Volumetric Metering Unit

• US 20150114480A1
• Filed: 10/31/2014
• Published: 04/30/2015
• Est. Priority Date: 10/31/2013
• Status: Active Grant

• Current Assignee: Zeppelin Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Zeppelin Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: HERTEL, Stefan
• Granted Patent: US 9,594,382 B2
• Time in Patent Office: Days
• US Class Current: 137/14
• CPC Class Codes: F04B 13/00 Pumps specially modified to deliver fixed or variable measured quantities
• CPC Class Codes: F04B 13/02 of two or more fluids at the same time
• CPC Class Codes: F04B 49/03 by means of valves
• CPC Class Codes: F04B 49/035 Bypassing
• CPC Class Codes: G05D 9/00 Level control, e.g. controlling quantity of material stored in vessel
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/2673 Control by filling outlet tank or receiver

Abstract

Method and device for metering a medium from at least one storage tank by a metering device, which has a piston pump, which defines a working chamber with a cylinder and a piston, wherein in a first method step a determined filling quantity of a medium is conveyed via an inlet valve into the working chamber and the determined filling quantity is greater than the quantity to be metered and, in a second method step, the piston reduces the working chamber in size enough that only the quantity to be metered remains, wherein the excess medium flows out of the working chamber, wherein the excess medium flows via the inlet valve back into a ring line, which is connected in a medium-conducting manner to the storage tank and is arranged outside the working chamber.

Claims

1. A method for metering a medium from at least one storage tank by means of a metering device, which has a piston pump, which defines a working chamber with a cylinder and a piston, the method comprising conveying a determined filling quantity of a medium via an inlet valve into the working chamber and the determined filling quantity is greater than the quantity to be metered and, reducing, via the piston, the working chamber in size until only the quantity to be metered remains, wherein the excess medium flows out of the working chamber via the inlet valve back into a ring line, which is connected in a medium conducting manner to the storage tank and is arranged outside the working chamber.

2. The method according to claim 1, wherein the pressure inside the working chamber is measured during all of steps of the method using a pressure sensor.

4. The method according to claim 1, wherein during the discharge of the excess medium via the inlet valve from the working chamber, the pressure of the piston pump is higher than the pressure which is generated by the pump in the ring line.

3. A method for metering at least one medium by a metering device, which has a piston pump, in which a cylinder and a movable piston define a working space, the method comprising:

opening an inlet valve, wherein the piston is at the height of a cylinder base;

filling the working chamber with the medium via the inlet valve using a pump, which is arranged in the region of a ring line, until the filling quantity is greater than the quantity to be metered, and simultaneously controlling the piston in the cylinder;

monitoring the entire operation using a pressure sensor in the working chamber;

closing the inlet valve upon reaching the desired filling quantity, wherein the piston moves downward, wherein the medium is compressed inside the working chamber;

establishing the compressibility of the medium in the working chamber and adding a compensating value to the target metering quantity;

opening a bypass valve inside the ring line and opening the inlet valve;

discharging the excess medium via the inlet valve from the working chamber;

closing the inlet valve upon reaching the desired target metering quantity; and

opening an outlet valve in the region of the cylinder, wherein the target metering quantity flows via an outlet line out of the working chamber.

5. A device for metering at least one medium from at least one storage tank by a metering device and using a piston pump, which has a cylinder and a movable piston, which together define a working chamber, wherein the cylinder has at least one inlet line having an inlet valve and at least one outlet line having an outlet valve, through which at least the medium flows into or out of the working chamber,

wherein the inlet line is implemented on the cylinder as a ring line, which is arranged outside the working chamber of the cylinder and is implemented as a medium-conducting connection between the outlet and the inlet of the at least one storage tank, from which at least one tap line branches, which is connected to the inlet valve.

6. The device according to claim 5, wherein a pump, which conveys the medium inside the ring line, is arranged in the region of the ring line.

7. The device according to claim 5, further comprising a bypass having a throttle valve arranged in the region of the ring line.

8. The device according to claim 5, wherein the cylinder has a cylinder base in which at least one sensor is arranged.

9. The device according to claim 5, wherein at least one of the at least one inlet valve and the at least one outlet valve are arranged in the cylinder base.

10. The device according to claim 5, wherein the ring line has trace heating.

11. The device according to claim 5, wherein the at least one sensor is a pressure sensor.