EP2381105B1

EP2381105B1 - Slurry pump

Info

Publication number: EP2381105B1
Application number: EP11161496A
Authority: EP
Inventors: Michael Johannes Staring; Rick Antoon Houtman; Richard Johannes Ruyter
Original assignee: M Staring Beheer BV
Current assignee: M Staring Beheer BV
Priority date: 2010-04-22
Filing date: 2011-04-07
Publication date: 2012-12-19
Anticipated expiration: 2031-04-07
Also published as: EP2381105A1; NL2004596C2

Description

BACKGROUND OF THE INVENTION

The invention relates to a slurry pump, particularly for pumping abrasive slurries or construction slurries. Construction slurries are understood to mean mixtures according to lime and/or cement-tied recipes, such as cement mortar, concrete mortar containing hard pebbles, and Anhydrite. Construction slurries are difficult to pump due to their composition and viscous properties.
A known pump for construction slurry comprises two pump cylinders that connect to a hopper for construction slurry. The pump cylinders each comprise a piston, wherein the pistons alternately make a compression stroke to push mortar out of the pump cylinders. In the hopper a line is placed of which the inlet is always brought straight in front of the opening of the pump cylinder that is about to start the compression stroke. The inversion is ensured by electrically controlled hydraulic switches, for which reason the pump in addition to a hydraulic drive circuit is also provided with an electronic control circuit for the pump cycles. This renders the pump failure prone.
When inverting said inlet the slurry flow in the line comes to a standstill, after which the next compression stroke brings it into motion again. The inverting of the inlet causes a lot of noise, and the abrupt standstill of the slurry flow causes undesirable shockwaves in the slurry lines.
Due to the weight of the construction slurry said pulsation is accompanied by considerable loss of energy. Furthermore the irregular slurry flow is disadvantageous in the continuous pouring of elongated construction parts, poured and flowing floors, as in between each pulse the movement of the line above the mould or floor needs to be interrupted.
Document US 34 94 290 A discloses a slurry pump according to the preamble of claim 1.
It is an object of the invention to provide a slurry pump the operation of which can be controlled with or without a limited electronic control circuit.
It is an object of the invention to provide a slurry pump with which a more regular exiting slurry flow can be achieved.
It is an object of the invention to provide a pump with which with a limited number of pump chambers an evenly exiting slurry flow can be obtained.
It is an object of the invention to provide a pump having an efficient energy consumption regarding the pumping of construction slurry.

SUMMARY OF THE INVENTION

The invention provides a slurry pump according to claim 1.
By means of the rotation of the core the rotor valve ensures the hydraulic control of the hydraulic drive cylinders, as a result of which both the actuation and the control are performed hydraulically. An electric circuit for the pump can therefore remain limited or be left out entirely.
In one embodiment that can be assembled with overview, the hydraulic drive cylinders are each operationally coupled to their own hydraulic exit of the rotor valve.
In one embodiment the inside of the first drive cylinder and the second hydraulic drive cylinder is divided by the pistons into a piston rod side and a bottom side, wherein the hydraulic exit for the first drive cylinder and the hydraulic exit for the second hydraulic drive cylinder are hydraulically connected to the bottom sides of the first hydraulic drive cylinder and second hydraulic drive cylinder, respectively. The compression strokes of the first and second hydraulic drive cylinder can as a result be alternately controlled in the same manner by the supply of hydraulic drive fluid from the rotor valve.
In one embodiment thereof the piston rod sides of the first hydraulic drive cylinder and the second hydraulic drive cylinder are connected to one another with a balancing line. Thus it is achieved that a compression stroke of the first hydraulic cylinder is converted via the balancing line into a simultaneous piston stroke of the second hydraulic drive cylinder and vice versa.
In a particular embodiment thereof, via a one-way valve opening towards the balancing line, the balancing line also connects to a part of the inside of the hydraulic drive cylinder situated in the end range of a compression stroke of the slurry displacer at the bottom side of the piston. In that way it can be achieved that at the end of a compression stroke of the first hydraulic drive cylinder the hydraulic drive fluid can be siphoned over via the one-way valve to the second hydraulic drive cylinder and vice versa for completing its piston stroke. This is particularly advantageous when starting the pump cycle wherein the positions of the first and second hydraulic drive cylinder may still be undetermined.
In one embodiment the hydraulic drive pump, outside of the rotor valve, is connected to the balancing line for a continuous supply of hydraulic drive fluid to the balancing line. In that way it can be achieved that the piston stroke actuated by the hydraulic drive fluid siphoned over, is accelerated by the continuously supplied hydraulic drive fluid. The piston stroke of the second hydraulic drive cylinder is thus completed sooner than the compression stroke of the first hydraulic drive cylinder and vice versa, so that in one of the pump cylinders an already complete column of slurry is ready to be pushed to the slurry outlet when the other hydraulic cylinder is near the end of its compression stroke. As a result a pulse free outflow of the slurry from the slurry outlet can be achieved.
In one embodiment the connections to the bottom sides of the first hydraulic drive cylinder and the second hydraulic drive cylinder, also via a one-way valve opening towards the exit of the rotor valve, connect to a part of the inside of the hydraulic drive cylinder situated in the starting range of a compression stroke of the slurry displacer at the piston rod side of the piston. In that way it can be achieved that at the end of the piston stroke of the first hydraulic drive cylinder the hydraulic drive fluid is able to escape via the one-way valve from the first hydraulic drive cylinder and vice versa in order to complete its piston stroke actuated via the balancing line. This is particularly advantageous when starting up the pump cycle wherein the positions of the first and second hydraulic drive cylinders may still be undetermined.
In one embodiment the rotor valve is provided with a first part having its own hydraulic entrance for depending on the rotation position of the core selectively supplying hydraulic drive fluid to the hydraulic exits that are operationally coupled to the first hydraulic drive cylinder and the second hydraulic drive cylinder, and a second part hydraulically separated within the rotor valve from the first part, which second part has its own hydraulic entrance for depending on the rotation position of the core selectively supplying hydraulic drive fluid to the hydraulic exits that are operationally coupled to the third hydraulic drive cylinder, the fourth hydraulic drive cylinder, the fifth hydraulic drive cylinder and the sixth hydraulic drive cylinder.
