquid duct. The slurry cylinder has in its dead space farther from said liquid cylinder a slurry suction valve connected to a slurry suction duct and slurry delovery valve connected to a slurry delivery duct. In - an advantageous embodiment, on a piston rod slurry pistons are arranged on each side of the liquid piston and a corresponding cylinder for said liquid piston as well as for the pair of slurry pistons. The slurry pump according to the invention can be in duplicate, triplicate, or any other construction. Each embodi-~ ment can be produced in such a way on the side towards the slurry - of a packing gland of piston rod a protective cone fitted by ;:
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slot to said piston rod is fastened to the cylinder bottom.
The space under said protective cone is connected to the pressure chamber of said liquid cylinder by a channel or a duct and in the channel or duct a pressure valve opening to said slurry cylinder is located, making possible due to the pressure of the auxiliary liquid that such auxiliary liquid enters the inside ;~
of said protective cone and therefrom a part of the auxiliary liquid enters the slurry space through the slot between said ;~ protective cone and said piston rod, respectively.
The present invention will be further illustrated by way of the accompanying drawings in which:
Figure 1 is a schematic of one-cylinder, single-acting slurry pump according to one embodiment of the present ; invention, -Figure 2 is a schematic of the one-cylinder double-acting slurry pump according to a further embodiment of the present invention, ~ Figure 3 is a schematic of a double-cylinder (duplex) .~ embodiment slurry pump according to a further embodiment of ; 20 the present invention, ' In Yigure 1 a slurry cylinder 2 is connected to a~; liquid cylinder 1 of large cylinder bore. A liquid piston 4 and a slurry piston 5 of smaller effective section, are located on a common piston rod 3 at a distance greater than one stroke.
Between the slurry piston S and the inner surface of the slurry cylinder 2 an annular slot (aperture) 18 is provided. A liquid ` suction valve 6 is connected to the liquid cylinder 1, and to the slurry cylinder 2 and a slurry suction valve 7 and a slurry delivery valve 8 are connected. The piston rod 3 extends through the cylinder head 9 of the slurry cylinder 2, where sealing is provided by a packing gland 10. To the inside of the cylinder head 9 a protective cone 11 is fixedly joined by its flange, in '' ' , ', ~ ~ 5 -,: ~
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1~3~7778 which an aperture 12 is present for the passage of the piston rod 3, this aperture 12 being larger than the cross-section of ': the piston rod 3. Consequently an annular slot (aperture) 17 : is present between the piston rod 3 and the protective cone 11.
An opening 13 is present on the cylinder head 9 which is connect-ed through a duct 14 to an opening 15 on the liquid cylinder 1.
The duct 14 is provided with a pressure valve 16.
The operation of the single cylinder, single-actir.g slurry pump is as follows: It is started from the condition .. 10 where the cylinder space between the liquid piston 4 and the slurry piston 5 is filled with auxiliary liquid. On the suction stroke slurry flows through the slurry suction valve 7 in the ~ cylinder space towards the slurry delivery valve 8 of the slurry : cylinder 2. In the meantime, an auxiliary liquid supply enters through the liquid suction valve 6 into the cylinder space :
between the liquid piston 4 and the slurry piston 5. The quantity per stroke of this supply is substantial].y equal to : the product of the difference of effective sections of liquid piston 4 and slurry piston 5 and of the stroke, assuming that the pressure of the auxiliary liquid flowing in at the liquid . suction valve 6 is higher than that of the slurry flowing in at the slurry suction valve 7. On the delivery stroke, the slurry ~.
discharged through the slurry delivery valve 8, and at the same time, the quantity of auxiliary liquid sucked in as feed during .
the suction stroke is on the one hand forced through the slot 18 at the periphery of the slurry piston 5 into the cylinder :~
space towards the slurry inlet valve 7 of the slurry cylinder . 2, and on the other hand, through the opening 15, duct 14, opening 13 and the pressure valve 16 into the space under the protective cone 11, and therefrom through the aperture 17 to the cylinder space towards the slurry suction valve 7 of the slurry cylinder 2. During the delivery stroke the auxiliary .
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liquid flowing through the aperture 18 prevents the slurry from entering in between the slurry piston 5 and the internal surface of the slurry cylinder 2, whereas the auxiliary liquid flowing through the aperture 17 prevents the slurry from entering under the protective cone ll, and to the packing gland 10, respective-ly. Under such conditions the slurry cylinder 2, the slurry piston 5, the piston rod 3 and the packing gland 10 are prote~te against the erosion effects of the slurry.
The slurry pump shown in Figure 2 is double acting.
Its left side is identical with the slurry pump shown in Figure l, whereas its right side is the symmetrical equivalent thereof.
On a piston rod 3a three pistons, namely a slurry piston 5, a liquid piston 4 and a second slurry piston 5a are mounted. With respect to the pistons and to the corresponding cylinders, only the liquid piston 4 is double acting, since at each stroke it sucks the auxiliary liquid on the one side and discharges it on the other side. The slurry piston 5 sucks the slurry at the stroke towards the pump centre, and forces it out at the stroke in the opposite direction. The slurry piston 5a forces the slurry out at the stroke towards the pump centre, and sucks it in at the stroke in opposite direction. It is well known that the double-acting construction delivers the slurry more uni-formly, than the single-acting one, illustrated in Figure l.
