CA1162104A - Device for pumping free-flowing media - Google Patents
Device for pumping free-flowing mediaInfo
- Publication number
- CA1162104A CA1162104A CA000373760A CA373760A CA1162104A CA 1162104 A CA1162104 A CA 1162104A CA 000373760 A CA000373760 A CA 000373760A CA 373760 A CA373760 A CA 373760A CA 1162104 A CA1162104 A CA 1162104A
- Authority
- CA
- Canada
- Prior art keywords
- separating
- piston
- pump
- medium
- separating piston
- 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
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/14—Pistons, piston-rods or piston-rod connections
- F04B53/142—Intermediate liquid-piston between a driving piston and a driven piston
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B13/00—Pumps specially modified to deliver fixed or variable measured quantities
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/14—Pistons, piston-rods or piston-rod connections
- F04B53/143—Sealing provided on the piston
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections
- F04B53/162—Adaptations of cylinders
- F04B53/164—Stoffing boxes
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Details Of Reciprocating Pumps (AREA)
- Reciprocating Pumps (AREA)
- Nozzles (AREA)
- Infusion, Injection, And Reservoir Apparatuses (AREA)
- Sampling And Sample Adjustment (AREA)
- Control Of The Air-Fuel Ratio Of Carburetors (AREA)
- Sorption Type Refrigeration Machines (AREA)
Abstract
A B S T R A C T :
Device for pumping free-flowing media, in particular abrasive fluids, whereby the suction and pressure stroke respectively of a displacement pump is transmitted via an operation medium to a separating piston free movable within a separating cylinder and reciprocally spring loaded by springs, said piston admitting the pumping medium and keeping it away from said displacement pump. Said separating piston can at the same time serve as a metering device for a fluid additive (48) which is pressed by said displacement pump, upon pressure stroke, past said separating piston and into said pumping medium.
Device for pumping free-flowing media, in particular abrasive fluids, whereby the suction and pressure stroke respectively of a displacement pump is transmitted via an operation medium to a separating piston free movable within a separating cylinder and reciprocally spring loaded by springs, said piston admitting the pumping medium and keeping it away from said displacement pump. Said separating piston can at the same time serve as a metering device for a fluid additive (48) which is pressed by said displacement pump, upon pressure stroke, past said separating piston and into said pumping medium.
Description
-t J 6~104 The invention rel.ates to a device for pumping free-flowing media, in particular abrasive fluids, slurries, solid suspensions or the like using a displacement pump interposed between two check valves in the delivery line, said pump suctioning the pumping medium upon its suction stroke and passing on said medium upon its pressure stroke, whereby a separating cylinder with an axially free movable separating piston therein is arranged between the delivery line and the working side of the pump, at the one face whereof is located the pumping medium and at the other face whereof is located an operation medium admitted by the pump, said piston having a somewhat smaller diameter than the separating cylinder.
When pumping solid suspensions and abrasive fluids thers is the risk of damage to those parts of the pump which come into contact w.~th the pumping medium. For this reason diaphragm pumps are primarily used instead of piston pumps for such pumping media. These, too, are subject to a high wear and tear, as the diaphlagm is under a great strain during pumping operation. Similarly diaphragm pumps cannot be used for p~mping high temperature fluids.
~' ~ .
When pumping solid suspensions and abrasive fluids thers is the risk of damage to those parts of the pump which come into contact w.~th the pumping medium. For this reason diaphragm pumps are primarily used instead of piston pumps for such pumping media. These, too, are subject to a high wear and tear, as the diaphlagm is under a great strain during pumping operation. Similarly diaphragm pumps cannot be used for p~mping high temperature fluids.
~' ~ .
- 2 ~ 1l 62104 A pumping device of the type initiall~ described is known ~printed German application 1 453 576 laid open (Auslegeschrift) 1 453 576 ), havlng a se~arating piston can freely move with clearance within the separating cylinder and is not sealed from the inner wall of the separating cylinder, with the result that the pumped medium can flow pa~ the separating piston during operation and into the operation medium. In order to prevent larger quantities of pumping medium from getting into the operation medium, there is provided between separating cylinder and displacement pump a long conduit and an auxiliary pump which constantly pumps the operation medium into the conduit -- between displacement pump and separating piston.
In the case of this known pumping device the pumping medium penetrated into the operation medium is in fact kept away from the displacement pump sufficiently reliably but it is still necessary for the conduit at least between displacement pump and separating cylinder to be composed of a material which cannot be corroded by the pumping medium. Moreover separating cylinders and separating pistons are subject to high wear and tear when pumping solid substance suspensions, since the pumping medium constantly flows between separating piston and cylinder and solid particles may become firmly lodged in the gap. Even if slurries are to be pumped , difficulties can occur, since these block up the gap between separating piston and separating cylinder thus impeding the free movability of the separating piston. Furthermore the known pumping device only functions if the separating piston has approximately the same density as the liquid to be pumped.
