HK1192935B - Liquid mass measurement and fluid transmitting apparatus - Google Patents

Abstract

A liquid mass measurement and fluid transmitting apparatus includes a container for measurement of a mass of fluid therein. A sensor is coupled to the container which measures a mass of fluid within the container independent of variations of pressure within the container. A diaphragm sensor may be located on the bottom of the container whereby electrical signals representing the mass of fluid within the cylinder are created by movement of the diaphragm caused by the mass of fluid thereon. A pressure equalizer which equalizes the pressure within the container to the pressure on the opposite side of the diaphragm allows the measurement of the mass to occur independent of any variations and pressure within the container. Liquid within the mass of liquid within the container can be accurately measured such that a desired mass of liquid may be transmitted for further use. The liquid may be vaporized and transmitted as a vapor.

Description

Liquid mass measurement and fluid delivery device

Cross Reference to Related Applications

The present application claims benefit of U.S. application No.13/088,796 entitled "LIQUID MASSMEASUREMENT AND flip transmission APPARATUS", filed on day 18, month 4, 2011. The entire contents of this application are incorporated by reference into this disclosure.

Technical Field

The present invention relates to the field of fluid flow measurement and control, and in particular to a system for delivery of a measured quantity of liquid mass or a vaporized quantity of liquid mass.

Background

Various industrial processes require the introduction of precise quantities of liquid or vaporized liquid. For many processes, the delivery rate of the liquid or vapor must be accurately measured and controlled to achieve acceptable results. Such processes include, for example, blood diagnostics, titration, dosing, chamber humidification, evaporation, stripping, annealing, and chemical corrosion.

Conventional liquid and vapor mass delivery systems rely on technologies such as displacement metering pumps, time-based pressure distribution, heat-based flow controllers, ultrasonic, differential pressure, and Coriolis (Coriolis). Although each of these techniques has certain drawbacks, they have in common the lack of immunity to entrained air. To reduce the error caused by entrained gas, many manufacturers of liquid flow controllers recommend the installation of a degassing device. This equipment adds cost and complexity to the delivery system and also introduces other potential errors, namely that the efficiency of the degassing process is compromised.

Conventional vapor delivery systems include bubblers, evaporators, and flash evaporators. For each such vapor delivery system, multiple devices are required to deliver a precursor of the vapor (precursor) to the process chamber. A drawback of bubblers is that the ratio of chemical vapor to carrier gas changes as the liquid temperature or bubbler pressure changes. Although bubbler vapor output feedback compensation techniques have been developed to compensate for these effects, this adds significant cost to the system. A drawback of the vaporizer is that a mass flow control device is still required to control and report the flow rate of the vaporized precursor. And the delivery of reactive chemical vapors may affect the accuracy of the flow control device or cause it to fail prematurely. A drawback of flash evaporators is that they require liquid flow control equipment, such as a volumetric displacement pump or liquid mass flow controller, to inject precise quantities of liquid into a heated chamber maintained at a temperature sufficient to vaporize the liquid. The liquid injection technique introduces potentially significant errors, and the temperature of the vaporizer must typically be maintained at or above the decomposition temperature of the chemical.

Object of the Invention

It is therefore an object of the present invention to provide a liquid mass measurement and fluid delivery device that provides a direct indication of the quality of residence (residual) despite fluctuations in liquid temperature, applied pressure and concentration of gases dissolved in the liquid.

It is another object of the invention to provide a device to control the introduction or extraction of a precise mass of liquid to support the process. It is still another object of the present invention to provide an apparatus for facilitating the handling of various liquid chemicals that can be added together to achieve precise mixing. It is yet another object of the present invention to provide a system that facilitates reporting and controlling delivery of vapor-phase (vapor-phase) liquids to support processing. And yet another object of the present invention is to provide a device that accumulates the mass of precursor passing through the apparatus over a specified period of time.

Disclosure of Invention

The present invention provides an apparatus for measuring and reporting the total mass of a liquid contained within a container despite fluctuations in liquid temperature, applied pressure, and dissolved gas concentration in the liquid.

In one aspect of the invention, the parameters to be measured are the mass of resident liquid contained in the container and the controlled delivery of a precise amount of mass introduced into or extracted from the container. In another aspect of the invention, the parameters to be measured are the mass of the resident liquid contained in the vessel and the mass of the vapor phase extracted therefrom.

In its simplest form, the apparatus comprises a sensor for communicating with a container, such as a sealed cylinder (sealed column) having one or more conduits connected thereto, means for controlling the movement of fluid through the conduits, and a method of bi-directional communication with the sensor and a fluid communication control system. Furthermore, the sensor is able to detect the mass of liquid in the cylinder, independent of the sealing pressure.

