EP1843040A2 - Method for operating an oscillating displacement pump and oscillating displacement pump - Google Patents

Abstract

Method involves accomplishment of pressure compensation between the individual pump chambers (1,2), during the pre-compressions phase and prevention of pressure compensation between the individual pump chambers, during the subsequent conveying stroke. The two pump chambers are provided for each liquid and movable displacement body (4,5). One of the displacement bodies absorbs liquid during the actual conveying phase of the other displacement body. An independent claim is included for the oscillating positive-displacement pump.

Description

The invention relates to a method for operating an oscillating positive displacement pump for the simultaneous pulsation of several liquids, with at least two pump chambers for each liquid and movable displacers therein, of which each sucks a displacer during the actual delivery phase of the other displacer liquid, at the end of Suction stroke reverses its direction of movement, precompresses the sucked into the associated pump chamber liquid in a Vorkompressionsphase and comes to a standstill upon reaching a predetermined Vorkompressionsdruckes and so long at standstill until the other displacer has finished its liquid promotion and then to this promotion then in turn with the promotion starts. Moreover, the invention relates to an oscillating positive displacement pump for the simultaneous pulsation of several liquids, with at least two pump chambers for each liquid and movable displacers therein, each of which a displacer during the actual delivery phase of the other displacer liquid sucks, at the end of the suction stroke its direction of movement reversed, precompresses the sucked into a corresponding pump chamber liquid in a Vorkompressionsphase and upon reaching a predeterminable pre-compression pressure comes to a standstill and remains at a standstill until the other displacer has finished its fluid delivery and then subsequently to this promotion in turn begins with the promotion.

In known such pumps, the displacer for the individual pump chambers are rigidly connected to each other and have a common drive, usually in the form of a hydraulic cylinder.

Extraordinary pulsation poverty without the use of so-called pulsation dampers is achieved by oscillating positive displacement pumps with two displacers for each liquid, of which one displacer sucks liquid during the actual delivery phase of the other displacer at the end of the suction stroke reverses its direction of movement sucked into the pump chamber Pre-compressed liquid and comes to a standstill upon reaching a predetermined pressure from the system and remains as long as at standstill until the other displacer has finished its fluid delivery and then to this promotion the resting at the end of the pre-compression phase displacer begins its promotion.

The applied in the hydraulic drive cylinder hydraulic pressure is in such pumps, for example, by a control device according to DE 197 27 623 C1 as a function of the pressure of the currently pumping side just so regulated that it always remains at a safe distance below the pressure of the currently pumping side, so that liquid outlet valves of the pump chambers can not open due to the higher in the liquid line to the consumer pressure prevailing.

With such pumps, different precompression pressures generally occur in both delivery cylinders until one of the output valves is opened, with different precompression pressures usually also occurring from delivery stroke to delivery stroke. That once both precompression pressures are equal, is rather a rare coincidence. Dependent are the differences in the pre-compression pressures of different Pumpemkammerfüllungsgraden, viscosity differences, different tightness at the valves, differences in the compressibility of the two liquids to be pumped, which can vary greatly, for example, even by individual air bubbles from hub to hub, as well as different elasticities of the components ,

At the end of the precompression stroke, the hydraulic piston force of the drive cylinder is in equilibrium with the sum of both axial forces on the displacers. The sum of both displacer forces (precompression pressure times area) is always the same, i. the shortfall in precompression force on the one displacer adds to the other displacer. So there is a double effect

Of great influence on the difference of the precompression pressures is the area ratio of the two displacers. The larger the area difference, the faster and so on, the precompression pressure in the displacer with the small area increases because of the small pump chamber volume via the Vorkompressionsdruck the pump chamber with the large-area displacer.