The object of the invention is toprovide a very simple and robust device for pumping free-flowing media of the type initially described, whereby the pumping medium does not penetrate into the operation medium and does not impede the movement of the separating piston within the separating cylinder.
~ 3 - 1l 62104 This problem is solved by the invention in that the separating piston is spring loaded by at least one spring element acting against the pressure direction of the pump and is sealed around its circumference against the pumping medium.
This arrangement has the advantage that no pumping medium can penetrate into the operation medium and both during pressure stroke as well as suction stroke a small amount of operation medium flows past the separa~ing piston into the pumping medium which flushes the annular gap and the packing therein. This effect is produced due to the fact that in addition to the pumping force a force to overcome the spring pressure must be applied by the pump upon press-ure stroke, thus producing a pressure differential in the operation medium and the pumping medium, which allows the operation medium to flow past the separating piston.
Upon suction stroke, however, the spring element lets the separating piston advance enabling the operation medium to pass via the annular gap between separating piston and separating cylinder into the pumping medium.
The separating piston subdivides the separating cylinder into two cylinder chambers, which with the separating piston in its final positions have 2 smaller volume than the operation ~nedium moved by the pump during pressure and suction stroke. In doing so the working s~e of the pump is expediently connected to a supply tank, which is closed to the pump upon pressure stroke. In this way an increase in the pressure of the operation medium is achieved at the end of the pressure stroke, if the separating piston has reached its extreme position. As a result of the pressure differential between operation medium and pumping medium a certain volume of the operation medium can flow past the packing into the pumping medium and flush the packing and peripheral edge of the separating piston free from pumping means, thus ensuring a perfect sealing of the separating piston at the separating cylinder, when the displacement pump ~egins its suction stroke and the separat~ng piston once again suctions pumping medium.
l J 62104 ~ this purpose the separating piston is provided with at least one gasket haYlng a sealing lip continguous to the inner wall of the cylinder and being directed towards the cylinder chamber filled with pumping medium. This sealing lip is flushed and cleaned by the operation medium flowing through the annular gap between separating piston and inner wall of the separating cy-linder. In neutral position the sealing lip then fits closely to the inner wall of the separating cylinder so that no pumping medium can flow back into the operation medium.
Betweer. the supply tank and the working side of the pump a first non-return valve preloaded against the supply tank and a second non-return valve preloaded against the working side of the pump is respectively arranged and controlled by the sepa-rating piston. By this construction the inlet from the supply tank remains closed while the pump carries out its pressure stroke and the second non-return valve is opened at the end of the suction stroke of the separating piston; the first non-return valve, however, only opens when there is a low pressure on the working side of the displacement pump, which exceeds the spring force closing the first non-return valve.
To control the second non-return valve the latter can have a tappet which protudes into the separatin~ cylinder and is admitted by the separating piston in the last phase of the suction stroke. Hereby it is particularly expedient for the valve bodies of the first and second non-return valves to be pressed on their seats by a common valve spring~
On the front face of the separating piston facing the dis-placement pump a spring can be arranged which retards the action of the separating piston in its suction stroke and softens the impact of the separating piston on the separating cylinder casing.
For this purpose the separating cylinder has stops in both cylinder chambers which reciprocally limit the stroke of the separating piston and the one cylinder chamber of the separating cylinder can be connected by one conduit to the delivery line and the other cylinder chamber by one conduit ~
to the working side of the piston pump actLng as displacement pu~.
l 1 6~104 It is particularly expedient to adapt the si~e of the flow inlet between separating cylinder and separating piston to meet the volume of the operation medium which is to be pressed into the pumping medium with each pressure stroke. Such a construction ls then particularly advantageous if a metered volume of a particular medium is to be added to the pumping medium with every stroke of the pump. In this case the operation medium is composed of this additive which is topped up constantly from the supply tank. If the pumping medium is a bauxite slurry, for example, to which sodium hydroxide solution is to be added during pump operation, then the supply tank can contain the sodium hydroxide solution to be added to the pumping medium. In other cases the supply tank contains a flushing liquid or the operation medium, which can be any suitable hydraulic fluid, for e.g. an oil or water, which exerts no adverse effect on the pumping medlum if added thereto in small quantities during the pump operation.
Further features and advantages of the invention will be apparent from the following description, in which a preferred embodiment of the invention is more closely illustrated by means of an example. It shows :
Fig. 1 a pumping device according to the invention in a schematic sectional view and Fig. 2 ltem II of Fig. 1 on an enlarged scale, showing the packing or sealing of the separating piston at the separating cylinder.
