WO2015078487A1

WO2015078487A1 - Metering and delivery pump for chemically aggressive and/or abrasive fluids

Info

Publication number: WO2015078487A1
Application number: PCT/EP2013/074746
Authority: WO
Inventors: Gerhard Walter
Original assignee: Oest Holding Gmbh
Priority date: 2013-11-26
Filing date: 2013-11-26
Publication date: 2015-06-04

Abstract

The invention relates to a metering and delivery pump (1) for chemically aggressive and/or abrasive fluids (4), - having a housing (20), in which a delivery chamber (3) is arranged, into which the fluid (4) to be delivered can be introduced via a suction line (5) which has an upstroke valve (6), and from which delivery chamber (3) the fluid (4) can be discharged via a pressure line (8) which has a delivery valve (7), - having a metallic separating element (2) which can be adjusted in the delivery chamber (3) and separates the fluid (4) to be delivered from a pneumatic or hydraulic medium (24), - having a drive device (21) which loads the pneumatic or hydraulic medium (24) by means of hydraulic or pneumatic negative pressure or positive pressure and, as a result, moves the separating element (2) and generates the negative/positive pressure which is required for the delivery movement of the fluid (4) in the delivery chamber (3). It is possible as a result to deliver even very highly aggressive fluids (4) without danger.

Description

Dosing and delivery pump

The invention relates to a metering and delivery pump for chemically aggressive and abrasive fluids. The invention also relates to a metering and delivery pump device with at least two such metering and delivery pumps.

When pumping liquids with abrasive fillers and / or chemically aggressive components usually pumps without dynamic seals are used. Such pumps can be divided into two groups of the type: The pumps of the first group bypass the dynamic seal by the necessary drive movement is transmitted through a hermetically sealed housing by means of magnetic force. The second group of such pumps preferably utilizes an elastic membrane which together with the pump housing forms a hermetic separation from the environment. The elastic membrane must forcibly join a pulsating motion during the conveying process. For the most part elastomers are used for such membrane. In order to achieve an acceptable service life even at a high delivery pressure, in the second group of pumps a pneumatic or hydraulic support of the diaphragm is used to reduce the pressure difference partially or completely. A disadvantage of such pumps with membranes made of elastomers, however, is that elastomers can in principle diffuse substances with a very small molecular structure and thus be damaged.

The present invention therefore deals with the problem of providing an improved embodiment for a metering and delivery pump, which can also be used in particular for chemically aggressive and abrasive liquids and gases, ie in general fluids. This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the general idea of forming a separating element (membrane) previously formed of an elastomer now of metal, which has a dense molecular structure such that it is diffusion-tight with respect to almost all substances. The metering and delivery pump according to the invention in this case has a housing in which a delivery chamber is arranged, in which the fluid to be delivered via a suction valve having a suction line can be introduced and from which the fluid via a pressure valve having a pressure line can be discharged. Arranged in the delivery chamber is the adjustable and metallic separating element according to the invention, which separates the fluid to be delivered from a pneumatic or hydraulic (drive) medium. Also provided is a drive device which acts on the medium by means of hydraulic or pneumatic negative pressure or overpressure and thereby moves the separating element and generates the required for the conveying movement of the fluid under / over pressure in the delivery chamber. By using a metallic separating element, as already mentioned above, an almost diffusion-proof separating element can be created, which also permits the conveying of chemically aggressive or abrasive fluids, that is to say liquids and gases. In addition, the life of such a metallic separator can be significantly increased if the differential pressure is kept as small as possible. In the metering and delivery pump according to the invention, this is achieved in that the movement of the separating element is realized exclusively hydraulically or pneumatically. This means that only the hydrostatic pressure in the interior causes the necessary lifting movement for the promotion. In a further advantageous embodiment of the solution according to the invention, the separating element is designed as a metallic bellows, with a bellows support whose guide rod is guided through the housing to the outside, wherein the guide rod is formed as hydraulically or pneumatically acted upon by the drive means piston. Such a metallic bellows allows a comparatively large stroke movement and thus also a comparatively large delivery volume, wherein, moreover, extremely precise guidance of the bellows is possible due to the guide rod guided through the housing wall of the housing. The bellows is tightly welded to the housing on one side and sealed to the bellows support on the opposite side.

Appropriately, at least one displacement sensor is provided, which monitors a position of the guide rod and thus indirectly also a position of the bellows carrier or the bellows. Additionally or alternatively, a position sensor may be provided which detects a deflection of the bellows. By means of a monitoring device which is communicatively connected to the position sensor and the displacement sensor, thus the movement of the bellows can be accurately monitored. By monitoring in particular an overuse of the metallic bellows can be prevented as a result of impermissible movement / overstretching and thereby its life can be significantly extended. The constant monitoring of the movement of the metallic bellows is on the one hand for a long life on the other hand for the prevention of unpredictable failure incidents of great importance.

In a further advantageous embodiment of the solution according to the invention, the housing is formed of metal. In order to also reliably prevent unwanted diffusion of chemically aggressive constituents through the housing. To be able to prevent sig this is just like the metal diaphragm formed of metal, so that even highly aggressive media can be safely transported with such a metering and delivery pump.

In a further advantageous embodiment of the solution according to the invention, an evaluation unit is provided, which is communicatively connected to the position sensor and the displacement sensor and is designed such that it calculates a delivery volume of the fluid from a movement of the bellows. Additional, exposed to the aggressive fluid volume meter are thus unnecessary, so that by means of the evaluation extremely high flow rate can be calculated.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, in each case schematically, 1 shows a longitudinal section through and a view of a metering and delivery pump according to the invention,

2 shows a metering and delivery pump device with two metering and

Feed pumps,

3 is a detailed view of Fig. 1,

4 shows a continuously operating metering and delivery pump device with two metering and delivery pumps with a pneumatic linear motor arranged between them, FIG.

5 shows a continuously operating metering and delivery pump device with two metering and delivery pumps with crank mechanism,

Fig. 6 is a continuously operating metering and delivery pump device with two metering and feed pumps and a hydraulic pump.

According to FIG. 1, a metering and delivery pump 19 according to the invention for chemically aggressive and / or abrasive fluids 4 has a housing 20 with a first housing part 10 and a second housing 18 connected fluid-tight thereto. In the housing 20, a delivery chamber 3 is arranged, in which the fluid to be delivered 4 via a suction valve 6 having a suction line 5 can be introduced and from which the fluid 4 via a pressure valve 7 having a pressure line 8 can be discharged. The suction valve 6 or pressure valve 7 arranged in the first housing part 10 can of course also be arranged in the second housing part 18. According to the invention, a metallic separating element 2, which separates the fluid 4 to be conveyed from a pneumatic or hydraulic medium 24, is arranged so as to be translationally adjustable in the conveying space 3. Also provided hen is a drive device 21 which acts on the pneumatic or hydraulic medium 24 by means of hydraulic or pneumatic negative pressure or pressure and thereby moves the separating element 2 and generates the required for the conveying movement of the fluid 4 under / over pressure in the delivery chamber 3. This means that only the hydrostatic pressure in the interior 15 causes the lifting movement necessary for the promotion.

Looking at Fig. 1, it can be seen that the separating element 2 is formed as a metallic bellows, with a bellows support 9, the guide rod 1 1 is guided by a housing wall, that is in the present case by the first housing part 10 to the outside , The guide rod 1 1 itself serves only to guide the metal bellows 2 and the passage of the medium 24 from the cylinder 16 in a bellows interior 15 and back. The guide rod 1 1 is hollow and channel-like and thus has a cavity 12. In order to be able to detect an adjustment movement of the metallic bellows and thus of the separating element 2, at least one displacement sensor 13 is provided which detects a position of the guide rod 11 and indirectly also a position of the bellows carrier 9 or of the separating element 2. The displacement sensor 13 is preferably arranged on the drive side in the medium 24, since an arrangement in the delivery chamber 3 and thus the fluid 4 directly exposed disadvantages. Additionally or alternatively, a position sensor 17 may be provided, which detects a deflection of the bellows. Via a monitoring device 22, a movement of the bellows and thus generally of the separating element 2 can be monitored, wherein the monitoring device 22 can be communicatively connected to the position sensor 17 and the displacement sensor 13. The constant monitoring of the movement of the separating element 2 and the metallic bellows is on the one hand for a secure long life on the other for the prevention of unforeseen incidents of crucial importance. Also may be provided an evaluation 23, which is communicatively connected to the position sensor 17 and / or the displacement sensor 13 and, moreover, designed such that a displacement of the bellows, that is generally the separating element 2, a delivery volume of the fluid 4 is calculated. In general, it should be noted that it is not necessary to provide both a displacement sensor 13 and a position sensor 17. The distance measurement allows a measurement of the displaced medium and can be used for volume flow calculation. The position sensor 17, however, usually has a pure monitoring function, which can be taken over theoretically by the displacement sensor 13.

Referring again to Fig. 1, it can be seen that in the interior of the guide rod 1 1, a cavity 12 is arranged, in which the hydraulic or pneumatic medium 24 can flow unhindered. The hydraulic or pneumatic medium 24 can be moved by the drive device 21 by means of a piston 14 oscillating between the bellows interior 15 and the cylinder 16, in which the piston 14 is mounted translationally adjustable, back and forth. By means of a reciprocating movement of the piston 14, the bellows is thus moved via the hydraulic or pneumatic medium 24 and thus the fluid 4 to be delivered is conveyed.

Moves the piston 14 as shown in FIG. 1 to the left, the hydraulic or pneumatic medium 24 flows into the bellows interior 15 and moves the bellows in the direction of the second housing part 18. This reduces the volume in the sealed delivery chamber 3 and the fluid 4, which was previously sucked in via the suction valve 6, is now pressed via the pressure valve 7 into the pressure line 8. After reaching the delivery end position, the piston 14 is reversed by the drive means 21, whereby the pneumatic or hydraulic medium 24 flows back into the cylinder 16 and thereby retracts the bellows support 9. The metallic bellows is thereby compressed. miert and thereby increases the volume in the delivery chamber 3 and a negative pressure is generated. The fluid 4 now flows under the action of the air pressure or by means of a pre-pressure pump in the delivery chamber 3 a.

By means of the metallic bellows used according to the invention or in general the metallic separating element 2 and the housing 20 formed of metal, even highly aggressive fluids 4, that is to say gases or liquids, can be conveyed safely, without having to fear that chemically aggressive components, for example through the separating element 2, here through the bellows, diffuse through. By means of the displacement sensors 13 and the position sensors 17, moreover, the service life of the separating element 2, that is to say here specifically of the metallic bellows, can be prolonged, since overstressing due to impermissible movement can be reliably prevented.

If one looks at the Fig. 2, one can see in this a metering and delivery pump device 25 according to the invention with two shown in FIG. 1 metering and delivery pumps 19. The two metering and delivery pumps 19 are mechanically separated from each other, but interactively coupled together, so that preferably the left metering and feed pump 19 sucks when the right metering and feed pump 19 just pushes and vice versa. By such a coupling, the suction and pressure stroke of the two metering and feed pumps 19 can be coordinated so that no pressure drops occur in the pressure line 8.

FIG. 3 shows a detailed illustration from FIG. 1, in which the monitoring device 22 and the evaluation unit 23 are likewise arranged on the drive side in the medium 24. In this way, in particular space can be saved. In Fig. 4, a metering and feed pump device 25 is shown with two continuously operating metering and feed pumps 19, are arranged in the two metering and feed pumps 19 similar to a boxer engine opposite and moved by an intermediate pneumatic linear motor 26. If pressure is applied to the right-hand chamber 27, the pistons 14 move to the left, whereby the right-hand metering and delivery pump 19 draws in fluid 4 and the left-hand metering and delivery pump 19 discharges fluid 4. If, on the other hand, the left chamber 28 is pressurized, the pistons 14 move to the right, as a result of which the left metering and delivery pump 19 sucks and the right metering and delivery pump 19 ejects fluid 4.

In the same way, the metering and delivery pump device 25 according to FIG. 5 also functions, in which case a crank drive 29 serves as a drive device 21.

In the metering and delivery pump device 25 according to FIG. 6, a hydraulic pump 30 with corresponding valve device 31 is provided as the drive device 21, which acts directly on the medium 24 and allows very precise control of the metering and delivery pump device 25, since the friction in consequence the leadership and seal the piston 14 deleted.

All embodiments of FIGS. 4-6 have in common that the metering and delivery pump device 25 shown enable a continuous fluid requirement.

*****

Claims

claims

1 . Dosing and Forderpumpe (19) for chemically aggressive and / or abrasive fluids (4),

- With a housing (20) in which a delivery chamber (3) is arranged, in which the fluid to be delivered (4) via a suction valve (6) having suction line (5) can be introduced and from which the fluid (4) via a a pressure valve (7) having pressure line (8) can be discharged,

- With a in the delivery chamber (3) adjustable metallic separating element (2) which separates the fluid to be delivered (4) from a pneumatic or hydraulic medium (24),

- With a drive device (21) which acts on the pneumatic or hydraulic medium (24) by means of hydraulic or pneumatic negative pressure or pressure and thereby moves the separating element (2) and the for the conveying movement of the fluid (4) required under / over pressure in the delivery chamber (3) generated.

2. dosing and feed pump according to claim 1,

characterized in that

the separating element (2) is designed as a metallic bellows with a bellows carrier (9) whose guide rod (1 1) is guided through the housing (20) to the outside.

3. dosing and feed pump according to claim 2,

characterized in that the guide rod (1 1) is hollow and channel-like, that is an inner cavity (12).

4. dosing and feed pump according to claim 2 or 3,

characterized in that

at least one displacement sensor (13) is provided which detects a position of the guide rod (1 1).

5. dosing and feed pump according to one of claims 2 to 4,

characterized in that

at least one position sensor (17) is provided, which detects a deflection of the bellows.

6. dosing and feed pump according to claim 5,

characterized in that

a monitoring device (22) is provided, which is communicatively connected to the position sensor (17) and / or the displacement sensor (13) and monitors a movement of the bellows.

7. dosing and feed pump according to one of claims 1 to 6,

characterized in that

the housing (20) is formed of metal.

8. metering and delivery pump according to one of claims 5 to 7,

characterized in that

an evaluation unit (23) is provided, which communicates with the position sensor (17) and / or the displacement sensor (13) and is designed such that it calculates a delivery volume of the fluid (4) from a movement of the bellows.

9. metering and delivery pump device (25) with at least two metering and delivery pumps (19) according to one of claims 1 to 8, which are connected to each other such that the one metering and delivery pump (19) fluid (4) emits while the other dosing and feed pump (19) sucks fluid (4), whereby a continuous flow is created.