DE2127976A1 - Dosing piston pump - Google Patents

Description

4. 6. 71

Patent attorney Hans-Jo ACHi-1 κ amtner

Graduate engineer 212 7976

6000 FRANKFURT AM MAIN

GEORr -: - VOfO'f-o, "HATE 17

Telephone: (oöii) -774604

Isnatec SA , Zurich. (Switzerland)

Do si er-K o Ib enpum pe

At Dosierpuiapen, as they are for example in the chemical process and analysis technology and for medical-biological Purposes are used, there are high demands on the continuity of the liquid delivery and placed on the reproducibility of the delivery rate. The respective delivery rate should also be within a wide range be changeable, and with the simultaneous operation of several pump channels, the constancy of a certain one Ratio of the set delivery rates must be guaranteed over the longest possible period.

Peristaltic pumps have been developed which are suitable for the purposes mentioned above and largely meet the requirements. In addition to their relatively simple functional structure, they have the main advantage that the liquid to be conveyed does not come into contact with the mechanical parts causing the conveyance. In contrast, there is disadvantage ₅

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that the hoses are often replaced because of their wear and tear Need to become. Furthermore, there is the phenomenon that the delivery rate in continuous operation due to poor stability the hose elasticity gradually decreases, so that in certain cases an ongoing monitoring of the Delivery rate is required, whereby the respectively emerging decrease in the delivery rate by corresponding Acceleration of the drive must be compensated.

The piston pump is far superior to the peristaltic pump in terms of mechanical stability.

The invention therefore aims to create a metering piston pump with continuous, pulsation-free liquid delivery, which while avoiding the disadvantages the peristaltic pumps have the same operational possibilities with regard to the variability of the delivery rate.

The metering piston pump according to the invention is thereby characterized that the pump has at least two, one each Cylinders with pistons having pump heads with alternating "conveying pistons, whose conveying strokes are partially overlap, and that the pump heads together form a unit which can be separated from the drive and which is opposed to a corresponding Pump unit is exchangeable with a different stroke volume of the pump heads. .

In the drawing, exemplary embodiments of the invention are shown, namely show:

1 shows a metering piston pump according to a first Embodiment of the invention, in section, with the control valve arranged in the drive block;

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Fig. 2 shows a metering piston pump according to a second embodiment of the invention, in section, in which the Control valves are arranged in the pump unit;

3 shows a modified control valve block of a metering piston pump, similar to that of FIG Cut, and

Fig. 4- a dosing piston pump according to another Embodiment of the invention, in section, with a rotary slide valve arrangement .

The dosing piston pump shown in Fig. 1 consists of a drive block 1 and one arranged on this, exchangeable pump unit 2. The two identical pump heads 3 and 4 are on a base plate 5 mounted and each contain a piston 6 and a cylinder 7, which form the displacement 8. The cylinder 7 sits in the Bore of a housing 9 »which also receives the sealing means for sealing the piston 6. In the present In the case of piston seals, so-called V-rings 10, which are under the influence of a compression spring 11, are used. The piston 6 is inserted in a piston holder 12 which, at its collar 13, is in a bore 14 - of the base plate 5 is led.

To drive the piston 6 for the delivery stroke, a plunger 15, which is loosely attached to the piston holder 12, is used is longitudinally guided in a sleeve 16 in the drive block 1 and at the lower end carries a roller 17 on which a cam disk 18 acts. The cam disk 18 is seated on a drive shaft 19, which is provided by one for both pump heads common drive machine (not shown)

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is driven. The piston 6 is returned by a spring 20 ₄ which acts on the collar 13 of the piston holder 12. "

On the displacement 8 of each pump head 3 or 4 is a connecting line which alternately serves as a suction and pressure line 21 connected, which via a arranged between the base plate 5 and an upper end frame 22 of the drive block 1, releasable coupling to a in the drive block 1 housed control valve 23 leads. The detachable coupling consists of two pluggable Kupp-P lungsliälfteh 24 · and 25, with the upper coupling half 24 inserted into a hole on the underside of the base plate 5 and with the connection nipple screwed in from above 26 is in operative connection, while the lower coupling half 25 is resilient with the aid of a spring 27 is arranged in the end frame 22 of the drive block 1 and connected to a connection nipple 28. The pressure, with which the two coupling halves 24, 25 are pressed together, can be done by turning the connection nipple 26 change within certain limits.

The base plate 5 of the pump unit 2 is fastened with screws 29 attached to the end frame 22 of the drive block 1. After loosening these screws 29, the pump unit 2 be lifted off the drive block 1, whereby the drive connection to the pump heads and the couplings 24, 25 assigned to the connecting lines 21 to solve. The remote pump unit 2 can be replaced by a corresponding Pump unit with a different stroke volume of the pump heads can be replaced. With the assembly of the pump unit

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on the drive block 1 is the drive connection and the connections of the suction and pressure lines are made automatically so that the pump can be restarted immediately is ready for use.