I ~ 6~104 The drawings show a pumping device 10 for the pumping of free-flowing media, in particular an abrasive fluld such as e.g. a bauxite slurry which is hereinafter abbreviated as " pumping medium " and identified in the drawing as 1 1 . The pumping medium flows in the direction of arrow 12 in a pump hose 13, in which two bypass valves 14 and 15 are located, said valves being ball valves, and are housed in a valve casing 16. Between the two bypass valves 14 and 15 ~here is a pipe joint socket 17 to which a conduit 18 is connected, leading to a separating cylinder, marked collectively as 19.
In the separating cylinder 19 there is a separating piston 20 freely displaceable in axial direction, which subdivides the separating cylinder 19 into a lower cylinder chamber 19a and an upper cylinder chamber 19b. The conduit 18 already mentioned is connected to the lower cylinder chamber 19a, which leads to the valve casing 16 ofthe pump hose 13. A conduit 21, filled with an operation medium 40, connected to the working side 22, a displacement pump 23, which is a piston pump in the embodiment example illustrated enters into the upper cylinder chamber 19b. The pump housing is marked 24 and the pump piston bears the reference number 25. The piston rod 26, only schematically indicated here, acts upon the piston 25, which is moved by the crankshaft 27 and imparts a reciprocal movement to the piston 25.
As seen from Fig. 1 the separating piston 20 has a peripheral edge 28 enlarged in axial direction, which protrudes beyond the lower face 29 of the separating piston and touches the one face 30 of the separating cylinder upon pressure stroke.
On the opposite face 39 of the separating piston a protuber-ance 31 is fitted which can touch the upper face 32 of the separating cylinder and hereby limit the suction stroke of the separating cylinder.
- 7 ~ ll 6~
From Fig. 2 it is evident that the separating piston 20 has a diameter d which is somewhat smaller than the diameter D of the separating cylinder, leaving as a result an annular gap 33 between the separating cylinder 19 and the separating piston 20. This annular gap is sealed by two lip seals 34 arranged consecutively in axial direction which are each located respectively in a peripheral groove 35 of the separating piston and have a sealing lip 37 contiguous to the inner wall of the cylinder 36, said lip being directed at the cylinder chamber 19a filled with pumping medium 11. The annular groove has a quite definite dimension which is explained in more detail further below.
In the upper ront cover38 of the separating cylinder 19 there is a bore 41 through which the tappet 42 of a disk valve 43 protrudes into the upper cylinder chambe~ 19b of the separating cylinder. The disk valve 43 is located together with a ball return valve 44 in a valve casing 45, which is fixed to the upper front cover 38 of the separating cylinder 19 and belongs to a hose 46 which leads to a supply tank 47, in which the operation medium or a special flushing liquid 48 is located.
As seen from Fig. 1 the spherical closure of the non-return valve 44 and the valve disk of the disk valve 43 are pressed against their seats by a valve spring 49 common to both and kept closed. The disk valve 43 is raised from its seat, if the annular enlargement 28 of the separating piston 20 pushes against the end of the valve tappet 42 protruding into the cylinder chamber 19b and displaces this in axial direction, if the separating piston 20 in Fig. 1 moves upwards.
1 1 62~4 When the displacement pump 23 is not operable the separating piston 20 is held approximately in the middle of the separating cylinder 19 by two springs 50 and 51, said spring 50 being located in the lower cylinder chamber 19a and said spring 51 being located in the upper cylinder chamber 19b of the separating cylinder 19.
The mode of operation of the device is as follows :
If the piston 25 of the displacement pump 23 is moved in a downwards direction by the connecting rod 26 in Fig. 1 and ii said piston carries out its pressure stroke, the operation medium 40 located within the conduit 21 presses on the upper face 39 of the separating piston with the result that the former likewise is pressed downwards in Fig. 1 and exerts a pressure on the pumping medium 11 located in the conduit 18 and in the valve casing 16. With this increase in pressure the non return valve 15 in the valve casing 16 is kept closed, whereas the non return valve 14 opens and the pumping medium is passed along in the direction of the arrow 12 within the delivery line 13.
As the separating piston 20 i5 under the action of spring 50, the liquid pressure produced in the conduit 21 by piston 25 of the displacement pump must be greater than the pressure for pumping the pumping medium within the conduit 18 and the delivery line 13, if the separating piston 20 in the separating cylinder 19 is pressed down-wards. As a result of the pressure differential in the conduits 21 and 18 the operation medium 40 flows through the annular gap 33 between separating piston 20 and separating cylinder 19 past the sealing lips 37 into the pumping medium, and in doing so flushes the seals 34.
The same effect also occurs if the separating piston 20 contacts the face 30 of the separating cylinder 19, before the piston 25 of the displacement pump 23 reaches its bottom dead centre, if the cylinder chambers 19a and 19b in the final positions of the separating piston 20 have a smaller volume than the operation medium displaced by thP
pump 23 upon pressure and suctlon stro~e.