Figure 3 shows a two-cylinder duplex double-acting embodiment of the slurry pump accordin~3 to the invention. In this case, by the expression "duplex" two cylinder rows arranged parallel to each other and each comprising three cylinders, namely la, 2, 2a re to be understood. The crank arms of the two . ~, .
piston rods 3a are wedged at 90~ to each other as usual with the -duplex pumps, that is, if one piston row is, for example, in the end position, the other one is in mid-position. In Figure
3, in order to make the Figure more clear, the duct 14 and its ,~
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accessories are not shown.
The slurry pump according to Figures 2 and 3 operates in such a manner that on both sides of the liquid piston 4 auxiliary liquid free of solid is present. The slurry flows in at the corresponding suction stroke through the slurry suction valve 7 (7a) into the cylinder space between the slurry piston 5 (5a) and the cylinder head 9 (9a). In the course of the operation, the auxiliary liquid flows through the apertures 18 (18a) and 17 (17a) on the delivery stroke of the slurry piston 5 (5a) thus preventing that the slurry gettina between the slurry piston 5 (5a) and the cylinder 2 (2a) as well as in between the piston rod 3a and the packing gland 10 (lOa). The apertures 17 (17a) and 18 (18a) as well as the pressure valve 16 are dimensioned so that only a minimum quantity of auxiliary liquid could get into the slurry and at the same time. No slurry can get in between the surfaces sliding on each other.
The slurry pump according to the invention can be advantageously used in the alumina production, in the mineral oil and mining industry and anywhere slurry of high volume-speed -.
~ 20 is to be delivered at a high pressure. ~
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accessories are not shown.
The slurry pump according to Figures 2 and 3 operates in such a manner that on both sides of the liquid piston 4 auxiliary liquid free of solid is present. The slurry flows in at the corresponding suction stroke through the slurry suction valve 7 (7a) into the cylinder space between the slurry piston 5 (5a) and the cylinder head 9 (9a). In the course of the operation, the auxiliary liquid flows through the apertures 18 (18a) and 17 (17a) on the delivery stroke of the slurry piston 5 (5a) thus preventing that the slurry gettina between the slurry piston 5 (5a) and the cylinder 2 (2a) as well as in between the piston rod 3a and the packing gland 10 (lOa). The apertures 17 (17a) and 18 (18a) as well as the pressure valve 16 are dimensioned so that only a minimum quantity of auxiliary liquid could get into the slurry and at the same time. No slurry can get in between the surfaces sliding on each other.
The slurry pump according to the invention can be advantageously used in the alumina production, in the mineral oil and mining industry and anywhere slurry of high volume-speed -.
~ 20 is to be delivered at a high pressure. ~
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Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A displacement slurry pump comprising a cylinder having, in coaxial arrangement, a slurry section and an auxiliary liquid section with a diameter greater than that of said slurry section, a reciprocable piston rod in said cylinder carrying a slurry piston in the slurry section with a diameter such that an aperture remains between the periphery of the piston and the wall of the slurry section, and an auxiliary liquid piston with a diameter providing a sealed fitting in the auxiliary liquid section of said cylinder, said slurry pistion and said auxiliary liquid piston being separated on said piston rod by at least one stroke length, said slurry section being closed at its end farthest from said auxiliary liquid section and provided adjacent said end with valved slurry inlet means and valved slurry outlet means, said auxiliary liquid section being provided adjacent the slurry section with valved means for introducing auxiliary liquid at a pressure greater than the pressure, at said slurry inlet means, said slurry section being closed at its end farthest from said piston rod passing through packing gland means in said closed end of said slurry section, flange means attached to the inner wall of said closed end of said slurry section, thereby forming an auxiliary liquid compartment in said slurry section, said flange means being provided with an aperture larger than the cross-section of said piston rod through which said piston rod passes relatively loosely, and external valved duct means connecting said auxiliary liquid compartment with said auxiliary liquid section at a locus adjacent the slurry section.
2. A pump according to claim 1 wherein a second slurry section is provided in said cylinder on the other side of said auxiliary liquid section from said slurry section, said second slurry section having a diameter smaller than that of said auxiliary liquid section, and a second slurry piston is provided on said piston rod in said second slurry section, said second slurry piston having a diameter such that an aperture remains between the periphery of the piston and the wall of said second slurry section, said second slurry piston and said auxiliary liquid piston being separated on said piston rod by at least one stroke length, said auxiliary liquid section also being provided adjacent said second slurry section with valved means for introducing auxiliary liquid at a pressure greater than the slurry inlet pressure, said second slurry section being closed at its end farthest from said auxiliary liquid section and provided adjacent said end with valved slurry inlet means and valved slurry outlet means, said piston rod passing through packing gland means in the closed end of said second slurry section, flange means attached to the inner walls of the closed end of said second slurry section, thereby forming an auxiliary liquid compartment in said second slurry section, said flange means being provided with an aperture larger than the cross-section of said piston rod through which said piston rod passes relatively loosely, and external valved duct means connecting the auxiliary liquid compartment in said second slurry section with said auxiliary liquid section at a locus adjacent said second slurry section.
3. A multiple cylinder pumping system comprising a plurality of interconnected pumps as defined in claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA241,106A CA1037778A (en) | 1975-12-04 | 1975-12-04 | Displacement slurry pump |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA241,106A CA1037778A (en) | 1975-12-04 | 1975-12-04 | Displacement slurry pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1037778A true CA1037778A (en) | 1978-09-05 |
Family
ID=4104668
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA241,106A Expired CA1037778A (en) | 1975-12-04 | 1975-12-04 | Displacement slurry pump |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1037778A (en) |
-
1975
- 1975-12-04 CA CA241,106A patent/CA1037778A/en not_active Expired
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