With the first and second part the rotor valve has two separated circuits, as a result of which the first part can be dimensioned for the passing-through of hydraulic drive fluid for the power intensive compression strokes and the second part can be dimensioned for opening and closing the valves. Moreover the thrusting fluid flows for opening and closing the valves do not influence the separately supplied fluid flow for actuation of the compression strokes, as a result of which a smooth and therefore low-pulse or pulse-free outflow of slurry from the slurry outlet can be achieved.
In one embodiment thereof the rotor valve is provided with a third part preferably having its own hydraulic entrance for depending on the rotation position of the core selectively supplying hydraulic drive fluid to hydraulic exits which outside of the rotor valve are operationally coupled to the bottom sides of the first hydraulic drive cylinder and the second hydraulic drive cylinder or to the hydraulic exits that are operationally coupled to the bottom sides of the first hydraulic drive cylinder and the second hydraulic drive cylinder. The third part can supply hydraulic drive fluid for the first hydraulic drive cylinder and the second hydraulic drive cylinder at a different flow rate than required for the actual compression stroke. The third part can be advantageously dimensioned thereto with respect to the first part.
In a particular embodiment thereof the third part is adjusted to the first part for prior to selectively supplying hydraulic drive fluid to the first hydraulic drive cylinder or the second hydraulic drive cylinder, supplying a smaller quantity of hydraulic drive fluid to the first or second hydraulic drive cylinder when the inlet piece and the outlet piece thereof have been kept closed by the second part. In that way the slurry column can be pressurised in a pump cylinder that is kept closed, even prior to it being pushed to the slurry outlet via the outlet piece. Said pre-control pressure in the column can then be chosen to be equal to the prevailing pressure in the slurry outlet in order to obtain a pulse-free transition in the joining slurry flows.
In one embodiment the slurry pump is furthermore provided with a drive for rotation of the core at a substantially constant rotational speed over the several continuous revolutions. The drive preferably comprises a hydraulically driven motor, so that it can be driven by the hydraulic drive pump.
In one embodiment the hydraulically driven motor is hydraulically placed in series between the hydraulic drive pump and the hydraulic entrance of the first part of the rotor valve. In that way it can be achieved that the pumping speed of the slurry pump while operative can be increased or lowered by the supply of hydraulic drive fluid to the hydraulically driven motor as a result immediately also increasing or lowering the supply of hydraulic drive fluid to the first part. The second part and the third part, if present, are not subjected to changes, as a result of which the flow rates required for the control of the valves and the pre-control stroke, respectively, do not change, which is not necessary either.
In one embodiment the exits for the first hydraulic drive cylinder and the second hydraulic drive cylinder are directly connected to the bottom sides of the first hydraulic drive cylinder and the second hydraulic drive cylinder, so that they are directly controlled from the rotor valve.
In one embodiment the third hydraulic drive cylinder, the fourth hydraulic drive cylinder, the fifth hydraulic drive cylinder and the sixth hydraulic drive cylinder, via their own hydraulic switch or air valve block are connected to the hydraulic pump, wherein the hydraulic switches are coupled to the hydraulic exits for controlling the hydraulic switches.
In one embodiment the first pump cylinder and the second pump cylinder are fixedly positioned on the frame.
In one embodiment the casing of the rotor valve is retained on the frame.
The aspects and measures described in this description and the claims of the application and/or shown in the drawings of this application may where possible also be used individually. Said individual aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects that are described per se in the sub claims.

SHORT DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached schematic drawings, in which:

figure 1 shows an isometric front view of a pump with a rotor valve according to the invention;
figure 2 shows an isometric rear view of the pump with the rotor valve according to figure 1;
figure 3 shows a top view of the pump with the rotor valve according to figure 1;
figure 4 shows a cross-section of the rotor valve of the pump according to figure 1;
figures 5A-H show cross-sections VA-VH of the rotor valve according to figure 4;
figure 6 shows a schematic view of hydraulics of the pump according to figure 1;
figures 7A-F show a schematic view of the hydraulic operation of the pump according to figure 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Figures 1-3 show a pump 1 for pumping construction slurries for poured floors. Construction slurries are understood to mean mixtures according to lime and/or cement-tied recipes, such as cement mortar, concrete mortar containing hard pebbles, and Anhydrite.
The pump 1 is provided with a steady frame 2, a hopper 3 borne by the frame 2 for receiving the construction slurry and a first pump cylinder 4 and a second pump cylinder 5 that are attached parallel to each other underneath the hopper 3. The pump 1 is provided with a distribution line 30 connected to the hopper 3 for the supply of the construction slurry to a first inlet piece 40 and a second inlet piece 50. The first and second inlet piece 40, 50, respectively, are in fluid connection with the inside of the first and second pump cylinder 4, 5, respectively. The pump 1 is provided with a first outlet piece 41 and a second outlet piece 51 which on the one side are in fluid connection with the inside of the first and second pump cylinder 4, 5, respectively, and which on the other side are connected to a joint construction slurry line 10 having an outlet to which a flexible discharge hose 11 is connected.
The pump 1 is provided with a first and a second hydraulic drive cylinder 46, 56 that are positioned in line with the pump cylinders 4, 5. In said drive cylinders 46, 56 pistons 13 are provided that have drive rods 47 coupled thereto, wherein the drive rods 47 are each coupled to a displacer 17 in the pump cylinders 4, 5.
Above the inlet pieces 40, 50 and outlet pieces 41, 51 a hydraulic third, fourth, fifth and sixth drive cylinder 48, 49, 58, 59 are positioned. The inside work is schematically shown in figure 6. In said drive cylinders 48, 49, 58, 59 pistons 60 are provided with drive rods 61 coupled thereto, wherein the drive rods 61 are coupled to a first and a second inlet valve 42, 52 that are movable within the inlet pieces 40, 50 and a first and a second outlet valve 43, 53 that are movable within the outlet pieces 41, 51. By means of the inlet valves 42, 52 and the outlet valves 43, 53 the access to the inside of the pump cylinders 4, 5 can be closed off and cleared.
The pump 1 is provided with a control part 8 having several flexible hydraulic lines for actuating the hydraulic drive cylinders 46, 56, 48, 49, 58, 59. For the sake of clarity however, the flexible hydraulic lines have been left out of the figures 1-3.
The control part 8 comprises a rotor valve 81 as shown in detail in figures 4 and 5A-H. The rotor valve 81 is provided with a stationary positioned metal casing 85 and within it a metal core 86 that is rotatable about its longitudinal axis, wherein a perpetually continuous rotation over several revolutions of the core is ensured by means of a motor 83, driven with hydraulic drive fluid or oil, which motor via a stationary positioned reduction gearbox 84 is coupled to the core 86. After having driven the motor 83, the hydraulic fluid flows to the rotor valve 81.
The core 86 is provided with three separated groups of interconnected bores for depending on its rotation position changing the actuation of the hydraulic drive cylinders 46, 56, 48, 49, 58, 59.
The first group of interconnected bores comprises a first capped blind longitudinal bore 104 to which consecutively in longitudinal direction alternately straight opposite each other there are a first transverse bore 103, a second transverse bore 105, a third transverse bore 109 and a fourth transverse bore 120. The third transverse bore 109 ends in a first supply chamber 110. The second transverse bore 105 and the fourth transverse bore 120 end in a first and second compensation chamber 107, 121, respectively.
In the outer surface of the core 86, the first supply chamber 110 and the compensation chambers 107, 121 have a rectangular contour and each extend in circumferential direction over less than half the core 86, namely approximately one sixth of the outer circumference of the core 86. The joint projected surface of the compensation chambers 107, 121 equals the projected surface of the first supply chamber 110. Depending on the rotation position of the core 86, the compensation chambers 107, 121 are alternately opposite a first pressure chamber 106 or a second pressure chamber 124 in the casing 85. In the inner surface of the casing 85 the first and second pressure chamber 106, 124 have a rectangular contour.
The first and second pressure chamber 106, 124 both extend over approximately one third of the inner circumference of the casing 85 and are straight opposite each other in circumferential direction. The first transverse bore 103 is opposite a second supply chamber 102 in the casing 85 which chamber goes all round and thus is in continuous connection with a first external line coupling 101. Depending on the rotation position of the core 86 the first supply chamber 110 is alternately opposite a first discharge chamber 111 in the casing 85 that is in connection with a second external line coupling 108 or a second discharge chamber 122 in the casing 85 that is in connection with a third external line coupling 123. The first and second discharge chamber 111, 122 have a rectangular contour in the inner surface of the casing 85. The first and second discharge chamber 111, 122 both, equal to the first and second pressure chamber 106, 124, extend over approximately one third of the inner circumference of the casing 85 and are opposite each other in circumferential direction.
The second group of interconnected bores comprise a second capped blind longitudinal bore 204 to which consecutively in longitudinal direction alternately straight opposite each other there are a fifth transverse bore 208, a sixth transverse bore 211 and a seventh transverse bore 203. The fifth transverse bore 208 ends in a third supply chamber 209. The third supply chamber 209 has a rectangular contour in the outer surface of the core 86. The third supply chamber 209 describes an arch D of approximately 180 degrees and, depending on the rotation position of the core 86 for the length of the arch D, is alternately positioned opposite a third discharge chamber 220 in the casing 85 that is in connection with a fourth external line coupling 207 or a fourth discharge chamber 221 in the casing 85 that is in connection with a fifth external line coupling 222. The third and fourth discharge chamber 220, 221 in circumferential direction are straight opposite each other and both extend a few degrees over the circumference. The sixth transverse bore 211 ends in a fourth supply chamber 212. The fourth supply chamber 212 has a rectangular contour in the outer surface of the core 86. The fourth supply chamber 212 describes an arch E of approximately 120 degrees and, depending on the rotation position for the length of the arch E of the core, is alternately positioned opposite a fifth discharge chamber 223 in the casing 85 that is in connection with a sixth external line coupling 210 or a sixth discharge chamber 224 in the casing 85 that is in connection with a seventh external line coupling 225. The fifth and sixth discharge chamber 220, 221 equal to the third and fourth discharge chamber 220, 221 are straight opposite each other in circumferential direction and both extend a few degrees over the circumference. The seventh transverse bore 203 is opposite a fifth supply chamber 202 in the casing 85 that goes all round and which as a result is in continuous connection with an eighth external line coupling 201.
The third group of interconnected bores comprises a third capped blind longitudinal bore 304 to which consecutively in longitudinal direction an eighth transverse bore 305 and a ninth transverse bore 303 are oriented in the same direction towards the casing 85. The eighth transverse bore 305 depending on the rotation position of the core is alternately positioned opposite a seventh discharge chamber 320 in the casing 85 that is in connection with a ninth external line coupling 306 or an eighth discharge chamber 321 in the casing 85 that is in connection with a tenth external line coupling 322. The seventh and eighth discharge chamber 320, 321 equal to the third, fourth, fifth, and sixth discharge chamber 220, 221, 223, 224 are straight opposite each other in circumferential direction and both extend a few degrees over the circumference. The ninth transverse bore 303 is opposite a sixth supply chamber 302 in the casing 85 that goes all round and as a result is in continuous connection with an eleventh external line coupling 301.
Cross-section VA in figure 5A shows that the fully circumferential second supply chamber 102 due to the first external line coupling 101 is able to receive an ingoing hydraulic drive fluid flow T1 which is then passed through to the first longitudinal bore 104 via the first transverse bore 103.
Cross-sections VB in figure 5B show that the second transverse bore 105 and the fourth transverse bore 120 in the rotation position shown of the core 86 are able to receive a hydraulic drive fluid flow D in the compensation chambers 106 from the first longitudinal bore 104.
Cross-section VC in figure 5C shows that the first supply chamber 110 in the shown rotation position of the core 86 is opposite the first discharge chamber 111 for via the external second line coupling 108 discharging only an outgoing hydraulic drive fluid flow P2. In case of a further half a rotation of the core 86 in rotation direction R the first supply chamber 110 will be opposite the second discharge chamber 122 for via the external third line coupling 123 discharging only an outgoing hydraulic drive fluid flow P1. The discharge chambers 111, 122 due to their concave bottoms ensure a gradual build-up and run-down of hydraulic drive fluid flows P1 or P2 when the first discharge chamber 111 gets opposite the first or second discharge chamber 111, 122 and rotates away from them again, respectively.