- 9 - l l 62104 When the piston 25 has reached its bottom dead centre and the piston pump 23 begins its suction stroke, the separa~ing piston 20 is carried upwards by the low pressure arising in the conduit 21, whtch for its part~
produces a low pressure in the conduit 13 and in the valve casing 16, whereby the non-return valve 14 is closed and the non-return valve 15 in the delivery line 13 opened and pumping medium suctioned out of the delivery line 13.
sefore the separating piston 20 comes to rest at the upper face 32 of the separating cylinder 19, the outer annular enlargement 28 on the separating piston 20 pushes against the tappet 42 of the disk valve 43 and lifts this from its seat. As the separating piston 20 is retarded in its up stroke by the spring 51, but the piston 25 of the displacement pump 23 however continues its suction stroke after the separating piston 20 has contacted the upper face 32 of the separating cylinder 19 , a low pressure occurs in the conduit 21. As the sealing lips 37 of the lip seals 34 are directed to the lower cylinder chamber 19a filled with pumping medium 11, said sealing lips 37 are pressed by the pumping medium 11 firmly against the inner wall 36 of the separating c~linder. Due to the simultaneously effective lower pressure in the interior of the valve casing 45 the non-return valve 44 is lifted from its seat, with the result that the fluid 4~ in the supply tank 47 can flow through the valve casing 45 into the cylinder chamber 19b and supplement the operation medium 40, while the piston 25 of displacement pump 23 continues its suction stroke.
The cylinder chamber 19b and the conduit 21 are then once again completely filled with fluid, when the piston 25 reaches its upper dead centre.
It is evident that the pumping device according to the invention can be used simultaneously as a metering device, with which a fluid 48 present in the s~pply tank 47 can be added in metered quantity to the pumping medium 11, whereby the force of the spring 50, the cylinder chambers 19a and 19b and the width of the annular gap 33 can be attuned to one another in such a way that with every suction stroke a quite definite quantity of fluid 4~ passes into the conduit 21 and is pressed past the lip seals 34 into i 3 62104 the pumping rnedium 11 upon pressure stroke. In this way the fluid additive 48 can be the same fluid as the operation medium 40. It is, however, also possible to use a fluid additive which is different from the operation fluid, as when using the injection inlet arrangement for the fluid additive in the upper face 38 of the separating cylinder 19 as shown, - an arrangement not insignificant to the invention - there is hardly any mixing of the operation fluid in conduit 21 and the fluid additive injected into the upper cylinder chamber ~9b.
The invention can be used in industry for the pumping of free-flowing substances, in particular aggressive and abrasive slurries such as bauxite suspensions or carbon slurries. As operation medium a hydraulic fluid e.g. a mineral oil, but also water, sodium hydroxide solution or another additional fluid can be used, which is to be injected into the pumping medium and can be supplemented or refllled from the additional tanks 48.
The invention is not restricted to the embodiment example.
It is also possible, e.g. to use even differently formed and differently controlled valves for the injection of the fluid additive, without hereby exceeding the scope of the invention.
,
In the case of this known pumping device the pumping medium penetrated into the operation medium is in fact kept away from the displacement pump sufficiently reliably but it is still necessary for the conduit at least between displacement pump and separating cylinder to be composed of a material which cannot be corroded by the pumping medium. Moreover separating cylinders and separating pistons are subject to high wear and tear when pumping solid substance suspensions, since the pumping medium constantly flows between separating piston and cylinder and solid particles may become firmly lodged in the gap. Even if slurries are to be pumped , difficulties can occur, since these block up the gap between separating piston and separating cylinder thus impeding the free movability of the separating piston. Furthermore the known pumping device only functions if the separating piston has approximately the same density as the liquid to be pumped.
The object of the invention is toprovide a very simple and robust device for pumping free-flowing media of the type initially described, whereby the pumping medium does not penetrate into the operation medium and does not impede the movement of the separating piston within the separating cylinder.
~ 3 - 1l 62104 This problem is solved by the invention in that the separating piston is spring loaded by at least one spring element acting against the pressure direction of the pump and is sealed around its circumference against the pumping medium.
This arrangement has the advantage that no pumping medium can penetrate into the operation medium and both during pressure stroke as well as suction stroke a small amount of operation medium flows past the separa~ing piston into the pumping medium which flushes the annular gap and the packing therein. This effect is produced due to the fact that in addition to the pumping force a force to overcome the spring pressure must be applied by the pump upon press-ure stroke, thus producing a pressure differential in the operation medium and the pumping medium, which allows the operation medium to flow past the separating piston.