In one aspect of the invention, a fluid quality measurement and delivery system is provided that includes a sensor coupled to a container. The sensor is configured to generate one or more electrical signals proportional to the mass of fluid in the container independent of changes in pressure on the liquid. The system also includes an inlet in fluid flow communication with the container and a fluid outlet in fluid flow communication with the container to allow fluid to be delivered from the container. A controller is electrically coupled to the sensor to receive and process the electrical signals. The controller provides a measure of the mass of liquid in the container and may also control the amount of fluid added to or removed from the container. The controller may also control other devices in the system to control and/or monitor various parameters, such as pressure and temperature.

The system may also include a flow control inlet valve coupled to the fluid outlet and a flow control outlet valve coupled to the fluid inlet. The controller is electrically coupled to the flow control inlet valve and the flow control outlet valve. A pressure sensor may be coupled with the container to sense a pressure therein. One or more pressurization conduits may be coupled to the vessel to control the pressure applied (alert) in the vessel. The boost conduit may be coupled to or may include one or more control valves electrically coupled to the controller. The controller may be configured to control a flow rate of fluid delivered from the controller through the fluid outlet. The system may include a temperature sensor coupled to the vessel and the controller and a heater coupled to the vessel. A controller is configured to control a temperature and/or pressure in the vessel to change the fluid from a liquid to a vapor.

The sensor may be a diaphragm sensor adapted to sense a change in the mass of fluid in the container, wherein the fluid in the container is located above the diaphragm. A pressure equalizer may be operatively connected to the sensor to equalize the pressure applied to both sides of the diaphragm. The pressure equalizer may include a conduit having a first end in fluid communication with the container above the liquid in the container and a second end in fluid communication with an area proximate a side of the diaphragm facing away from the liquid in the container.

According to the invention, the change in the output signal of the sensor as liquid is introduced into or removed from the container is directly related to the change in the mass of resident liquid, independent of any change in the gas pressure of the sealed container. The movement of a precise amount of liquid mass can be transported to and from the system at pressures ranging from sub-atmospheric to 68bar (bar) (1000 psi). In one possible application, high vapor pressure fluids may be monitored and transported as liquids, which provides significant accuracy advantages over vapor phase measurement techniques. In another possible application, the vacuum can be kept at a low vacuum (< 1)0^-4Atmospheric pressure) to process and manage the pressure sensitive liquid.

In another aspect of the invention and in its simplest form, the apparatus includes a sensor for communicating with a container having one or more conduits connected thereto, means for controlling the movement of fluid through the conduits and a method for bi-directional communication with the sensor and fluid transport control means. Also, devices for converting a liquid to a vapor are included. Additional useful features of the invention include, but are not limited to, introducing a sweep gas (sweep gas) through the top of the liquid in the vessel, drawing a carrier gas up through the liquid, and/or thermally inducing a phase change.

Drawings

The invention may be carried out in different ways and several embodiments will be described by way of example with reference to the accompanying drawings, which are schematic illustrations of devices.

Fig. 1 is a block diagram showing the arrangement of an apparatus to support the measurement and dispensing of an accurate mass of ejected liquid according to the present invention;

FIG. 2 is a block diagram illustrating another embodiment of an apparatus to support measurement of liquid and controlled delivery of mass flow rates in accordance with the present invention;

FIG. 3 is a block diagram illustrating another embodiment of a measured mass and flow rate controlled delivery of a liquid to support vaporization in accordance with the present invention.

Detailed Description

FIG. 1 is a block diagram in accordance with an aspect of the present invention. Referring to fig. 1, an apparatus according to one aspect of the invention comprises a container in the form of a sealed cylinder 2. Located at the bottom of the vessel is a mass sensor 1. The mass sensor 1 is a diaphragm-type mass sensor that includes a diaphragm that senses a force thereon and transmits an electrical signal representative of a value of the force. An example of such a sensor is Model216 (Model 216) or 316 sensor commercially available from GP:50, Greenland Island (Grand Island), N.Y.. The sensor 1 is mounted at the bottom of the sealing cylinder 2 in such a way that the liquid 13 therein exerts a force on the membrane of the sensor 1. This force is used to represent the mass of the liquid 13 in the cylinder 2. The sensor 1 transmits an electrical signal to the controller 16 via the electrical connection 15. The controller processes the electrical signal 15 into a measure of the mass of the liquid 13 in the column 2. The membrane in the sensor 1 comprises a first side which supports and faces the liquid 13 in the cylinder 2. The opposite side or face of the diaphragm in the sensor 1 faces away from the liquid and is proximate to the cavity 26. A pressure equalizer is coupled between the cylinder 2 and the chamber to equalize the pressure in the chamber 26 and the cylinder 2 above the liquid 13 therein. Accordingly, the sensor 1 will measure the mass of the liquid 13 independent of changes in pressure in the column 2 and changes caused by changes in entrained gas and temperature in the column 2.

The inlet 3 is in fluid flow communication with the cylinder 2 and comprises an inlet flow control device 8, such as a valve. The inlet flow control device 8 is coupled to the controller 16 via an electrical connection 21 to allow the controller to control the amount of fluid (whether in liquid or vapor form) flowing into the column 2. The outlet 4 is also in fluid flow communication with the cylinder 2 and comprises an outlet flow control device 9, for example a valve. The output flow control device 9 is coupled via an electrical connection 17 with a controller 16 to allow the controller to control the amount of fluid (whether in liquid or vapour form) flowing out of the column 2.

One or more pressure control conduits 5, 6 are in fluid communication with the cylinder 2 to control the pressure 12 in the vessel 2. One or more pressure control conduits may comprise one or more pressure control valves 10, 11 to control the flow of fluid in said conduits 5, 6. As shown in fig. 1, the pressure supply conduit 6 comprises an isolation valve 11. The isolation valve 11 is connected to a controller 16 via an electrical connection 18 to control the opening and closing of the isolation valve 11 to allow pressurised fluid to flow into the cylinder 2 via the conduit 6. A pressure relief conduit 5 may also be used to allow pressurized fluid (e.g., gas) in the cylinder 2 to escape therefrom. The isolation valve 10 is also connected to the controller 16 via an electrical connection 20. The controller 16 is also electrically connected to the pressure sensor 14 via an electrical connection 19 to read an electrical signal from the pressure sensor 14 that is representative of the pressure 12 in the cylinder 2. Based on the pressure in the cylinder 2, the controller can control the amount of pressurized fluid in the vessel via conduit 6 by controlling the isolation valve 11. And, the controller 16 can control the pressure in the cylinder 2 by the controller sending a signal to the control isolation valve 10 to allow the pressurized fluid (e.g., gas) in the cylinder 2 to be exhausted from the isolation valve 11 via the conduit 5.

The sensor 1 is in direct communication with the bottom of the closed cylinder 2 and in indirect communication with the top of the closed cylinder 2 through a pressure equalizer, such as a conduit 7. When there is no liquid in the closed cylinder 2, the sensor signal 15 is at its minimum. If the pressure 12 in the cylinder 2 changes, this pressure change is also transmitted via the conduit 7 to the back of the diaphragm in the sensor 1, while the output signal 15 remains unchanged. When liquid is introduced into the cylinder 2 through the conduit 3, the output signal of the sensor 1 increases, which is directly related to the speed of mass increase. Conversely, if liquid is removed from the cylinder 2, the output signal of the sensor 1 decreases, which is directly related to the speed of mass reduction. The controller 16 may be capable of measuring and monitoring the rate of mass increase in the cylinder.

In one embodiment, the internal volume of the closed cylinder 2 is 2 cubic centimeters and has a value of 1 at 20 degrees Celsius¹/₂Cubic centimeter H₂O, which is a general limitation to prevent overfilling of the containment cylinder 2. Also in this embodiment, the output signal 15 of the sensor 1 is 0-10 volts. In the dry state the sensor signal 15 is 0 regardless of the pressure condition 12 of the cylinder 2, since a force is exerted on both sides of the sensor 1. As liquid is introduced into the closed cylinder 2, a force is exerted on the membrane of the sensor 1, resulting in an increase of the sensor signal 15. Also, in this embodiment, the controller 16 receives the output signal 15 of the sensor 1 and converts it into grams. If pure water is being introduced, the sensor outputs a signal at a mass of 1.497 grams of fluidNumber 15 will reach 10 volts. If the substance is mercury, the output signal of the sensor 1 will also be 10 volts at 1.497 grams of fluid, but the denser fluid will only occupy 0.11 cubic centimeters of the closed cylinder 2. The output signal of the sensor 1 is directly related to the resident mass residing in the closed cylinder 2, independent of the fluid density, the temperature in the cylinder and/or the pressure at the top of the cylinder. The resolution of the sensor 1 output signal may be 0.00015 grams/millivolt so that very small mass amounts of motion may be accurately detected.

In another embodiment, the internal volume of the closed cylinder 2 is 1000 cubic centimeters and it has an available liquid effective volume of 750 cubic centimeters of water at 20 degrees celsius. In this embodiment, 500g of pure water introduced into the closed cylinder 2 causes the output signal of the sensor 1 to be 6.6786 volts. This indicates that the mass to signal ratio is close to 0.075 grams/millivolt.

In another embodiment and in the continuation of the first embodiment, the cylinder 2 has a value corresponding to 1 at 20 degrees celsius¹/₂Useful effective volume of cubic centimeter of water (1.497 grams of water). The conduit 3 is connected to a supply of water which is sufficiently pressurised. When the conduit isolation valve 8 receives a drive signal 21 from the control system 16, water is introduced into the containment cylinder 2. When the output signal 15 of the sensor 1 reaches 9 volts (a user-defined fill-up value), the control system 16 terminates the drive signal 21. At this time, the mass of water in the cylinder 2 was 1.3473 g. The user defines a desired liquid dispense (dispense) mass to be 0.50 grams through interaction with the controller. The controller 16 calculates the delta sensor signal voltage (3.34 volts =0.50 grams) associated with the defined dispense quality. A dispense command is issued and the controller 16 stores the initial sensor 1 output signal value and transmits a drive signal 17 to the conduit isolation valve 9. As the liquid exits the closed cylinder 2 through the conduit 4, the signal 15 of the sensor 1 drops. Controller 16 monitors the output signal of sensor 1 and terminates the dispense event when the actual signal equals the initial signal minus the delta volts calculation. If the user has defined that cylinder 2 is refilled after each dispense (refill)) The controller 16 transmits the actual signal via the connection 21. The refilling event of the closed cylinder 2 is terminated when the output signal of the sensor 1 reaches 9 volts.

The liquid dispense pressure 12 is monitored by a pressure sensor 14 and communicated to a controller 16. If the pressure 12 of the containment cylinder 2 is less than the user's specification, the controller 16 transmits an actual signal 18 to the isolation valve of the conduit 6. The inlet of the conduit 6 is commonly referred to as a suitable pressurized gas supply. When the pressure 12 of the closed cylinder 2 equals a user defined value, the isolation valve 11 of the conduit 6 is closed. If the pressure 12 exceeds a user-defined value, the isolation valve 10 is opened and the pressure 12 of the containment cylinder 2 is reduced.

Fig. 2 depicts a block diagram of another embodiment of the present invention. The system of fig. 2 is the same as that described in fig. 1, except for the addition of a proportional control valve 21 disposed in conduit 4. The flow rate control valve 21 is used to control the mass transfer rate of the liquid outputted from the closed cylinder 2. The user defines in practice the desired liquid mass flow and the duration of the transfer. The desired speed in one embodiment is 0.1 grams per minute and the duration of the transmission is 10 minutes. When the controller 16 receives a start command, the isolation valve 9 of the conduit 4 is opened. The signal of the sensor 1 transmitted via the connection 15 is monitored by the controller 16 and the valve signal 22 of the flow rate control valve 21 is increased until the rate of decrease of the output signal of the sensor 1 matches the target rate corresponding to a mass loss of 0.1 grams per minute.

Fig. 3 depicts a block diagram of another embodiment of the present invention. The system of fig. 3 is similar to that shown in fig. 2, wherein like numerals indicate like parts. However, the system in fig. 3 allows for the transport of fluid in the vapor phase. To achieve this, the liquid 13 is vaporized by reducing the pressure 12 on the liquid 13 and/or by heating the liquid 13 to increase its vapour pressure. Thus, the system includes a heater 23 operatively connected to the controller 16 via an electrical connector 24. Likewise, the temperature sensor 24 is operatively connected to the controller 16 by an electrical connection 25. The controller 16 reads a signal from the temperature sensor 24 and adjusts the amount of heat transferred from the heater 23 to the cylinder 2 to bring the temperature in the cylinder 2 to a desired level, which is typically defined by the user. The controller 16 controls the pressure 12 and the temperature in the column 2 in such a way that the conditions in the column are at the desired level. By controlling these conditions, the liquid 13 in the container can be vaporized and transported via the conduit 4 after the liquid quality measurement.

In one embodiment, water vapor is required to support a sub-atmospheric pressure (< 1 torr) annealing process. The outlet conduit 6 is routed to a process chamber (not shown) and, in response to a user input command, the controller 16 increases the input signal to the proportional control valve 21, which is transmitted along connection 22, when the isolation valve 11 is open, until the output signal 15 of the sensor 1 decreases at a rate corresponding to a user-defined vapor mass transfer rate. In another embodiment, silicon tetrachloride vapor is required to support the chemical vapor deposition process. In this embodiment, the controller 16 increases the pressure in the closed cylinder 2 to and controls at a user-defined value. Thermal energy is added to the liquid by internal or external heating means 23. The controller 16 increases or decreases the increase in thermal energy as needed to maintain the pressure 12 in the vessel at a desired value.

While embodiments of the present invention have been illustrated and described in detail by the present disclosure, the present disclosure is to be considered as illustrative and not restrictive in character. Any modifications and variations that fall within the spirit of the invention are considered to be within the scope of the invention.

Claims (18)

1. A liquid mass measurement and fluid delivery device, the device comprising:

a container configured to contain a liquid for measuring a mass thereof;

a mass sensor operably associated with the container to generate one or more electrical signals proportional to a mass of liquid in the container independent of pressure changes of the liquid, the mass sensor comprising:

a diaphragm adapted to sense a change in the quality of liquid in the container, wherein the diaphragm is positioned such that liquid in the container is above the diaphragm;

an inlet in fluid flow communication with the vessel;

an outlet in fluid flow communication with the vessel to allow fluid to be delivered from the vessel;

a controller electrically coupled to the mass sensor to receive and process the electrical signal; and

a pressure equalizer comprising a conduit configured to equalize a pressure on the liquid and a pressure on a side of the diaphragm facing away from the liquid, wherein the conduit has a first end in fluid communication with the container above the liquid in the container and a second end in fluid communication with a region proximate to the side of the diaphragm facing away from the liquid in the container.

2. The apparatus of claim 1, further comprising at least one of a flow control inlet valve coupled to the inlet and a flow control outlet valve coupled to the outlet.

3. The apparatus of claim 2, wherein the controller is electrically coupled to the flow control inlet valve and the flow control outlet valve.

4. The apparatus of claim 3, further comprising a pressure sensor coupled to the container for measuring a pressure therein.

5. The apparatus of claim 4, further comprising one or more pressurization conduits coupled to the reservoir to control the pressure exerted in the reservoir.

6. The apparatus of claim 5, wherein the one or more pressurization conduits are coupled with one or more control valves that are electrically coupled with the controller.

7. The apparatus of claim 6, wherein the controller is configured to control a flow rate of fluid delivered from the container through the outlet.

8. The apparatus of claim 7, further comprising a temperature sensor coupled to the vessel and the controller.

9. The apparatus of claim 8, further comprising a heater coupled to the container.

10. The apparatus of claim 8, wherein the controller is configured to control a temperature and a pressure within the vessel.

11. A method for measuring liquid mass and conveying fluid, the method comprising:

containing a liquid in a container having an inlet and an outlet in fluid flow communication with the container such that the fluid is delivered from the container, wherein,

a mass sensor coupled to the container, in operative association with the container, to generate one or more electrical signals proportional to a mass of liquid in the container independent of pressure changes of the liquid, the mass sensor comprising: a diaphragm adapted to sense a change in a mass of liquid in the container, wherein the liquid in the container is located above the diaphragm;

a controller electrically coupled to the mass sensor to receive and process the electrical signal; and

a pressure equalizer comprising a conduit configured to equalize a pressure on the liquid in the container and a pressure on a side of the diaphragm facing away from the liquid, wherein the conduit has a first end positioned above the liquid in the container and in fluid communication with the container and a second end in fluid communication with a region proximate to the side of the diaphragm facing away from the liquid in the container;

generating one or more electrical signals indicative of the mass of the liquid in the container proportional to the mass without relying on pressure changes on the liquid using a sensor operably associated with the container; and

receiving and processing the electrical signal using a controller electrically coupled to the mass sensor.

12. The method of claim 11, further comprising an inlet flow control valve coupled to an inlet of the vessel and an outlet flow control valve coupled to an outlet of the vessel.

13. The method of claim 12, further comprising controlling a flow rate of fluid delivered from the container through the outlet using the controller.

14. The method of claim 13, wherein the inlet flow control valve and the outlet flow control valve are electrically coupled to the controller.

15. The method of claim 14, further comprising controlling the pressure exerted in the vessel using one or more pressurization conduits coupled with the vessel and a pressure sensor coupled with the vessel.

16. The method of claim 15, further comprising sensing a temperature within the vessel using a temperature sensor coupled with the vessel and the controller.

17. The method of claim 16, further comprising heating the fluid within the container using a heater coupled to the container.

18. The method of claim 17, further comprising controlling a temperature and pressure within the vessel using the controller to allow the fluid to change from a liquid to a vapor.