• je größer der Flächenunterschied der Verdränger ist,
• je dichter ein Saugventil der kleineren Pumpenkammer ist,
• je weniger dicht ein Saugventil der größeren Pumpenkammer ist,
• je schneller sich das Saugventil der kleineren Pumpenkammer schließt,
• je langsamer sich das Saugventil der größeren Pumpenkammer schließt,
• je größer der Füllungsgrad der kleineren Pumpenkammer ist,
• je kleiner der Füllungsgrad der größeren Pumpenkammer ist,
• je kleiner das Volumen der kleineren Pumpenkammer ist,
• je größer das Volumen der größeren Pumpenkammer ist,
• je weniger kompressibel die Flüssigkeit im der kleineren Pumpenkammer ist und
• je kompressibler die Flüssigkeit in der größeren Pumpenkammer ist.

The possible pressure difference is the greater

• the larger the area difference of the displacer,
• the closer a suction valve of the smaller pump chamber is,
• the less dense a suction valve of the larger pump chamber is,
• the faster the suction valve of the smaller pump chamber closes,
• the slower the suction valve of the larger pump chamber closes,
• the greater the degree of filling of the smaller pump chamber,
• the smaller the degree of filling of the larger pump chamber,
• the smaller the volume of the smaller pump chamber,
• the larger the volume of the larger pump chamber,
• the less compressible the liquid is in the smaller pump chamber and
• the more compressible the fluid is in the larger pump chamber.

It is clear from the above that the larger the displacement surface difference and the more different the two fluids to be delivered, the less can statements about the magnitude of the differences in the precompression pressures be made. For the sake of simplicity, from now on only different degrees of filling should be used.

If, for example, insufficient filling or a leaking suction valve is achieved at a displacement ratio of 1: 1 in one of the two pump chambers, the precompression pressure in the other cylinder increases to twice the pressure as is set with a uniform distribution would. Is at a Verdrängerflächenverhältnis, for example, 49: 1 in the cylinder with the pre-compression does not reach the large displacement, in the other cylinder the pressure rises to 49 times the pressure.

If the unevenly pre-compressed pump chamber fillings on one side of the pump at the beginning of the delivery stroke with lines to the consumer, e.g. a spray gun to be connected, the promotion of the two liquids begins unevenly and staggered. The delivery cylinder with the opposite of a consumer line pressure increased pressure is at its pressure release to consumer pressure jerky a corresponding amount of liquid in addition to the target amount in the consumer line. The other delivery cylinder with the opposite of the consumer pressure lower Vorkompressionsdruck must first be further compressed to consumer pressure before material is pressed into the consumer line. To do this, the displacement stroke, i. Time, necessary. While one pump chamber, based on one pump side, starts with excess delivery, the delivery from the other pump chamber begins too late, so that the consumer lacks fluid from the supply cylinder, which is too low for a short time.

For the present invention, therefore, has the object to eliminate these disadvantages of flow irregularities of the previous methods and devices and to provide a method and an apparatus of the type specified above, which ensure a constantly uniform delivery of the liquids to be delivered.

To solve the first part of the problem, a method of the type mentioned is proposed, which is characterized in that during the Vorkompressionsphase a pressure equalization between the individual pump chambers is performed and during the subsequent delivery stroke pressure equalization between the individual pump chambers is prevented.

With the method according to the invention, it is advantageously achieved that different pre-compression pressures are avoided and that the liquid delivery at the beginning of the delivery stroke from all pump chambers starts and is maintained simultaneously at sizes corresponding to the displacement cross-sections.

Embodiments of the method are specified in claims 2 to 5.

A first embodiment provides that for each liquid to be conveyed, rigidly connected to a single drive piston pistons transmit their power via a fluid to each of the piston associated displacer, wherein fluid spaces between the individual pistons and the associated displacer during the Vorkompressionsphase with each other connected and decoupled from each other during the delivery. The fluid spaces associated with the displacers are thus interconnected during the precompression phase, so that the displacers can move relative to one another until the pressure equality in the pump chambers is reached. During the delivery stroke, however, the connection of the fluid spaces is interrupted, so that then no pressure compensation can take place and the displacer perform the delivery stroke as rigidly coupled together.