Upon suction stroke, however, the spring element lets the separating piston advance enabling the operation medium to pass via the annular gap between separating piston and separating cylinder into the pumping medium.
The separating piston subdivides the separating cylinder into two cylinder chambers, which with the separating piston in its final positions have 2 smaller volume than the operation ~nedium moved by the pump during pressure and suction stroke. In doing so the working s~e of the pump is expediently connected to a supply tank, which is closed to the pump upon pressure stroke. In this way an increase in the pressure of the operation medium is achieved at the end of the pressure stroke, if the separating piston has reached its extreme position. As a result of the pressure differential between operation medium and pumping medium a certain volume of the operation medium can flow past the packing into the pumping medium and flush the packing and peripheral edge of the separating piston free from pumping means, thus ensuring a perfect sealing of the separating piston at the separating cylinder, when the displacement pump ~egins its suction stroke and the separat~ng piston once again suctions pumping medium.
l J 62104 ~ this purpose the separating piston is provided with at least one gasket haYlng a sealing lip continguous to the inner wall of the cylinder and being directed towards the cylinder chamber filled with pumping medium. This sealing lip is flushed and cleaned by the operation medium flowing through the annular gap between separating piston and inner wall of the separating cy-linder. In neutral position the sealing lip then fits closely to the inner wall of the separating cylinder so that no pumping medium can flow back into the operation medium.
Betweer. the supply tank and the working side of the pump a first non-return valve preloaded against the supply tank and a second non-return valve preloaded against the working side of the pump is respectively arranged and controlled by the sepa-rating piston. By this construction the inlet from the supply tank remains closed while the pump carries out its pressure stroke and the second non-return valve is opened at the end of the suction stroke of the separating piston; the first non-return valve, however, only opens when there is a low pressure on the working side of the displacement pump, which exceeds the spring force closing the first non-return valve.
To control the second non-return valve the latter can have a tappet which protudes into the separatin~ cylinder and is admitted by the separating piston in the last phase of the suction stroke. Hereby it is particularly expedient for the valve bodies of the first and second non-return valves to be pressed on their seats by a common valve spring~
On the front face of the separating piston facing the dis-placement pump a spring can be arranged which retards the action of the separating piston in its suction stroke and softens the impact of the separating piston on the separating cylinder casing.
For this purpose the separating cylinder has stops in both cylinder chambers which reciprocally limit the stroke of the separating piston and the one cylinder chamber of the separating cylinder can be connected by one conduit to the delivery line and the other cylinder chamber by one conduit ~
to the working side of the piston pump actLng as displacement pu~.
l 1 6~104 It is particularly expedient to adapt the si~e of the flow inlet between separating cylinder and separating piston to meet the volume of the operation medium which is to be pressed into the pumping medium with each pressure stroke. Such a construction ls then particularly advantageous if a metered volume of a particular medium is to be added to the pumping medium with every stroke of the pump. In this case the operation medium is composed of this additive which is topped up constantly from the supply tank. If the pumping medium is a bauxite slurry, for example, to which sodium hydroxide solution is to be added during pump operation, then the supply tank can contain the sodium hydroxide solution to be added to the pumping medium. In other cases the supply tank contains a flushing liquid or the operation medium, which can be any suitable hydraulic fluid, for e.g. an oil or water, which exerts no adverse effect on the pumping medlum if added thereto in small quantities during the pump operation.
Further features and advantages of the invention will be apparent from the following description, in which a preferred embodiment of the invention is more closely illustrated by means of an example. It shows :
Fig. 1 a pumping device according to the invention in a schematic sectional view and Fig. 2 ltem II of Fig. 1 on an enlarged scale, showing the packing or sealing of the separating piston at the separating cylinder.
I ~ 6~104 The drawings show a pumping device 10 for the pumping of free-flowing media, in particular an abrasive fluld such as e.g. a bauxite slurry which is hereinafter abbreviated as " pumping medium " and identified in the drawing as 1 1 . The pumping medium flows in the direction of arrow 12 in a pump hose 13, in which two bypass valves 14 and 15 are located, said valves being ball valves, and are housed in a valve casing 16. Between the two bypass valves 14 and 15 ~here is a pipe joint socket 17 to which a conduit 18 is connected, leading to a separating cylinder, marked collectively as 19.
In the separating cylinder 19 there is a separating piston 20 freely displaceable in axial direction, which subdivides the separating cylinder 19 into a lower cylinder chamber 19a and an upper cylinder chamber 19b. The conduit 18 already mentioned is connected to the lower cylinder chamber 19a, which leads to the valve casing 16 ofthe pump hose 13. A conduit 21, filled with an operation medium 40, connected to the working side 22, a displacement pump 23, which is a piston pump in the embodiment example illustrated enters into the upper cylinder chamber 19b. The pump housing is marked 24 and the pump piston bears the reference number 25. The piston rod 26, only schematically indicated here, acts upon the piston 25, which is moved by the crankshaft 27 and imparts a reciprocal movement to the piston 25.
