Method and apparatus for providing constant liquid rates and dispensing precisely repeatable liquid volumes

• US 7,757,891 B2
• Filed: 03/14/2007
• Issued: 07/20/2010
• Est. Priority Date: 03/14/2007
• Status: Expired due to Fees

• Current Assignee: Chemflow Systems, Inc.
• Original Assignee: Chemflow Systems, Inc.
• Inventors: Moulton, Russell D., Han, Leon
• Primary Examiner(s): Nicolas; Frederick C.
• Application Number:
  US11/685,765
• Publication Number:
  US 20080223483A1
• Time in Patent Office: 1,224 Days
• Field of Search: 222 64- 69, 222/71, 222/108, 222/110, 2224245-425, 222/426, 222/428, 222442-444, 222/450, 222/481.5, 141/198, 137/139, 137/391, 137/144, 738/61, 731/49
• US Class Current: 222/64
• CPC Class Codes: G01F 11/284 combined with electric level detecting means G01F11/282, G01F11/30 - G01F11/46 take precedence
• CPC Class Codes: G05D 7/0676 by action on flow sources G05D7/0688, G05D7/0694 take precedence

Abstract

Techniques for dispensing a type of liquid in a specific amount or at a constant flow rate are disclosed. According to one aspect of the present invention, a height difference between an inlet and an outlet is maintained by an adjustable tubing assembly. An overflow assembly is provided to divert any overflow of the liquid from entering a reservoir and keep a specific level of the liquid. A valve is provided to the inlet and can be turned off when a sensor detects that there is an overflow of the liquid in the overflow assembly.

Claims

1. A dispensing system comprising:

a reservoir, uprightly positioned and connected to a tubing assembly, with an opening coupled to an inlet via a valve and an overflow assembly;

an outlet connected to the reservoir via a tubing assembly,

wherein the overflow assembly is physically positioned apart from the outlet by a height difference, the outlet is movable upwards or downwards by repositioning the tubing assembly, a type of fluid flows into the reservoir via the inlet and the valve and exits in a specific amount from the outlet, the specific amount precisely determined by the height difference between the inlet and the outlet.

2. The dispensing system as recited in claim 1, wherein when a liquid reaches beyond a level of the overflow assembly, the liquid goes to the overflow assembly.

3. The dispensing system as recited in claim 2, wherein the overflow assembly includes a vent and an overflow opening.

4. The dispensing system as recited in claim 3, further comprising a reservoir that is provided to collect an overflow of the liquid from the overflow opening.

5. The dispensing system as recited in claim 2, wherein the overflow assembly includes a sensor that causes the valve to turn off when the sensor detects that there is an overflow of the liquid in the overflow assembly, the sensor causes the valve to turn on after the specific amount of fluid is dispensed.

6. The dispensing system as recited in claim 1, wherein the inlet is physically positioned higher than the outlet.

7. The dispensing system as recited in claim 1, wherein the tubing assembly includes a release valve that, when opened, allows a liquid to slowly bleed gravity from the tubing assembly.

8. The dispensing system as recited in claim 7, further comprising a first sensor and a second sensor on the reservoir, the first sensor provided to detect a level of the liquid in the reservoir, the second sensor provided to detect any overshoot of the liquid beyond a level of the first sensor.

9. The dispensing system as recited in claim 8, wherein, when the liquid drops to a level equal to or just slightly below a level of the first sensor, the first sensor causes the release valve to close.

10. The dispensing system as recited in claim 8, wherein, if a flow rate of the liquid through the valve is high, the liquid in the reservoir overshoots beyond a level of the first sensor, which is detected by the second sensor that in return causes the valve to close.

11. The dispensing system as recited in claim 1, wherein the opening of the reservoir is to prevent air bubbles from being accumulated or introduced into the dispensing system.

12. The dispensing system as recited in claim 1, further comprising an outlet valve connected between the outlet and the tubing assembly.

13. The dispensing system as recited in claim 12, wherein the outlet valve is only opened to release air trapped in the dispensing system when the liquid is entering the reservoir.

14. The dispensing system as recited in claim 12, wherein the outlet valve is closed while the liquid is filling the reservoir up to a level of the overflow assembly.

15. The dispensing system as recited in claim 14, wherein the specific amount of the liquid is dispensed from the dispensing system.

16. The dispensing system as recited in claim 1, wherein a constant height of a liquid is maintained by keeping the liquid level in the reservoir at a level, the constant height of the liquid maintains a constant head pressure on the liquid exiting through the outlet, resulting in a constant flow rate.