Because the piston stroke is given by the drive assembly is, the interchangeable pump units with different stroke volumes only differ with regard to the piston area.

The IC cam 18 are so formed and with respect to their rotational position so that the two pump heads 5 and 4 work as follows:

To simplify the explanation, the pistons of the two pump heads labeled A and B. During the delivery stroke of piston A, piston B sucks in and vice versa. Piston B ends the intake stroke and begins the delivery stroke before the delivery stroke of piston A ends is, in this transition phase, in which both pistons promote, the movement of the piston A is delayed to the same extent that the piston B accelerates, so that the delivery rate remains constant and that no shocks occur in the liquid delivery. At the end of the delivery stroke of the piston A, the concomitant piston B has reached its full speed, and the piston A is with a speed which is greater than that during the delivery stroke, returned, with the liquid sucks. At the end of the intake stroke, the piston A stops briefly, until the beginning of the next transition phase, in which the piston A intervenes again in the delivery process and the delivery of the piston B reduces

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is changed. Finally, the piston B is returned in the manner indicated, after which the working cycle is repeated.

The control valve 23 of each pump head is operated in a manner not shown in detail, e.g. by a switching mechanism, which is controlled by a cam disk seated on the drive shaft 19.

In all applications in which the Liquid, for example, must not come into contact with metal, be it that the metal has been attacked by the liquid would, be it that metal ions could get into the liquid in an undesired way, preferably all ' Liquid-carrying parts of the pump made of glass and / or a suitable plastic. The piston 6 can e.g. made of glass, especially borosilicate glass, and the cylinder 7 e.g. made of polytetrafluoroethylene (trade name: Teflon) exist, or vice versa.

With the dosing piston pump described, achieve a continuous, pulsation-free liquid delivery. Due to the forced stroke and return of the Pistons and the compulsory control of the valves, the liquid is in reproducible quantities and independent of pressure promoted so that the same thing in ^ every work phase Volume and the same flow rate prevail.

Particularly noteworthy is the problem-free interchangeability of the pump units and thus the change from one delivery volume to another. Several pump units can be arranged next to one another and thus combined to form a unit with a common drive machine, whereby the delivery rate !! of the individual pump units can be different *, so that at the same time several _t under = *

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Different liquids are conveyed with different volumes per unit of time, which also change by changing the drive speed, e.g. with the help of a gearbox coupled to the drive machine Allow limits to be changed proportionally. This makes the pump particularly suitable for the precise dosing of various. Liquids in certain proportions.

The metering piston pump described has the further advantage that by exchanging the pump units and changing the drive speed can change the delivery rate in a much larger range than with the peristaltic pump and that pressures up to about 50 atü can be achieved, which means that the upper pressure limit of peristaltic pumps is exceeded ten times.

In the dosing piston pump according to Fig. 1, as described, to the displacement of each pump head a connecting line alternately serving as a suction and pressure line connected via a between the pump unit and the drive block arranged, detachable coupling to a forced control valve housed in the actuation block leads.

As a result of the separate arrangement of the control valve from the pump heads, which connects said connecting line makes it necessary, when the pump unit is exchanged, the liquids to be pumped will be contaminated.

With the dosing piston pumps described below this sometimes disadvantageous circumstance is avoided by that the Purap heads with forcibly controlled control valves to form a drive that can be separated from a common drive

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Unit are assembled * The interchangeable Puiapen unit thus includes all parts that come into contact with the liquid to be conveyed and works without dead volume, so that contamination of the liquids to be conveyed is avoided when the pump unit is replaced.

The dosing piston pump shown in Fig. 2 consists of a drive block JO and one arranged on this exchangeable pump unit 31 »

In the lower housing block 32 of the pump unit 31, two pump heads are combined, each having a piston 33 or 34 in a cylinder bore .35 or 36. The means for sealing the piston are shown in the drawing for the sake of simplicity omitted.

each piston 33 or 34- sits at the upper end of an in not shown in more detail, longitudinally guided push rod 37 or 38, which at its lower end has a roller 39 or carries on which a cam 41 or 42 acts, which is used to drive the piston 33 or 34 for the delivery stroke. The cam disks 41, 42 sit on one in the housing 43 of the drive block 30 mounted drive shaft 44, which is coupled to a drive machine, not shown. The return of the pistons 33, 34 takes place in each case by a Spring 45 or 46.

In a arranged on the housing block 32, with this firmly connected upper housing block 47 of the pump unit 31 are the forcibly controlled control valves housed. The pump heads 33, 35 and 34, 36 are individually assigned longitudinally movable valve slides 48 and 49, which between in the housing block 47 and on the housing «

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block 32 loosely mounted sealing bodies 50 »51 and 52 slide. The package of these sealing bodies 50, 51 and 52 and the valve spools 48 and 49 located in between is under a lateral pressure from the springs 53 and 54, which are used to adjust the pressure Support set screws 55 and 56, is exercised. Two further springs 57 and 58, which are inserted into blind bores 59 and 60 of the housing block 47 are arranged, press the Sealing bodies 50 and 52 also against the upper end face of the housing block 32.

• The outer sealing bodies 50 and 52 each contain a channel 61 or 62, which leads from the displacement of the relevant pump head 33, 35 or 34, 36 to that of this pump head Valve slide 48 or 49 leads and alternately with one of the obliquely extending slide openings 63 and 64 or 65 and 66 is in connection. In the middle seal body 51 are two parallel channels 67 and 68, of which the upper duct 67 in the picture with the outlet line 69 (pressure line) visible in cross section of the Pump is connected and alternately with the slide openings 63 and 65 of the two valve slides 48 and 49 in Is connected and of which the lower channel 68 in the picture with the inlet line 70 visible in cross section (suction ~ line) of the pump and alternately with the slide openings 64 and 66 of the two valve slides 48 and 49 is in communication. In the position shown, the valve slide 48 and 49 is the displacement of the pump head 33, 35 Via the channel 61, the slide opening 63 and the Channel 67 connected to the output line 69, and the

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2127978

The displacement of the pump head 34 _s 36 is connected to the input line 70 via the channel 52, the slide opening 66 and the channel 68 «

The valve spools 4-8 and 49 are driven in same way as that of pistons 33 and 34- with the help of cams 71 and 72 »which are also on the drive shaft 44 seated. Each valve slide 48 or 49 is provided with a push rod 73 or 74, which at its lower End of a roller 75 "or 76 carries on which the cam disc 71 or 72 acts. Using one leather 77 resp.

78, the rollers 75 "76 are held with the cam 7I ₁ 72 in contact.

So that the movable ^ the pistons 33, 34 and the Valve slide 48, 49 containing parts of the puropen unit 31 do not fall out when the drive block 30 is separated from the drive block 30, which is necessary to replace the same, are appropriate Holding means provided, which (but are not shown in the drawing.

The cam disks 41, 42, 71 and 72 are designed in this way and arranged with respect to their rotational position in such a way that, in turn, those associated with Pig. I described the operation of the two pump heads 33, 35 and 34, 36 with the associated control valves results.

FIG. 3 shows a comparison with FIG. 2 slightly modified control valve block of a metering Kolb'enpumpe which may be the same configuration is otherwise as that of Fig 2 ₀ Mutually corresponding parts are provided with the same Besugszeichen as in Flg.. 2.

. Unlike the Au3führungsform to 2 comparable -

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run in the example according to FIG. 3, the slide openings 63, 64 and 65, 66 in the valve slides 48 and 49 are not inclined, but perpendicular to the plane of movement of the valve slides. The production of the slide openings is thereby facilitated * The channels 61 and 62 in the outer sealing bodies 50 and 52 branch off towards the respective one Valve slide 48 or 49 in two channels 79 »80 or 81, 82, the branch channels 79 and 81 with the channel 67 and the branch channels 80 and 82 with the channel 68 in the middle Sealing body 51 run coaxially.

Furthermore, FIG. 3 shows another solution in relation on the generation of the pressure forces required to seal the displacements and the control valves. Instead of Springs 53, 54 (Fig. 2), adjusting screws 83, 84, 85 and 86 are provided with which the sealing bodies 50, 51 and 52 and the valve slides 48 and 49 lying between these are laterally pressed against one another. Are accordingly the springs 57, 58 (FIG. 2) are also replaced by adjusting screws 87 and 88. The sealing body can thus be of three Sides can be readjusted using the adjusting screws 83 to 88.

4 shows a further embodiment of the metering piston pump according to the invention, with a rotary slide valve arrangement.

The pump in turn consists of a drive block 89 and an exchangeable one arranged on it Pump unit 90. The pump unit 90 comprises a base plate 91, an intermediate plate 92 and one of the pump heads and housings containing the rotary slide valve assembly

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block 93 »which are firmly connected to one another in a manner not shown. Two pump heads are combined in the housing block 93, each having a piston 94 or 95 in a cylinder bore 96 or 97. The means for piston sealing are omitted in the drawing for the sake of simplicity "-" -.- ■

The pistons 94 · »-95 are driven in the same way As in the previously described exemplary embodiments, with the aid of cams 98 »99» on one in the housing 100 of the drive block 89 seated drive shaft 101 and each act on a roller 102 or 103, "- the at the lower end of the piston push rod 104 or 105 attached is. The return spring is 106 or 10? designated.

The forcibly controlled control valves for the two pump heads have a common, rotatable one Valve slide 108 on the vertical axis in the housing block 93 between the two pump heads with ball bearings 109 »110 is stored. Of those visible in cross section Input and output lines 111 and 112 in the rotary valve ^ 108 lead channels 113 and 114- radially outward where they with the inlet (suction) channels 115 and 116 or with the Outlet (pressure) channels 117 and 118 of the two pump heads alternatively contact. For this purpose, the rotary valve 108 is rotated back and forth. The corresponding Drive movement is provided by a bevel gear, which consists of two bevel gears seated on the drive shaft 101 119 and 120 and a third bevel gear 121 consists, which latter sits at the lower end of a shaft 122, the is connected to the rotary valve 108. The sprockets of the

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both bevel gears 119 and 120 are interrupted by gaps, so that the remaining groups of teeth of one KggeIzahm? ades the gaps in the other bevel gear face. In this way, the third bevel gear 121 is always only with one of the driving bevel gears 119,120 engaged, and the rotary valve 108 is. alternately with continuous rotation of the drive shaft 101 moved in one and the other direction of rotation.

The intake ducts 114, 115 and 116 and the exhaust ducts 113, 117 and 118 are mutually and externally sealed with the aid of sealing rings 123.

The mode of operation of the dosing piston pump according to FIG. 4 is otherwise the same as in the previously described embodiments.

The rotary slide valve arrangement described last has the advantage that with a single valve slide the pumping action of two or more pump heads at the same time can be controlled.

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Claims (6)

"", PATSiTANWALTY % ö. 71 Hans -Joachim Kantner 'DiPtOM - Engineer 8000 FRANKFURT AM MAIN 2 T27g76 ^^ 1J dosing Eolben pump with continuous, pulsation « free liquid delivery, characterized in that the pump at least two, each one cylinder (7) with piston (6) having pump heads (3,4 ·) iftit alternately conveying Has pistons whose delivery strokes partially overlap, and that the pump heads (3.4 ") together have one of the drive (1) . Form a separable unit (2) against a corresponding Pump unit with a different stroke volume of the pump heads can be exchanged. '(Fig. 1) · ^ 2. Dosing piston pump according to claim 1, characterized in that that the pump unit (2) has a base plate (5) on which the pump heads (3 »4) are mounted and the with 3inem drive block (1) is detachably connected, that further that each piston (6) with one in a bore (14) of the Base plate (5) guided piston holder (12) is connected, which under the influence of a longitudinally guided in the drive block (X), the plunger (15) resting loosely on the piston holder (12) and a return spring (20), and that the plunger (15) is actuated by a cam (18). (Fig. I) 3. Dosing piston pump according to claim 2, characterized in that a connecting line (21) serving alternately as a suction or pressure line is connected to the displacement (8) of each pump head (3, 4) and is connected via an intermediate base plate (5) and drive block (1) is arranged, releasable coupling (24,25) housed in a drive block (1), forcibly gesteuerton control valve (23) ^leads · (Fig. 1) 109852/1265 4. Dosing piston pump according to claim 1, characterized in that that the pump heads (33,35l34-, 36) with forcibly controlled control valves (48,4-9) to one of a common Drive (30) separable unit (31) are assembled. (Pig. 2) - 5. Dosing piston pump according to claim 4, characterized in that that the control valves are arranged in a housing block (4?) built on the pump heads (33,35 »34,36) and longitudinally movable valve slides (48, 49) which are individually assigned to the pump heads and which are between two outer sealing bodies closing off the displacement of the pump heads (50,52) and a sealing body (51) lying between them slide, and that the overflow channels (61,62,67,68) containing sealing body (50,51,52) im Housing block (47) are loosely stored and by external Pressure forces, on the one hand, against the sealing surfaces of the valve slides (48, 49) and, on the other hand, the outer sealing bodies (50, 52) also against the sealing surfaces of the pump heads (33.35; 34.36) are pressed. (Fig. 2) 6. Dosing piston pump according to claim 5, characterized in that that the sealing bodies (50,51,52) are pressed against the sealing surfaces with adjusting screws (83 to 88). (Fig. 3) 7 · Dosing piston pump according to claim 4, characterized in that that they have a rotary slide valve arrangement with a rotary slide valve common to the pump heads (33,35; 34,36) (108). (Fig. 4) Patent attorney Hans-Joachim Kantner ~ Graduate engineer ^ inftßco / iVrr graduate engineer . _/ «^». » 109652 / T 26b eooo Frankfurt am Main Z _x / / · Geohg-Voiot-Strasse \ v * r * - * ^c TELBPHUN: (0β11) -7Γ «Μ