As seen from Fig. 1 the separating piston 20 has a peripheral edge 28 enlarged in axial direction, which protrudes beyond the lower face 29 of the separating piston and touches the one face 30 of the separating cylinder upon pressure stroke.
On the opposite face 39 of the separating piston a protuber-ance 31 is fitted which can touch the upper face 32 of the separating cylinder and hereby limit the suction stroke of the separating cylinder.
- 7 ~ ll 6~
From Fig. 2 it is evident that the separating piston 20 has a diameter d which is somewhat smaller than the diameter D of the separating cylinder, leaving as a result an annular gap 33 between the separating cylinder 19 and the separating piston 20. This annular gap is sealed by two lip seals 34 arranged consecutively in axial direction which are each located respectively in a peripheral groove 35 of the separating piston and have a sealing lip 37 contiguous to the inner wall of the cylinder 36, said lip being directed at the cylinder chamber 19a filled with pumping medium 11. The annular groove has a quite definite dimension which is explained in more detail further below.
In the upper ront cover38 of the separating cylinder 19 there is a bore 41 through which the tappet 42 of a disk valve 43 protrudes into the upper cylinder chambe~ 19b of the separating cylinder. The disk valve 43 is located together with a ball return valve 44 in a valve casing 45, which is fixed to the upper front cover 38 of the separating cylinder 19 and belongs to a hose 46 which leads to a supply tank 47, in which the operation medium or a special flushing liquid 48 is located.
As seen from Fig. 1 the spherical closure of the non-return valve 44 and the valve disk of the disk valve 43 are pressed against their seats by a valve spring 49 common to both and kept closed. The disk valve 43 is raised from its seat, if the annular enlargement 28 of the separating piston 20 pushes against the end of the valve tappet 42 protruding into the cylinder chamber 19b and displaces this in axial direction, if the separating piston 20 in Fig. 1 moves upwards.
1 1 62~4 When the displacement pump 23 is not operable the separating piston 20 is held approximately in the middle of the separating cylinder 19 by two springs 50 and 51, said spring 50 being located in the lower cylinder chamber 19a and said spring 51 being located in the upper cylinder chamber 19b of the separating cylinder 19.
The mode of operation of the device is as follows :
If the piston 25 of the displacement pump 23 is moved in a downwards direction by the connecting rod 26 in Fig. 1 and ii said piston carries out its pressure stroke, the operation medium 40 located within the conduit 21 presses on the upper face 39 of the separating piston with the result that the former likewise is pressed downwards in Fig. 1 and exerts a pressure on the pumping medium 11 located in the conduit 18 and in the valve casing 16. With this increase in pressure the non return valve 15 in the valve casing 16 is kept closed, whereas the non return valve 14 opens and the pumping medium is passed along in the direction of the arrow 12 within the delivery line 13.
As the separating piston 20 i5 under the action of spring 50, the liquid pressure produced in the conduit 21 by piston 25 of the displacement pump must be greater than the pressure for pumping the pumping medium within the conduit 18 and the delivery line 13, if the separating piston 20 in the separating cylinder 19 is pressed down-wards. As a result of the pressure differential in the conduits 21 and 18 the operation medium 40 flows through the annular gap 33 between separating piston 20 and separating cylinder 19 past the sealing lips 37 into the pumping medium, and in doing so flushes the seals 34.
The same effect also occurs if the separating piston 20 contacts the face 30 of the separating cylinder 19, before the piston 25 of the displacement pump 23 reaches its bottom dead centre, if the cylinder chambers 19a and 19b in the final positions of the separating piston 20 have a smaller volume than the operation medium displaced by thP
pump 23 upon pressure and suctlon stro~e.
- 9 - l l 62104 When the piston 25 has reached its bottom dead centre and the piston pump 23 begins its suction stroke, the separa~ing piston 20 is carried upwards by the low pressure arising in the conduit 21, whtch for its part~
produces a low pressure in the conduit 13 and in the valve casing 16, whereby the non-return valve 14 is closed and the non-return valve 15 in the delivery line 13 opened and pumping medium suctioned out of the delivery line 13.
sefore the separating piston 20 comes to rest at the upper face 32 of the separating cylinder 19, the outer annular enlargement 28 on the separating piston 20 pushes against the tappet 42 of the disk valve 43 and lifts this from its seat. As the separating piston 20 is retarded in its up stroke by the spring 51, but the piston 25 of the displacement pump 23 however continues its suction stroke after the separating piston 20 has contacted the upper face 32 of the separating cylinder 19 , a low pressure occurs in the conduit 21. As the sealing lips 37 of the lip seals 34 are directed to the lower cylinder chamber 19a filled with pumping medium 11, said sealing lips 37 are pressed by the pumping medium 11 firmly against the inner wall 36 of the separating c~linder. Due to the simultaneously effective lower pressure in the interior of the valve casing 45 the non-return valve 44 is lifted from its seat, with the result that the fluid 4~ in the supply tank 47 can flow through the valve casing 45 into the cylinder chamber 19b and supplement the operation medium 40, while the piston 25 of displacement pump 23 continues its suction stroke.