The pressure of the hydraulic drive fluid against the inside of the compensation chambers 106, shown in figure 5B, provides counter pressure that counteracts radially oriented imbalance as a result of the outflow of hydraulic drive fluid to the first or second discharge chamber 111, 122 shown in figure 5C. The pressure chambers 106, 124 also due to their concave bottom shape ensure a gradual build-up and run-down of the counter pressure.
Cross-section VD in figure 5D shows that the third supply chamber 209 in the shown rotation position of the core 86 is opposite the fourth supply chamber 221 for via the fifth external line coupling 222 discharging an outgoing hydraulic drive fluid flow K3. In case of a further half a rotation of the core 86 in rotation direction R the third supply chamber 209 will be opposite the third discharge chamber 220 for via the fourth external line coupling 207 discharging an outgoing hydraulic drive fluid flow K1.
Cross-section VE in figure 5E shows that the fourth supply chamber 212 in the shown rotation position of the core 86 is opposite the fifth discharge chamber 223 for via the sixth external line coupling 210 discharging an outgoing hydraulic drive fluid flow K2. In case of a further half a rotation of the core 86 in rotation direction R the fourth supply chamber 212 will get opposite the sixth discharge chamber 224 for via the seventh external line coupling 225 discharging an outgoing hydraulic drive fluid flow K4.
Cross-section VF in figure 5F shows that the fully circumferential fifth supply chamber 202 in the shown rotation position of the core 86 is able to receive an ingoing hydraulic drive fluid flow T2 via the eight external line coupling 201 and is able to pass it through to the second longitudinal bore 204 via the seventh transverse bore 203.
Cross-section VG in figure 5G shows that the eighth transverse bore 305 in the shown rotation position of the core 86 is positioned blind in the middle between the seventh and eighth discharge chamber 320, 321. During rotation of the core 86 in rotation direction R the eighth transverse bore 305 will move opposite the seventh discharge chamber 320 for via the ninth external line coupling 306 discharging an outgoing hydraulic drive fluid flow V1. Half a revolution further therefrom the eight transverse bore 305 will be opposite the eighth discharge chamber 321 for via the tenth external line coupling 322 discharging an outgoing hydraulic drive fluid flow V2.
Cross-section VH in figure 5H shows that the fully circumferential sixth supply chamber 302 in the shown rotation position of the core 86 is able to receive an ingoing hydraulic drive fluid flow T3 via the eleventh external line coupling 301 and via the ninth transverse bore 303 is able to pass it through to the third transverse bore 304.
As shown in figure 6, the rotor valve 81, in accordance with the groups of bores as discussed above, can be functionally subdivided into a pressure part 100, a valve part 200 and a pre-control part 300 that are hydraulically separated from each other. The pump 1 is provided with a reservoir 87 for hydraulic drive fluid which via a hydraulic drive pump 88 is connected to a drive fluid distribution block 82 from which the hydraulic drive fluid flows T1, T2 and T3 with different flow rates are ensured via the lines 78-80 to the pressure part 100, the valve part 200 and the pre-control part 300 of the rotor valve 81. For rotation of the core 86, the motor 83 is in series with the pressure part 100 as a result of which hydraulic drive fluid flow T1 flows to the pressure part 100 via the motor 83. The drive fluid distribution block 82 also ensures hydraulic flows T4 and T5 to the first, second, third and fourth hydraulic drive cylinders 48, 49, 59, 58.
The motor 83 is hydraulically in series with the pressure part 100 of the rotor valve 81, as a result of which hydraulic drive fluid flow T1 leaving the motor 83 is directly passed to the pressure part 100 of the rotor valve 81. The quantity of hydraulic drive fluid which per revolution of the motor 83 flows through the motor 83 to the core 86, is at a predetermined ratio to the number drive rotations that the motor 83 transfers to the core 86. The ratio is such that the quantity of passed through hydraulic drive fluid equals the required hydraulic drive fluid for feeding the compression strokes from the core 86 during one full revolution of the core 86. If more hydraulic drive fluid is supplied, the motor 83 and the core 86 will rotate faster, however the quantity of hydraulic drive fluid passed through per revolution will remain the same.
From the pressure part 100 the outgoing hydraulic drive fluid flows P1, P2, are connected to the bottom sides of the first and second hydraulic drive cylinders 46, 56, respectively, via a first and a second flexible hydraulic drive line 70, 75, respectively. At the opposing upper sides the hydraulic drive cylinders 46, 56 are connected to one another by means of a balancing line 64. Via a third drive line 65, the balancing line 64 is connected to the drive fluid distribution block 82, with which continuously an extra hydraulic drive fluid flow T6 to the balancing line 64 can be ensured.
From the valve part 200 the outgoing hydraulic drive fluid flows K1-K4 are connected to a first, second, third and fourth hydraulic switch 13-16 via a first, second, third and fourth flexible hydraulic control line 91-91, in which a return switch 12 to be manually operated is arranged, in order to control the switches 13-16. At a short distance from the hydraulic switches 13-16 the flexible hydraulic control lines 91-94 are connected to a return line 25 to the hydraulic drive fluid reservoir 87 via a choke 24. The hydraulic switches 13-16 are connected to the drive fluid distribution block 82 and the hydraulic drive fluid reservoir 87, respectively, via a supply line 68 and a discharge line 69, for switching from the hydraulic drive fluid supply T4, T5 to a fourth, fifth, sixth and seventh drive line 71-74 and an eighth, ninth and tenth and eleventh drive line 171-174 of the third, fourth, fifth and sixth drive cylinders 48, 49, 59, 58. In case of a hydraulic drive fluid supply from the related control line 91-94 the hydraulic switches 13-16 are brought into a biassed inactive condition, wherein the hydraulic drive fluid is able to flow away via the choke 24. When the hydraulic drive fluid pressure from the related control line 91-94 drops away, the hydraulic switch 13-16 quickly returns to the inactive position.
As shown in figure 6, the pump 1 is provided with a fifth and sixth hydraulic switch 18 which is also controlled by the hydraulic drive fluid flows K2, K4 and arranged on the first and second drive line 70, 75, respectively, and which is able to open and close them. At a short distance from the hydraulic switches 18 the first and second drive lines 70, 75 are provided with a choke 27, wherein the hydraulic drive fluid is able to flow away to the hydraulic drive fluid reservoir 87 via the choke 27. The choke 27 counteracts that the fifth or sixth hydraulic switch 18, after the pressure in the hydraulic drive fluid flow K2, K4 drops away, remains actuated as a result of the hydraulic drive fluid still present in the line.
The return switch 12 to be manually operated is able to switch the hydraulic drive fluid flows K1, K2 one to the other and simultaneously switch the hydraulic drive fluid flows K3, K4 one to the other. In that way the operation of the inlet valves 42, 52 and the outlet valves 43, 53 per pump cylinder 4, 5 is simultaneously turned around.
From the pre-control part 300 the outgoing hydraulic drive fluid flows V1, V2 have been joined together with the outgoing hydraulic drive fluid flows P1 and P2, via a twelfth and a thirteenth flexible hydraulic drive line 76, 77.
Via a first overflow valve 97 acting as one-way valve, the first and second drive lines 70 and 75 are connected to an overflow exit that is arranged in the cylinder wall such that in the ultimate retracted bottom position of the piston 47, 57 it is in connection with the space at the drive rod side of the piston 47, 57. Each first overflow valve 97 blocks a fluid flow from the first and second drive line 70, 75 to the overflow exit, but allows an overflow of hydraulic drive fluid from the hydraulic cylinder 46, 56 to the first and second drive line 70, 75 above a set determined threshold value of the hydraulic drive fluid pressure.
Via second overflow valves 98 acting as one-way valves, the balancing line 64 is connected to overflow exits that are arranged such in the cylinder walls of the first and second pump cylinder 4, 5 that in the ultimate extended upper position of the piston 47, 57 they are in connection with the space at the side of the piston 47, 57 facing away from the drive rod. Each second overflow valve 98 blocks a fluid flow from the drive line 65 to the overflow exit, but allows an overflow of hydraulic drive fluid from the hydraulic cylinder 46, 56 to the drive line 65 above a set determined threshold value of the hydraulic drive fluid pressure.
The third drive line 65 is connected to an overflow line 66 via a one-way valve 28. The one-way valve 28 blocks a fluid flow from the third drive line 65 to the overflow line 66, but allows an overflow of hydraulic drive fluid from the third drive line 65 to the overflow line 66 above a set determined threshold value of the hydraulic drive fluid pressure. The overflow line 66 is connected to the reservoir 87.
Figures 7A-F in schematic consecutive moments show the operation of the pump 1 according to figures 1-6 during one full revolution of the core 86.
Prior to the situation shown in figure 7A the pump 1 is started up by actuating the hydraulic drive pump 88. The hydraulic drive pump 88 ensures hydraulic drive fluid flows to the system, which in a manner further to be described activate the pump cylinders 4, 5, the inlet valves 42, 52 and the outlet valves 43, 53. The drive fluid distribution block 82 ensures a dosed distribution of the supplied hydraulic drive fluid over hydraulic drive fluid flows T1-T5. Hydraulic drive fluid flow T1 is continuous, as a result of which the core is rotated in direction R at a constant rotational speed over several revolutions by the hydraulic motor 83. During said start-up process it may occur that the starting positions of the moving parts of the pump 1 do not yet correspond with the desired positions with respect to the control signals as imposed by the rotating core 86 in the rotor valve 81. In that case hydraulic drive fluid can be discharged while it is already abundantly present. Particularly, in case the first drive cylinder 46, 56 has reached the end of a compression stroke too soon, its overflow valve 98 can ensure an overflow of superfluous hydraulic drive fluid, until the supply of hydraulic drive fluid by the rotor valve 81 to the first or second drive cylinder 46, 56 has stopped. Said overflow ensures that the second cylinder 5 fully completes its piston stroke. The other way round, when the second cylinder 5 reaches the end of the piston stroke too soon, the overflow valve 97 allows an overflow of superfluous hydraulic drive fluid, so that the first cylinder 4 fully completes its compression stroke. The overflow predominantly takes place during the first revolutions during the start-up process of the pump 1 or when using the return switch 12.
Figure 7A shows the situation in which the displacer 17 of the first cylinder 4 has completed a compression stroke and is ready to make a piston stroke by being retracted in the direction of the first hydraulic drive cylinder 46. This situation corresponds with the rotor valve 81 in the rotation position as shown in figures 4 and 5A-H. Due to this rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K1 from the first control line 91 has been interrupted, as shown in figure 5D. Figure 7A shows that because of this the second hydraulic switch 14 is in the inactive position. The bottom side of the fourth hydraulic cylinder 49 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the first outlet valve 43 has closed off the passage in the first outlet piece 41.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K2 through the second control line 92 is continued, as shown in figure 5E, as a result of which the first hydraulic switch 13 is placed out of the inactive position. The drive rod side of the third hydraulic drive cylinder 48 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the first inlet valve 42 has ended the closing off of the passage in the first inlet piece 40.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K4 from the fourth control line 94 has been interrupted, as shown in figure 5E. Figure 7A shows that as a result of this the fourth hydraulic switch 16 is in the inactive position. The drive rod side of the fifth hydraulic drive cylinder 58 has been filled with hydraulic fluid from the hydraulic fluid distributor 82. As a result of this the second inlet valve 52 has closed off the passage in the second inlet piece 50.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K3 through the third control line 93 is continued, as shown in figure 5D, as a result of which third hydraulic switch 15 is placed out of the inactive position. Figure 7A shows that the bottom side of the sixth hydraulic drive cylinder 59 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the second outlet valve 53 has ended the closing off of the passage in the second outlet piece 51.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow P2 through the second drive line 75 is continued, as shown in figure 5C. Figure 7A shows that the bottom side of the second cylinder 5 has been filled with hydraulic fluid from the drive fluid distribution block 82. In its thrust motion the displacer 17 of the second cylinder 5 has as a result been partially moved in the direction of the second outlet piece 51. The second cylinder 5 that is already filled with slurry presses the slurry to the outgoing construction slurry line 11 according to construction slurry flows B6, B7.
Figure 7B shows the situation following the one of figure 7A, in which the core 86 of the rotor valve 81 has rotated onwards. In said rotation position the hydraulic drive fluid flow P2 through the second drive line 75 is still continued as a result of which the displacer 17 of the second cylinder 5 is further in its compression stroke. The hydraulic drive fluid that has been pushed out of the drive rod side of the second hydraulic drive cylinder 56, has been siphoned over via the balancing line 64 to the drive rod side of the first hydraulic drive cylinder 46. With respect to figure 7A the displacer 17 of the first cylinder 4 has as a result been retracted further in the direction of the first hydraulic drive cylinder 46. From the hydraulic fluid distributor 82 a constant extra hydraulic drive fluid flow T6 has been supplied through the third drive line 65, so that the piston stroke of the first cylinder 4 takes place more quickly than the compression stroke of the second cylinder 5 and is also completed sooner. From the distribution line 30 of the hopper 3 a construction slurry flow B1, B3 has been set into motion that is sucked into the first cylinder 4. Via the construction slurry flows B6, B7, the displacer 17 of the second cylinder 5 has pushed a portion of the construction slurry received in the second cylinder 5 to the outgoing construction slurry line 11 at a constant flow rate.
Figure 7C shows the situation following the one in Figure 7B, wherein the core 86 of the rotor valve 81 has rotated onwards and the displacer 17 of the second cylinder 5 has almost completed a full compression stroke. Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K2 through the second control line 92 from the core 86 has been interrupted, as a result of which the first hydraulic switch 13 has returned to the inactive position. The bottom side of the third hydraulic drive cylinder 48 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result the first inlet valve 42 has closed off the first inlet piece 40.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow V1 is continued. The bottom side of the first hydraulic drive cylinder 46 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result the displacer 17 has moved in the first cylinder 4 (this is shown in a highly exaggerated manner), because of which the volume of the first pump cylinder 4 is fractionally reduced whereas the construction slurry has not been able to escape through the inlet or outlet piece 40, 41. As a result the construction slurry in the first pump cylinder 4 is under a pre-control pressure that equals the pressure prevailing in the outgoing slurry flow B7.
Figure 7D shows the situation following the one in figure 7C, wherein the core 86 of the rotor valve 81 has rotated onwards. Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K1 from the first control line 91 is continued, as a result of which the second hydraulic switch 14 is placed out of the inactive position. The drive rod side of the fourth hydraulic drive cylinder 49 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the first outlet valve 43 has ended the closing off of the passage in the first outlet piece 41. The first outlet piece 41 and the second outlet piece 51 are now both in flowing connection with the joint construction slurry line 10, in order to be able to take over the slurry flow B7 pushed outside under pressure by the compression stroke of the second cylinder 5, at the same already built-up pressure, prior to the second outlet piece 51 of the second cylinder 5 being closed off in a situation further to be described (figure 7E). The displacers 17 are moved simultaneously in the same direction. The pressure in the balancing line 64 becomes so great, that the one-way valve 28 allows a superfluous hydraulic drive fluid flow via the overflow line 66 to the hydraulic drive fluid reservoir 87.
The steps described above in figures 7A-D occur in a comparable manner in figures 7E-H. The core 86 has made half a rotation and rotates onwards, wherein the hydraulic drive fluid flows are switched such that in figures 7E-H the first cylinder 4 goes through the steps that the second cylinder 5 goes through in figure 7A-D and wherein in figures 7E-H the second cylinder 5 goes through the steps that the first cylinder 4 goes through in figures 7A-D.
Figure 7E shows the situation in which the displacer 17 of the second cylinder 5 has completed a compression stroke and is ready to make a piston stroke by being retracted in the direction of the second hydraulic drive cylinder 56. Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K3 from the third control line 93 has been interrupted. As a result of this the third hydraulic switch 15 is in the inactive position. The bottom side of the sixth hydraulic drive cylinder 59 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the second outlet valve 53 has closed off the passage in the second outlet piece 51.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K4 through the fourth control line 94 is continued, as a result of which the fourth hydraulic switch 16 is placed out of the inactive position. The drive rod side of the fifth hydraulic drive cylinder 58 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the second inlet valve 52 has ended the closing off of the passage in the second inlet piece 50.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K2 from the second control line 92 has been interrupted. As a result of this the first hydraulic switch 13 is in the inactive position. The drive rod side of the third hydraulic drive cylinder 48 has been filled with hydraulic fluid from the hydraulic fluid distributor 82. As a result of this the first inlet valve 42 has closed off the passage in the first inlet piece 40.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K1 through the first control line 91 is continued, as a result of which the second hydraulic switch 14 is placed out of the inactive position. The bottom side of the fourth hydraulic drive cylinder 49 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the first outlet valve 43 has ended the closing off of the passage in the first outlet piece 41.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow P1 through the first drive line 70 is continued. The bottom side of the first cylinder 4 has been filled with hydraulic fluid from the drive fluid distribution block 82. In its thrust motion the displacer 17 of the first cylinder 4 has as a result been partially moved in the direction of the first outlet piece 41. The first cylinder 4 that is already filled with slurry presses the slurry to the outgoing construction slurry line 11 according to construction slurry flows B4, B7.
Figure 7F shows the situation following the one of figure 7E, in which the core 86 of the rotor valve 81 has rotated onwards. In said rotation position the hydraulic drive fluid flow P1 through the second drive line 70 is still continued as a result of which the displacer 17 of the first cylinder 4 is further in its compression stroke. The hydraulic drive fluid that has been pushed out of the drive rod side of the first hydraulic drive cylinder 46, has been siphoned over via the balancing line 64 to the drive rod side of the second hydraulic drive cylinder 56. With respect to figure 7E the displacer 17 of the second cylinder 5 has as a result been retracted further in the direction of the second hydraulic drive cylinder 56. From the hydraulic fluid distributor 82 a constant extra hydraulic drive fluid flow T6 has been supplied through the third drive line 65, so that the piston stroke of the second cylinder 5 takes place more quickly than the compression stroke of the first cylinder 4 and is also completed sooner. From the distribution line 30 of the hopper 3 a construction slurry flow B2, B5 has been set into motion that is sucked into the second cylinder 5. Via the construction slurry flows B4, B7, the displacer 17 of the first cylinder 4 has pushed a portion of the construction slurry received in the first cylinder 4 to the outgoing construction slurry line 11 at a constant flow rate.