In another embodiment of the invention, it is proposed that the pressure compensation be effected by displacement of operatively connected, exposed to the vorzukomprimierenden liquids, lockable piston becomes. Preferably, for this purpose, a displaceable in a housing, the housing is used in two chambers dividing balance piston with two equal piston surfaces, each chamber is connected to one of the pump chambers. When the pressure difference between the pump chambers, the compensation piston moves under the influence of the larger pressure in the direction of the pump chamber with the smaller pressure until the pressure difference has reduced to zero. In at least one of two lines between each of the pump chamber and the associated chamber of the pressure compensation device, a shut-off device should be present, which is opened during the Vorkompressionsphase for pressure equalization between the pump chambers and closed during the delivery stroke, so that the displacer connected the delivery stroke as rigid To run. During the suction stroke and at the same time opened shut-off device, the compensating piston should be forced into its central position by at least one centering spring, preferably two centering springs. Thus, the entire pressure equalization capacity of the pressure compensation device is available again for the subsequent precompression phase. Instead of a two-sided acted upon by the two liquids to be delivered compensating piston and two unilaterally acted upon by the liquids balance piston can be used, which are operatively connected to each other via a lever assembly.

According to a preferred embodiment, in particular for cases in which the displacers have extremely different cross sections, it is provided that the displacers are driven independently of each other during the precompression phase, come to a standstill independently upon reaching the desired Vorkompressionsdruckes and coupled together during the delivery stroke become. In other words, therefore, the small-area displacer should be rigidly coupled to the large-area displacer during the delivery stroke. During the precompression phase, the small-area displacer should be displaceable relative to the large-area displacer relative thereto and preferably generate approximately the same precompression end pressure in the fluid enclosed in the associated pump chamber by a hydraulic cylinder of corresponding size in the associated pump chamber as in the fluid in the pump chamber with the large-area displacer ,

The small-area displacer is expediently brought into a zero position with the aid of a cylinder, preferably a pneumatic cylinder, during the suction stroke, from which the full intended pressure compensation capacity is available in both directions for the subsequent precompression phase.

In another preferred embodiment, the invention proposes that the precompression is performed by the second and each further displacer associated with a pump side, each acting on the same liquid to be delivered, hydraulically decoupled driven, during the delivery stroke lockable Vorkompressionsverdränger. In contrast to the previously stated embodiment, therefore, instead of the one small-area displacer, two displacers are to be used which act on the same amount of liquid trapped in the delivery cylinder. However, the one displacer should always be rigidly coupled to the large-area displacer and take over the liquid conveying function, while the other small-area displacer should take over the pressure equalization during the precompression phase. This further small-area displacer should therefore be opposite the other small-area displacer relatively displaceable and be connected to a cylinder, preferably hydraulic cylinder, corresponding size, which generates in the trapped liquid in about the same Vorkompressionsenddruck as in the pump chamber with the large-area displacer. During the delivery stroke, the displaceability of this further small-area displacer should be eliminated, for example by closing a shut-off valve arranged in a hydraulic line to the associated hydraulic cylinder.

Also in this variant, the further small-area displacer is expediently brought into a zero position during the suction stroke, from which the full intended movement possibility is available in both directions for the subsequent precompression phase.

The solution of the second part of the object succeeds according to the invention with an oscillating positive displacement pump of the type mentioned, which is characterized by during the Vorkompressionsphase a pressure equalization between the individual pump chambers and performing during the subsequent delivery stroke a pressure equalization between the individual pump chambers preventing agent.

Advantageous embodiments and further developments of the positive displacement pump according to the invention are specified in claims 7 to 15.

Fig. 1

eine oszillierende Verdrängerpumpe in einer ersten Ausgestaltung, bei der zwei mit einem hydraulischen Antriebskolben starr verbundene weitere Hydraulikkolben ihre Kraft über ein eingeschlossenes Fluid auf Verdränger übertragen,

Fig. 2

die Verdrängerpumpe in einer Ausgestaltung mit einer von den in zwei Pumpenkammern eingeschlossenen Flüssigkeiten beaufschlagten Druckausgleichsvorrichtung,

Fig. 3

die Verdrängerpumpe in einer Ausgestaltung, bei der während einer Vorkompressionsphase beide Verdränger jeder Pumpenseite unabhängig voneinander die in den Pumpenkammern eingeschlossenen Flüssigkeiten auf Vorkompressionsenddruck bringen,

Fig. 4 bis 6

jeweils einen Ausschnitt aus Fig. 3 mit dem Pumpenteil mit kleinflächigem Verdränger in verschiedenen Positionen,

Fig. 7

die Verdrängerpumpe in einer Ausgestaltung, bei der während der Vorkompressionsphase die eine Flüssigkeit durch ihren zugehörigen Verdränger und die andere Flüssigkeit durch einen bei einem Förderhub nicht mitlaufenden, eigens für eine Vorkompression vorgesehenen weiteren Verdränger auf Vorkompressionsenddruck gebracht wird, und

Fig. 8 bis 10

jeweils einen Ausschnitt aus Fig. 7 mit dem Pumpenteil mit kleinflächigem Verdränger in verschiedenen Positionen.

In the following embodiments of the invention will be explained with reference to a drawing. The figures of the drawing show:

Fig. 1

an oscillating positive displacement pump in a first embodiment, in which two further hydraulic pistons rigidly connected to a hydraulic drive piston transmit their force to displacers via an enclosed fluid,

Fig. 2

the positive displacement pump in one embodiment with a pressure compensation device acted upon by the liquids enclosed in two pump chambers,

Fig. 3

the positive-displacement pump in an embodiment in which, during a precompression phase, both displacers of each pump side independently bring the liquids enclosed in the pump chambers to the pre-compression end pressure,

4 to 6

in each case a section from FIG. 3 with the pump part with small-area displacer in different positions,

Fig. 7

the positive displacement pump in an embodiment in which during the Vorkompressionsphase the one liquid is brought by its associated displacer and the other liquid by a not in a delivery stroke, specially provided for precompression further displacer on Vorkompressionsenddruck, and

Fig. 8 to 10

each a section of Fig. 7 with the pump part with kleinflächigem displacer in different positions.

All displacement pumps exemplified are used for pulsation-free and in terms of flow ratio constant and uniform delivery of two liquids 10 and 11 from respectively associated reservoirs 10 'and 11' via suction lines 10 "and 11" through the positive displacement pump to a consumer, not shown here, to which Positive displacement pump downstream delivery lines 19 and 19 'lead.

The liquids 10 and 11 may e.g. be the two components of a two-component coating material for pavement markings, in which case the consumer e.g. a discharge nozzle or similar means for discharging the coating material on a roadway to be marked is.

In the following, only the process of building the same Vorkompressionsdruckes in the two pump chambers 1 and 2 of the first, in each case in the figures 1 to 3 and 7 each pump part shown on the left is to be considered; in the other, shown on the right in each case in the aforementioned figures second pump part of the same process runs in push-pull to the operation in the first pump part identically.

In the example of Figure 1, the force of a drive piston 3, here a hydraulic piston, via two pistons 6 and 7 via a fluid enclosed in two fluid chambers 8 and 9 fluid, here hydraulic oil, and two displacers 4 and 5 to two in pump chambers 1 and 2 trapped liquids 10 and 11 transferred. The fluid spaces 8 and 9 are connected to each other via a line 12 in which a check valve 13 is arranged.

Increases in a downward movement of, for example, the displacer 4 in the pump chamber 1, e.g. due to better pump space filling, the pressure faster than in the other pump chamber 2, then the pressure in the corresponding fluid chamber 8 increases and fluid is forced via the line 12 and the opened shut-off valve 13 into the fluid space 9 of the other displacer 5. Therefore, the displacer 4 remains in its downward movement, while the displacer 5 is accelerated until in both pump chambers 1 and 2 has set in about the same, dependent of the regulated by a control device, not shown hydraulic oil pressure in a drive cylinder chamber 14 of the drive piston 3 dependent pressure ,

Before the beginning of a subsequent delivery stroke, the shut-off valve 13 is closed, thus preventing fluid displacement between the fluid spaces 8 and 9 during the delivery stroke.

Between each one of the pistons 6, 7 and one of the displacers 4, 5 arranged compression springs 15 and 16 lead during the suction stroke (upstroke) the displacer 4 and 5 with open shut-off valve 13 in a central position with respect to the piston 6 and 7 back to the up and down for the following Vorkompressionsphase again ensures the full intended movement possibility. However, the compression springs cause displacement of the displacer from its initial position with respect to the pistons 6 and 7, a slight inequality of the pressures in the fluids 10 and 11, because always one of the springs is further shortened, resulting in a pressure increase in the corresponding fluid, while the other spring extended, which leads to a reduction in pressure in the other fluid. These differences are not disturbing for the function of the pump.

In the embodiment according to FIG. 2, the displacers 4 and 5 are rigidly connected to the drive piston 3 and carry out the axial movements together without relative displacements. The first pump chamber 1 is connected to a first chamber 20 and the second pump chamber 2 is connected to a second chamber 22 of a pressure compensation device 21 in each case via a line 12.1 or 12.2. The pressure compensation device 21 has a displaceable, in the two opposing chambers 20 and 22 immersed balancing piston 24. In one of the lines 12.1, 12.2, here in the line 12.1, a check valve 13 'is installed.

Increases in a downward movement of the displacer 4 and 5, the pressure due to a higher degree of filling, for example, in the first pump chamber 1 faster than in the second pump chamber 2, then shifts in now open check valve 13 'of the balance piston 24 due to the also in the chamber 20th resulting higher pressure to the chamber 22 with the lower pressure, here in the chamber 22, until in both chambers 20 and 22 and in both associated pump chambers 1 and 2 in about the same, certain of the pressure in the drive cylinder chamber 14 of the drive piston 3 Has set pressure.

Before the beginning of the subsequent delivery stroke, the shut-off valve 13 'is closed, thus preventing further displacement of the liquids in the pressure compensation device 21.

The compensating piston 21 is clamped between two axially acting compression springs 25 which, during the suction stroke with the shut-off valve 13 'open, return the balancing piston 21 to its central position, which again ensures the intended full movement possibility in both directions for the following precompression phase. With regard to the influence of the springs 25 on the liquid pressures, the same applies as stated above with reference to FIG.

In the example according to FIGS. 3 to 6, only the first displacer 4 is rigidly connected to the drive piston 3, while the second displacer 5 is relatively displaceable relative to the displacer 4. The pressure from the drive cylinder chamber 14 acts via a line 12 '' in which a shut-off valve 13 "is arranged, in a rigidly connected to the drive piston 3 cylinder 42 on a second displacer 5 associated piston 43rd

The ratio of the effective area of the piston 43 to the effective area of the second displacer 5 corresponds to the area ratio of the driving piston 3 and the displacer 4.

Under the influence of the pressure prevailing in the drive cylinder chamber 14, when the shut-off valve 13 '' is open, the same precompression pressures occur due to the relative displaceability of the drive piston 3 and the piston 43 relative to each other in both pump chambers 1 and 2 even at different degrees of filling.

Figure 4 shows a section of Figure 3 with the small-area displacer 5, in which case this displacer 5 is shown in its relative to the displacer 4 starting position in which he provided upwards and downwards full movement possibility with respect to the displacer 4 has.

If, at the beginning of the precompression phase, the second pumping chamber 2 has a lower degree of filling than the first pumping chamber 1, then the second displacer 5 moves into a forward leading relative to the first displacer 4 until the desired precompression end pressure is reached. here down shifted position, which is shown in the same section as Figure 4 facing figure 5. The size of the relative displacement depends on the size of the filling degree difference in the pump chambers 1 and 2.

On the other hand, if the degree of filling in the second pumping chamber 2 is greater than in the first pumping chamber 1, then the second displacer 5 will move into a position remaining opposite the first displacer 4, i. here shifted up position, which is shown in the same section as Figure 4 facing figure 6.

The piston 43 has on its side facing away from the displacer 5, a piston rod 44, which is led out of the cylinder chamber of the cylinder 42 and passed through a subsequent cylinder chamber 46. On the piston rod 44, an axially displaceable piston 45 is arranged. On the side facing away from the displacer 5, the piston rod 44 has a collar 47 forming an increase in diameter. Furthermore, the cylinder chamber 46 on the side facing away from the displacer 5 has a collar 48 forming a taper.

The initial position of the displacer 5 according to Figure 4, in which the displacer 5 in both directions has the intended movement, is defined by the fact that the Piston 45 on the collar 48 of the cylinder chamber 46 and the piston rod collar 47 abuts the piston 45.

If the displacer 5 moves during the precompression phase from the starting position into a position displaced downwards relative to the displacer 4, the piston 45 is driven in the same direction by the piston rod collar 47. By pressurizing the cylinder chamber 46 during the suction stroke of the two displacers 4 and 5, the piston 45 and over the collar 47 of the displacer 5 are returned back up to the starting position.

On the other hand, while the displacer 5 moves from the initial position relative to the displacer 4 into an upwardly displaced position during the precompression phase, the piston rod 44 pushes through the piston 45 resting against the cylinder collar 48, whereby the piston rod collar 47 moves away from the piston 45. During the suction stroke of the displacer 5 is due to the downward friction force at the sealing point to the pump chamber 2 and by a remaining low hydraulic pressure in the cylinder chamber of the cylinder 42 as far back until the piston rod collar 47 on the piston 45, which is pressed in the pressurized cylinder chamber 46 against the cylinder collar 48 is, comes to the plant and thus resumes its initial position.

During the delivery stroke the shut-off valve 13 'is closed, whereby a displacement of the displacer 5 relative to the displacer 4 is no longer possible, so that both displacers 4 and 5 perform the delivery stroke as rigidly connected.

In the example according to FIGS. 7 to 10, the functions "conveying" and "pre-compression pressure build-up" are shown. divided into two displacers 5 and 51. A rigidly connected to the first, large-area displacer 4 second, small-area displacer 5 takes over the fluid promotion; the further, freely displaceable displacer 51 assumes the structure of the Vorkompressionsenddruckes. The further displacer 51 and its actuating device are not, as in the embodiment of Figures 4 to 7, associated with the large-area displacer 4, but the second pump chamber 2. The rigidly interconnected displacer 4 and 5 are adjustable via the common drive piston 3. The overlying the drive piston 3 drive cylinder chamber 14 is connected via a hydraulic line 12 '''arranged therein with a shut-off valve 13''' with a cylinder chamber 53 for adjusting the other displacer 51.

FIG. 8 shows a section with the small-area displacer 5 from FIG. 7 with the further displacer 51 in its starting position, in which it has the full possibility of movement provided above and below to compensate for degree of filling in the pump chambers 1 and 2. The operating principle of the actuating device corresponds to the functional principle of the actuating device according to FIG. 4.

If, at the beginning of the precompression phase, the second pump chamber 2 has a lower degree of filling than the first pump chamber 1, then the further displacer 51, as shown in FIG. 9, moves to a position below the initial position. The size of the shift depends on the size of the filling degree difference.

If, however, the degree of filling in the second pump chamber 2 is greater than in the first pump chamber 1, then the further displacer 51 moves into a position shown in FIG Position above the initial position, as shown in FIG.

A hydraulic piston 52 fixedly connected to the further displacer 51 has, on its side facing away from the displacer 51, a piston rod 55 which is led out of the associated cylinder space 53 and passed through a subsequent cylinder space 54. On the piston rod 55, an axially displaceable piston 56 is arranged. On the side facing away from the further displacer 51, the piston rod 55 has a collar 58 forming an increase in diameter. Furthermore, the cylinder chamber 54 on the side facing away from the further displacer 51 on a collar 57 forming taper.

The initial position of the further displacer 51, as shown in FIG. 8 and in which the further displacer 51 has the full possibility of movement provided in both directions, is defined by the fact that the piston 56 rests against the collar 57 of the cylinder space 54 and the piston rod collar 58 against the piston 56 ,

Upon displacement of the further displacer 51 during the Vorkompressionsphase to a position below the initial position of the piston 56 is taken by the piston rod collar 58 in the same direction. By pressurizing the cylinder chamber 54 during the suction stroke of the displacer 4 and 5, the piston 56 and over the collar 58 of the further displacer 51 are returned back up to the starting position.

Upon displacement of the further displacer 51 in a position above the initial position, the piston rod 55 pushes through the voltage applied to the cylinder collar 57 piston 56 through, wherein the piston rod collar 58 from the piston 56 away. During the suction stroke of the displacers 4 and 5, the further displacer 51 is so far returned by a remaining small hydraulic pressure in the cylinder chamber 53 until the piston rod collar 58 on the piston 56, which is pressed in the pressurized cylinder chamber 54 against the cylinder collar 57 comes to rest and so that his starting position again.

During the delivery stroke of the displacer 4 and 5, the shut-off valve 13 '''is closed, whereby a displacement of the further displacer 51 is no longer possible.

LIST OF REFERENCE NUMBERS

character description 1 first pump chamber 2 second pump chamber 3 drive piston 4 first displacer 5 second displacer 6 first piston 7 second piston 8th first fluid space 9 second fluid space 10 first liquid to be pumped 10 ' Reservoir for 10 10 " Suction line for 10 11 second liquid to be pumped 11 ' Storage tank for 11 11 " Suction line for 11 12 Lead between 8 and 9 12 " Lead between 14 and 42 12 '' ' Lead between 14 and 53 12.1 Line between 1 and 20 12.2 Line between 2 and 22 13 - 13 '' ' Shut-off valves 14 Drive cylinder chamber 15 Spring in 4 16 Spring in 5 17.1, 17.2 suction valves 18.1, 18.2 outlet valves 19, 19 ' delivery lines 20 first chamber in 21st 21 Pressure-balancing device 22 second chamber in 21st 24 Balance piston between 20 and 22 25 Feathers in 20 and 22 42 hydraulic cylinders 43 hydraulic pistons 44 piston rod 45 sliding piston 46 cylinder space 47 Federation at 44 48 Covenant at 46 51 another displacer 52 hydraulic pistons 53 cylinder space 54 cylinder space 55 piston rod 56 sliding piston 57 Confederation in 54 58 Covenant at 55

Claims (15)

Method for operating an oscillating positive displacement pump for the simultaneous pulsation of several liquids, with for each liquid at least two pump chambers (1, 2) and movable therein displacers (4, 5), each of which a displacer (4, 5) during the actual Conveying phase of the other displacer (5, 4) sucks liquid at the end of the suction stroke reverses its direction of movement, the precompressed in the associated pump chamber (1, 2) sucked liquid in a Vorkompressionsphase and comes to a standstill upon reaching a predetermined Vorkompressionsdruckes and so long in Standstill remains until the other displacer (5, 4) has finished its liquid promotion and then begins this promotion then in turn with the promotion,
characterized,
that during the precompression pressure compensation between the individual pump chambers (1, 2) is performed and during the subsequent discharge stroke, a pressure compensation between the individual pump chambers (1, 2) is prevented. A method according to claim 1, characterized in that for each liquid to be conveyed, with a single drive piston (3) rigidly connected Pistons (6, 7) transmit their power via a fluid to each one of the piston (6, 7) associated displacer (4, 5), wherein fluid spaces (8, 9) between the individual pistons (6, 7) and the associated Displacement (4, 5) are interconnected during the Vorkompressionsphase and decoupled from each other during the delivery. A method according to claim 1, characterized in that the pressure equalization by displacement of operatively connected, the vorzukomprimierenden fluids exposed, lockable piston (24) is effected. A method according to claim 1, characterized in that the displacers (4, 5) are driven independently of each other during the Vorkompressionsphase independently come to a standstill upon reaching the desired Vorkompressionsdruckes and coupled with each other during the delivery stroke. A method according to claim 1, characterized in that the precompression by the second and each further displacer (5) associated with a pump side, each acting on the same liquid to be conveyed, hydraulically decoupled driven, lockable during the delivery stroke Vorkompressionsverdränger (51) is made. Oscillating positive displacement pump for the simultaneous pulsation of several liquids, with for each liquid at least two pump chambers (1, 2) and movable therein displacers (4, 5), each of which one displacer (4, 5) during the actual delivery phase of the other displacer (5, 4) sucks in liquid, reversing its direction of movement at the end of the suction stroke, precompresses the liquid sucked into an associated pump chamber (1, 2) in a precompression phase and stops when a predeterminable precompression pressure is reached and remains at a standstill until the other displacer (5, 4) has finished its liquid promotion and then in turn to this promotion in turn begins with the promotion
marked by
during the Vorkompressionsphase a pressure equalization between the individual pump chambers (1, 2) performing and during the subsequent delivery stroke a pressure equalization between the individual pump chambers (1, 2) preventing means. Displacement pump according to claim 6, characterized in that for each liquid to be conveyed with mutually rigidly coupled pistons (6, 7) are provided, the force of which is transferable via a fluid to one of the associated displacer (4, 5), and that between the individual pistons (6, 7) and the associated displacers (4, 5) fluid chambers (8, 9) are provided, which are connectable to each other for precompression and decoupled from each other for the delivery stroke. Positive displacement pump according to claim 6, characterized in that operatively connected, the vorzukomprimierenden liquids exposed pistons (24) are provided which are relatively releasable and displaceable for enabling the pressure equalization and which are lockable relative to each other to prevent pressure equalization. Positive displacement pump according to claim 6, characterized in that the displacers (4, 5) are independently drivable during the Vorkompressionsphase, come independently upon reaching the desired Vorkompressionsdruckes to a standstill and coupled with each other for the delivery stroke. Positive displacement pump according to claim 6, characterized in that the displacers (4, 5) for a pump side are rigidly coupled together and that the second and each further displacer (5) are assigned to a pump side Vorkompressionsverdränger (51), each to the same to be funded Act fluid and can be driven hydraulically decoupled for precompression and locked for the delivery stroke. Positive displacement pump according to claim 6, characterized in that the displacers (4, 5) for a pump side are rigidly coupled together and that between the associated pump chambers (1, 2) a pressure compensation device (21) is provided, the two with one of the pump chambers ( 1, 2) connected chambers (20, 22) and between the chambers (20, 22) lying, reciprocally displaceable balance piston (24), wherein at least one of the compounds (12.1, 12.2) between the pump chambers (1, 2 ) On the one hand and the chambers (20, 22) of the pressure compensation device (21) on the other hand by means of a valve (13 ') is selectively releasable and lockable. Positive displacement pump according to claim 7, characterized in that the fluid is a hydraulic oil and that the connection between the fluid spaces (8, 9) by a hydraulic oil line (12) is formed with a valve disposed therein (13). Positive displacement pump according to claim 7 or 12, characterized in that between the pistons (6, 7) and the respective associated displacers (4, 5) each have a spring (15, 16) is arranged, with which on the associated piston (6, 7 ) This is a force in the open valve (13) in a defined starting position can be exercised. Positive displacement pump according to claim 11, characterized in that in at least one of the chambers (20, 22) of the pressure compensation device (21) a spring (25) is arranged with the on the compensating piston (24) with an open valve (13 ') in a defined starting position-bringing force can be exercised. Positive displacement pump according to one of claims 6 to 14, characterized in that it is a conveying and metering pump of a device for producing pavement markings from a liquid, reaction-curing two-component coating material.

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