The cylinder chamber 19b and the conduit 21 are then once again completely filled with fluid, when the piston 25 reaches its upper dead centre.
It is evident that the pumping device according to the invention can be used simultaneously as a metering device, with which a fluid 48 present in the s~pply tank 47 can be added in metered quantity to the pumping medium 11, whereby the force of the spring 50, the cylinder chambers 19a and 19b and the width of the annular gap 33 can be attuned to one another in such a way that with every suction stroke a quite definite quantity of fluid 4~ passes into the conduit 21 and is pressed past the lip seals 34 into i 3 62104 the pumping rnedium 11 upon pressure stroke. In this way the fluid additive 48 can be the same fluid as the operation medium 40. It is, however, also possible to use a fluid additive which is different from the operation fluid, as when using the injection inlet arrangement for the fluid additive in the upper face 38 of the separating cylinder 19 as shown, - an arrangement not insignificant to the invention - there is hardly any mixing of the operation fluid in conduit 21 and the fluid additive injected into the upper cylinder chamber ~9b.
The invention can be used in industry for the pumping of free-flowing substances, in particular aggressive and abrasive slurries such as bauxite suspensions or carbon slurries. As operation medium a hydraulic fluid e.g. a mineral oil, but also water, sodium hydroxide solution or another additional fluid can be used, which is to be injected into the pumping medium and can be supplemented or refllled from the additional tanks 48.
The invention is not restricted to the embodiment example.
It is also possible, e.g. to use even differently formed and differently controlled valves for the injection of the fluid additive, without hereby exceeding the scope of the invention.
,
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device for pumping abrasive fluids, slurries, solid suspensions or the like, using a displacement pump interposed between two check valves in a delivery line, said pump suctioning pumped medium through one valve upon its suction stroke and passing on said pumped medium through the other valve upon its pressure stroke, said device including a separating cylinder with an axially free movable separating piston between said delivery line and the displacement pump, one face of said piston being engaged by the pumped medium and the other face thereof being engaged by an operating medium pressurized by said displacement pump, said piston having a slightly smaller diameter than said separating cylinder spring means acting on said separating piston against the pressure direction of said pump and means sealing the cir-cumference of said separating piston against said pumped med-ium, said separating piston moving between final positions at either end of said separating cylinder to displace a smaller volume of said pumped medium than the operating medium moved by the associated suction or pressure stroke of said pump, a supply tank and means connecting said tank to the operating medium side of said pump in a closed position and means open-ing said connection means on the suction stroke of said pump, said sealing means between said separating piston and the inner wall of said separating cylinder, comprising a gasket having a sealing lip contiguous to the inner wall of the cylinder and directed towards said pumped medium, and being arranged such that excess operating medium per stroke can pass the clearance between said separating piston and said separating cylinder.
2. A device as caimed in claim 1, including a first non-return valve and a second non-return valve between said supply tank and said pressure side of said pump, said first non-return vallve being pre-loaded against said supply tank and said second non-return valve being preloaded against said pressure side of said pump, said second non-return valve being controlled by said separating piston.
3. A device as claimed in claim 2, including a tappet on said second non-return valve which protrudes into said separating cylinder and is engaged by said separating piston in the last phase of the suction stroke.
4. A device as claimed in claim 2, including a valve spring common to both valves pressing said first non-return valve and said second non-return valve against their seat.
5. A device as claimed in claim 3, including a valve spring common to both valves pressing said first non-return valve and said second non-return valve against their seat.
6. A device as claimed in claim 1, including a spring at the-end of said separating piston facing said dis-placement pump, said spring retarding said separating piston on the suction stroke.
7. A device as claimed in claim 3, wherein the size of the clearance between said separating cylinder and said separating piston is adapted to the volume of the medium which is to be forced into the pumped medium on each pressure stroke.
8. A device as claimed in claim 1, wherein said supply tank contains a special flushing fluid to be added to said pumped medium.