Figure 7G shows the situation following the one in Figure 7F, wherein the core 86 of the rotor valve 81 has rotated onwards and the displacer 17 of the first cylinder 4 has almost completed a full compression stroke. Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K4 through the fourth control line 94 from the core 86 has been interrupted, as a result of which the fourth hydraulic switch 16 has returned to the inactive position. The bottom side of the fifth hydraulic drive cylinder 58 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result the second inlet valve 52 has closed off the second inlet piece 50.
Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow V2 is continued. The bottom side of the second hydraulic drive cylinder 56 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result the displacer 17 has moved in the second cylinder 5 (this is shown in a highly exaggerated manner), because of which the volume of the second cylinder 5 is fractionally reduced whereas the construction slurry has not been able to escape through the inlet or outlet piece 50, 51. As a result of this the construction slurry in the second pump cylinder 5 is under a pre-control pressure that equals the pressure prevailing in the outgoing slurry flow B7.
Figure 7H shows the situation following the one in figure 7G, wherein the core 86 of the rotor valve 81 has rotated onwards. Due to the rotation position of the core 86 of the rotor valve 81 the hydraulic drive fluid flow K3 from the third control line 93 is continued, as a result of which the third hydraulic switch 15 is placed out of the inactive position. The drive rod side of the sixth hydraulic drive cylinder 59 has been filled with hydraulic fluid from the drive fluid distribution block 82. As a result of this the second outlet valve 53 has ended the closing off of the passage in the second outlet piece 51. The second outlet piece 51 and the first outlet piece 41 are now both in flowing connection with the joint construction slurry line 10, in order to be able to take over the slurry flow B7 pushed outside under pressure by the compression stroke of the first cylinder 4, at the same already built-up pressure, prior to the first outlet piece 41 of the first cylinder 4 being closed off in an already described situation (figure 7A). The displacers 17 are moved simultaneously in the same direction. The pressure in the balancing line 64 becomes so great, that the one-way valve 28 allows a superfluous hydraulic drive fluid flow via the overflow line 66 to the hydraulic drive fluid reservoir 87.
As shown in figure 5E, during a revolution of the core 86 the circumferential recess 212 with the arch E of 120 degrees is alternately in flowing contact with the first and fourth hydraulic switches 13, 16 shown in figure 6 for from the rotor valve 81 alternately controlling the inlet valves 42, 52 in the inlet pieces 40, 50. As shown in figure 5D, during a revolution of the core 86 the circumferential recess 209 with the arch D of 180 degrees is alternately in flowing contact with the second and third hydraulic switches 14, 15 shown in figure 6 for from the rotor valve 81 alternately controlling the outlet valves 43, 53 in the outlet pieces 41, 51. As a result the inlet pieces 40, 50 are controlled from the rotor valve 81, for in accordance with piston strokes that are shorter than the compression strokes, being open shorter than the outlet pieces 41, 51.
The steps described above and shown in figures 7A-H take place within one full revolution of the core 86 within the rotor valve 81. The steps are aimed at the first and second cylinder 4, 5, that mutually alternate making a compression stroke at a constant speed or a piston stroke, taking over each other's compression or piston stroke, without generating an appreciable pulse or short standstill in the outgoing construction slurry flow B7 during the compression stroke. As shown in figures 4, 5A-H, 7A-H the mutual synchronisation is controlled from the rotor valve 81 by the hydraulic drive fluid flows P1, P2, K1-4, V1 and V2 depending on the rotation position of the core 86, wherein the speeds and intervals are incorporated in the mutual relation between the outflow channels 109, 208, 211, 305, the supply chambers 102, 110, 209, 212, 202, 302, the discharge chambers 220, 223, 224, 320, 321, the partially circumferential slots 209, 212 and the partially circumferential recesses 106, 111 in the core 86 and the line couplings 108, 123, 207, 222, 210, 225, 306, 322 in the casing 85. The hydraulic drive fluid flows P1, P2, K1-4, V1 and V2 are only continued from the core 86 when the related supply chambers 102, 110, 209, 212, 202, 302, and the related discharge chambers 220, 223, 224, 320, 321 are in flowing connection with each other. When this is not the case there is question of an interruption of the hydraulic drive fluid flow P1, P2, K1-4, V1 and V2. In that way, depending on the rotation position of the core 86, the rotor valve 81 switches between the various hydraulic drive fluid flows P1, P2, K1-4, V1, V2, wherein dimensioning and position of the said elements is selected accurately in order to achieve an optimal operation of the pump 1.
In an alternative embodiment the motor 83 and the core 86 are provided with hydraulic fluid by separate hydraulic fluid flows, wherein the required quantities are controlled by means of flow meters to the rotor valve 81 and the motor 83 and electronic switches switching on the basis thereof for setting the flow rate to the motor or the rotor valve.
It will be clear that the above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention, which is defined by the appended claims.

Claims

Slurry pump (1), particularly for pumping abrasive slurries or construction slurries, comprising a frame (2), a slurry supply container (3), a first pump cylinder (4) and a second pump cylinder (5) on the frame (2), a first hydraulic drive cylinder (46) and a second hydraulic drive cylinder (56) that are both provided with a piston (45) and a piston rod (47, 57) at is connected to a slurry displacer (17) in the first pump cylinder (4) and second pump cylinder (5), respectively, for moving the slurry displacer (17) through the pump cylinder (4, 5), a slurry outlet (10), a first inlet piece (40) and a second inlet piece (50) that are situated in a flow-through connection between the slurry supply container (3) on the one hand and the first pump cylinder (4) and the second pump cylinder (5), respectively, on the other hand, a first outlet piece (41) and a second outlet piece (51) that are situated in a flow-through connection between the first pump cylinder (4) and second pump cylinder (5) respectively, on the one hand and the slurry outle (10) on the other hand, a third hydraulic drive cylinder (48), a fourth hydraulic drive cylinder (49), a fifth hydraulic drive cylinder (58) and a sixth hydraulic drive cylinder (59) that have all been provided with a piston (60) and a piston rod (61) that is connected to a valve (42, 43, 52, 53) situated in the first inlet piece (40), first outlet piece (41) second inlet piece (50) and second outlet respectively (51), for depending on its position closing off or releasing the flow-through connection, characterised by a rotor valve (81) for controlling the pump (1) and a hydraulic drive pump (88) that is connected to the rotor valve (81), wherein the rotor valve is provided with a casing (85) having several passage openings (111, 122, 220, 221, 223, 224) at the inside that connect to hydraulic exits at the outside and a core (86) which within the casing is rotatable about its axis over several continuing revolutions, the core having supply openings (110, 209, 212) in its circumferential surface for depending on its rotation position selectively supplying hydraulic drive fluid to the passage openings, wherein the hydraulic drive cylinders (46, 56, 48, 49, 58, 59) are operationally coupled to the hydraulic exits for actuation of the hydraulic drive cylinders (46, 56, 48, 49, 58, 59) according to a repetitive pump cycle controlled by the rotation of the core.
Slurry pump (1) according to claim 1, wherein the hydraulic drive cylinders (46, 56, 48, 49, 58, 59) each are operationally coupled to their own hydraulic exit (108, 123, 207, 210, 222, 225) of the rotor valve (81).
Slurry pump (1) according to claim 1 or 2, wherein the inside of the first drive cylinder (46) and the second hydraulic drive cylinder (56) is divided by the pistons (95) into a piston rod side and a bottom side, wherein the hydraulic exit (123) for the first drive cylinder and the hydraulic exit (108) for the second hydraulic drive cylinder are hydraulically connected to the bottom sides of the first hydraulic drive cylinder and second hydraulic drive cylinder, respectively.
Slurry pump (1) according to claim 3, wherein the piston rod sides of the first hydraulic drive cylinder (46) and the second hydraulic drive cylinder (56) are connected to one another with a balancing line (64), wherein preferably also via a one-way valve (98) opening towards the balancing line, the balancing line connects to a part of the inside of the hydraulic drive cylinder (46, 56) situated in the end range of a compression stroke of the slurry displacer at the bottom side of the piston.
Slurry pump (1) according to claim 4, wherein outside of the rotor valve, the hydraulic drive pump (88) is connected to the balancing line (64) for a continuous supply of hydraulic drive fluid to the balancing line.
Slurry pump (1) according to any one of the claims 3-5, wherein the connections to the bottom sides of the first hydraulic drive cylinder (46) and the second hydraulic drive cylinder (56) also via a one-way valve (97) opening towards the exit of the rotor valve (81) connect to a part of the inside of he hydraulic drive cylinder situated in the starting range of a compression stroke of the slurry displacer at the piston rod side of the piston.
Slurry pump (1) according to any one of the preceding claims, wherein the rotor valve (81) is provided with a first part having its own hydraulic entrance for depending on the rotation position of the core selectively supplying hydraulic drive fluid to the hydraulic exits that are operationally coupled to the first hydraulic drive cylinder (46) and the second hydraulic drive cylinder (56), and a second part hydraulically separated within the rotor valve from the first part, which second part has its own hydraulic entrance for depending on the rotation position of the core selectively supplying hydraulic drive fluid to the hydraulic exits that are operationally coupled to the third hydraulic drive cylinder (48), the fourth hydraulic drive cylinder (49), the fifth hydraulic drive cylinder (58) and the sixth hydraulic drive cylinder (59).
Slurry pump (1) according to claim 7, wherein the rotor valve (81) is provided with a third part preferably having its own hydraulic entrance for depending on the rotation position of the core selectively supplying hydraulic drive fluid to hydraulic exits which beyond the rotor valve are operationally coupled to the bottom sides of the first hydraulic drive cylinder (46) and the second hydraulic drive cylinder (56) or to the hydraulic exits that are operationally coupled to the bottom sides of the first hydraulic drive cylinder (46) and the second hydraulic drive cylinder (56).
Slurry pump (1) according to claim 8, wherein the third part is adjusted to the first part for prior to selectively supplying hydraulic drive fluid to the first hydraulic drive cylinder (46) or the second hydraulic drive cylinder (56), supplying a smaller quantity of hydraulic drive fluid to the first or second hydraulic drive cylinder when the inlet piece (40, 50) and the outlet piece (41, 51) thereof have been kept closed by the second part.
Slurry pump (10) according to any one of the preceding claims, furthermore provided with a drive (83) for rotation of the core at a substantially constant rotational speed over the several continuous revolutions, wherein the drive (83) preferably comprises a hydraulically driven motor.
Slurry pump (1) according to claim 7 and 10, wherein the hydraulically driven motor is hydraulically placed in series between the hydraulic drive pump (88) and the hydraulic entrance of the first part of the rotor valve (81).
Slurry pump (1) according to any one of the preceding claims, wherein the exits (123, 108) for the first hydraulic drive cylinder (46) and the second hydraulic drive cylinder (56) are directly connected to the bottom sides of the first hydraulic drive cylinder and the second hydraulic drive cylinder.
Slurry pump (1) according to any one of the preceding claims, wherein the third hydraulic drive cylinder (48), the fourth hydraulic drive cylinder (49), the fifth hydraulic drive cylinder (58) and the sixth hydraulic drive cylinder (59) via their own hydraulic switch or air valve block (13, 14, 15, 16) are connected to the hydraulic pump, wherein the hydraulic switches are coupled to the hydraulic exits (207, 210, 222, 225) for controlling the hydraulic switches.
Slurry pump (1) according to any one of the preceding claims, wherein the first pump cylinder (4) and the second pump cylinder (5) are fixedly positioned on the frame (2).
Slurry pump (1) according to any one of the preceding claims, wherein the casing (85) of the rotor valve (81) is retained on the frame (2).