9. A device as claimed in claim 2, including a spring at the end of said separating piston facing said displacement pump, said spring retarding said separating piston on the suction stroke.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3012028.6 | 1980-03-28 | ||
| DE19803012028 DE3012028A1 (en) | 1980-03-28 | 1980-03-28 | DEVICE FOR CONVEYING FLOWABLE MEDIA |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1162104A true CA1162104A (en) | 1984-02-14 |
Family
ID=6098613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000373760A Expired CA1162104A (en) | 1980-03-28 | 1981-03-24 | Device for pumping free-flowing media |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0036945B1 (en) |
| JP (1) | JPS56165780A (en) |
| AT (1) | ATE5159T1 (en) |
| AU (1) | AU6857781A (en) |
| BR (1) | BR8101865A (en) |
| CA (1) | CA1162104A (en) |
| DE (2) | DE3012028A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8940250B2 (en) | 2009-07-09 | 2015-01-27 | Basf Se | Method of conveying liquids |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8105988L (en) * | 1981-10-09 | 1983-04-10 | Hk Eng Ab | DEPLACEMENT TYPE PUMP |
| DE3929605A1 (en) * | 1989-09-06 | 1991-03-14 | Tuczek Franz | Pump used in vehicles suspension - transfers gas between containers and uses column of oil to adjust piston stroke |
| NL9001676A (en) * | 1990-07-24 | 1992-02-17 | Holthuis Bv | PUMP SYSTEM. |
| US5310321A (en) * | 1990-07-24 | 1994-05-10 | Baker Hughes Incorporated | Pump system |
| NL1004890C2 (en) | 1996-12-24 | 1998-06-25 | Envirotech Pumpsystems Netherl | Pump system particularly suitable for pumping hot media. |
| DE19903061C2 (en) * | 1999-01-26 | 2002-11-21 | Emmerich Josef Pumpenfab | displacement |
| DE102005059831B3 (en) * | 2005-12-14 | 2007-06-21 | Siemens Ag | high pressure pump |
| EP2154371B1 (en) * | 2008-08-14 | 2018-09-19 | Bran + Lübbe GmbH | Pumping device |
| DE102013114320A1 (en) * | 2013-12-18 | 2015-06-18 | Mhwirth Gmbh | Hot sludge pump |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB350817A (en) * | 1929-08-28 | 1931-06-18 | Alexandre Lamblin | |
| DE735165C (en) * | 1940-05-25 | 1943-05-07 | Bernh Draeger | Horizontal, double-acting high-pressure transfer pump for manual operation, especially for filling with oxygen |
| US2497300A (en) * | 1947-01-29 | 1950-02-14 | Du Pont | Floating piston pump |
| US2753805A (en) * | 1954-06-24 | 1956-07-10 | Boivinet Jean | Regulator for diaphragm pumps |
| DE1054328B (en) * | 1957-12-23 | 1959-04-02 | Karl Schlecht Dipl Ing | Diaphragm pump with automatic flow control |
| GB983089A (en) * | 1962-06-19 | 1965-02-10 | Herbert Ott | Improvements in or relating to pump drive mechanisms |
| DE7303301U (en) * | 1973-01-30 | 1974-04-04 | Feluwa Schlesiger & Co Kg | Diaphragm piston pump |
| FR2273961A1 (en) * | 1974-06-06 | 1976-01-02 | Venditti Bernard | Reciprocating pump or compressor sealing system - additional chamber sealed from driving mechanism collects escaped liquid |
| US4157057A (en) * | 1976-11-18 | 1979-06-05 | Reed Tool Company | Single acting piston |
| GB1565879A (en) * | 1977-08-19 | 1980-04-23 | British Hydromechanics | High pressure piston pumps |
-
1980
- 1980-03-28 DE DE19803012028 patent/DE3012028A1/en not_active Withdrawn
-
1981
- 1981-02-25 AT AT81101334T patent/ATE5159T1/en not_active IP Right Cessation
- 1981-02-25 EP EP81101334A patent/EP0036945B1/en not_active Expired
- 1981-02-25 DE DE8181101334T patent/DE3161257D1/en not_active Expired
- 1981-03-20 AU AU68577/81A patent/AU6857781A/en not_active Abandoned
- 1981-03-23 JP JP4052081A patent/JPS56165780A/en active Pending
- 1981-03-24 CA CA000373760A patent/CA1162104A/en not_active Expired
- 1981-03-27 BR BR8101865A patent/BR8101865A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8940250B2 (en) | 2009-07-09 | 2015-01-27 | Basf Se | Method of conveying liquids |
Also Published As
| Publication number | Publication date |
|---|---|
| BR8101865A (en) | 1981-09-29 |
| EP0036945A3 (en) | 1981-11-25 |
| EP0036945A2 (en) | 1981-10-07 |
| AU6857781A (en) | 1981-10-01 |
| JPS56165780A (en) | 1981-12-19 |
| EP0036945B1 (en) | 1983-10-26 |
| ATE5159T1 (en) | 1983-11-15 |
| DE3161257D1 (en) | 1983-12-01 |
| DE3012028A1 (en) | 1981-10-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |