Apparatus for measuring pressure and flow of high-temperature corrosive liquids

Abstract

An apparatus for measuring the pressure of a corrosive or high temperature process liquid includes a pressure sensor in communication with the process liquid through a vertical tube. A buffer gas injected into the vertical tube forms a liquid / gas interface at a desired height. The supply of buffer gas is then isolated or regulated so that the buffer gas pressure in the vertical tube equals the process liquid pressure. The pressure sensor indirectly measures the process liquid pressure by measuring the buffer gas pressure in the vertical tube while remaining chemically and thermally protected from the process liquid. In an embodiment, pressure measurements from a pair of gas buffer pressure sensors located upstream and downstream of the valve are combined with measurements of process liquid temperature to determine the flow rate of the process liquid through the valve.

Description

Statement of Government Interest

[0001] Portions of this invention were made with Government funding under Contract No. DE-NA0003525 and the Government may have certain rights.

[0002] This application claims the benefit of U.S. Patent Application No. 17 / 485,670, filed September 27, 2021, the disclosure of which is incorporated herein by reference in its entirety for all purposes. [Technical field]

[0003] The present invention relates to an apparatus for controlling the flow of liquids, and more particularly to an apparatus for measuring the pressure and / or flow rate of high temperature and / or corrosive liquids. [Background technology]

[0004] When controlling the flow of a process liquid, it is often desirable to measure and monitor the temperature, pressure, and / or flow rate of the liquid. Typically, the temperature of the process liquid can be measured by applying a temperature sensor to the outside of a thermally conductive barrier having an inside in contact with the process liquid. This approach is applicable to high temperature and / or corrosive process liquids.

[0005] However, most conventional sensors are not suitable for measuring the pressure and flow rate of process liquids when the process liquids are hot and / or highly corrosive.

[0006] Therefore, there is a need for an apparatus and method capable of measuring the pressure and / or flow rate of flowing high temperature and / or corrosive process liquids. Summary of the Invention

[0007] The present invention is an apparatus and method for measuring the pressure, and in embodiments also the flow rate, of a high temperature and / or corrosive process liquid. This is accomplished by connecting a pressure sensor to a process liquid conduit via a vertical tube, and establishing, and in embodiments also regulating, a column of buffer gas in the vertical tube that isolates the pressure sensor from the corrosive effects of the process liquid. Furthermore, the temperature of the column of buffer gas in the vertical tube is close to that of the process liquid, but the buffer gas has a much lower heat capacity and thermal conductivity, thus protecting the pressure sensor from damage due to the high temperature of the process liquid.

[0008] In an embodiment, the flow rate of the process liquid through the valve is determined by measuring the pressure both upstream and downstream of the valve using a gas-buffered pressure sensor connected by a vertical tube as described above. In addition, the temperature of the process liquid is measured, for example, in the valve itself. With these measurements, the flow rate can be determined according to known formulas. For example, the method taught in U.S. Pat. No. 5,251,148 can be applied, which is incorporated herein in its entirety for all purposes.

[0009] A first general aspect of the invention is a pressure measurement apparatus configured to enable measurement of a pressure of a process liquid while protecting the process liquid pressure sensor from damage by a corrosive and / or high temperature process liquid. The pressure measurement apparatus includes a process liquid pressure sensor in fluid communication with a process liquid conduit via a vertical pipe, an interface level sensing device configured to determine a level of a liquid / gas interface in the vertical pipe, a buffer gas delivery line in gas communication with the vertical pipe, and a buffer gas pressure regulator configured to regulate the pressure and / or volume of a buffer gas in the buffer gas delivery line.

[0010] In an embodiment, the interface level sensing device is an ultrasonic level sensor.

[0011] Any of the above embodiments may further include a buffer gas isolation valve configured to isolate the buffer gas pressure regulator from the downpipe.

[0012] In any of the above embodiments, the buffer gas isolation valve may be a normally closed valve.

[0013] Any of the above embodiments may further include a controller in signal communication with the process liquid pressure sensor and the interface level sensing device.

[0014] In any of the above embodiments, the controller can control the buffer gas pressure regulator. In some of these embodiments, the controller is configured to control the buffer gas pressure regulator to adjust the liquid / gas interface in the vertical pipe to a specified height.

[0015] Any of the above embodiments may further include a buffer gas pressure sensor in gas communication with the buffer gas delivery line.

[0016] Any of the above embodiments may further include a buffer gas temperature sensor in thermal communication with the buffer gas delivery line.

[0017] Any of the above embodiments may further include a buffer gas heater configured to heat the buffer gas before or while it is in the buffer gas delivery line.

[0018] A second general aspect of the present invention is a flow measurement apparatus configured to enable measurement of a flow of a corrosive and / or high temperature process liquid through a valve, the flow measurement apparatus comprising the pressure measurement apparatus according to the first general aspect, comprising a first process liquid pressure sensor in fluid communication with a process liquid conduit upstream of the valve via a first upright and a second process liquid pressure sensor in fluid communication with a process liquid conduit downstream of the valve via a second upright, first and second interface level sensing devices associated with the first and second uprights, respectively, a process liquid temperature sensor configured to sense a temperature of the process liquid, and a controller in signal communication with the first and second process liquid pressure sensors and the temperature sensor, the controller configured to determine a flow rate of the process liquid through the valve according to a temperature of the process measured by the process liquid temperature sensor and inlet and outlet pressures of the process liquid measured by the first and second process liquid pressure sensors, respectively.

[0019] In an embodiment, the process liquid temperature sensor is configured to measure the temperature of the process liquid in the valve.

[0020] In any of the above embodiments, the pressure measurement device may include a first buffer gas isolation valve configured to isolate the buffer gas pressure regulator from the first vertical pipe and a second buffer gas isolation valve configured to isolate the buffer gas pressure regulator from the second vertical pipe.

[0021] Any of the above embodiments may further include first and second buffer gas temperature sensors configured to measure first and second temperatures, respectively, of the buffer gas in the buffer gas delivery line at locations proximate the first and second vertical pipes, respectively.

[0022] Any of the above embodiments may further include first and second buffer gas pressure sensors configured to measure the pressure of the buffer gas in the buffer gas delivery line at locations proximate to the first and second process liquid pressure sensors, respectively.

[0023] A third general aspect of the invention is a method of measuring flow of a corrosive and / or high temperature process liquid through a valve, the method including providing a flow measurement device according to the second general aspect, injecting a buffer gas into first and second uprights and flowing the process liquid through the process liquid conduits and the valve, adjusting at least one buffer gas pressure regulator to adjust first and second liquid / gas interface levels in the first and second uprights, respectively, determining by a controller a flow rate of the process liquid through the valve according to pressure and temperature measurements received by the controller from first and second process liquid pressure sensors and a process liquid temperature sensor, and providing the determined process liquid flow rate to a user.

[0024] In an embodiment, the method further includes isolating the first and second vertical tubes from the buffer gas pressure regulator after adjusting the first and second liquid / gas interface levels.

[0025] In any of the above embodiments, at least one of the buffer gas pressure regulators can be maintained in gas communication with at least one of the vertical pipes during the step of determining the flow rate of the process liquid.

[0026] In any of the above embodiments, the flow measurement device may include only one buffer gas pressure regulator, and the first and second liquid / gas interface levels may be simultaneously regulated by the buffer gas pressure regulator.

[0027] And in any of the above embodiments, the flow measurement device may include only one buffer gas pressure regulator, and adjusting the first and second liquid / gas interface levels may include isolating the second vertical tube from the process liquid pressure regulator while adjusting the liquid / gas interface level in the first vertical tube, and isolating the first vertical tube from the process liquid pressure regulator while adjusting the liquid / gas interface level in the second vertical tube.

[0028] The features and advantages described herein are not exhaustive, and in particular many additional features and advantages will become apparent to those skilled in the art upon consideration of the drawings, specification, and claims.Furthermore, it should be noted that the language used in this specification has been chosen primarily for purposes of readability and instruction, and not to limit the scope of the inventive subject matter. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a block diagram of a gas buffer pressure sensor according to one embodiment of the present invention.

[0030] [Diagram 2] FIG. 2 is a flow diagram illustrating an embodiment of a method of the present invention.

[0031] [Diagram 3] FIG. 3 is a block diagram of one embodiment of the present invention configured to measure the flow rate of a process liquid through a valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The present invention is an apparatus and method for measuring the pressure, and in embodiments also the flow rate, of high temperature and / or corrosive process liquids.

[0033] 1, the apparatus of the present invention includes at least one process liquid pressure sensor 100 connected by a vertical pipe 102 to a process liquid conduit 104 configured to carry therethrough a process liquid. The apparatus further includes a buffer gas control system including a buffer gas delivery line 106 in gas communication with the vertical pipe 102, a buffer gas pressure regulator 108, and a liquid / gas transition level sensor 110, such as an ultrasonic sensor, capable of monitoring a height 122 within the vertical pipe 102 of an interface 112 between the process liquid and the buffer gas. In an embodiment, the buffer gas is nitrogen gas.

[0034] In embodiments, the buffer gas control system further includes a controller (not shown) that can monitor the buffer gas pressure sensor 114, the buffer gas temperature sensor 116, the buffer gas heater 118, and / or the height 122 of the liquid / gas interface 112 and / or the buffer gas pressure in the vertical pipe 102 as measured by the process liquid pressure sensor 100. In embodiments, the controller can further control a buffer gas pressure regulator, thereby adjusting the pressure and / or volume of the buffer gas in the buffer gas delivery line 106 to adjust and regulate the height 122 of the liquid / gas interface 112 in the vertical pipe. In some of these embodiments, the height 122 of the liquid / gas interface 112 is adjusted only during a start-up phase, after which the buffer gas regulator 108 is isolated from the vertical pipe 102. In other embodiments, the adjustment of the height 122 of the liquid / gas interface 112 continues during an operation phase following the start-up phase.

[0035] Referring to FIG. 2, in accordance with the method of the present invention, during a start-up phase 210, a buffer gas delivery line is placed in gas communication with the vertical pipe 102 and a buffer gas is introduced 200 into the vertical pipe 102.

[0036] If not already present, process liquid is then introduced 202 into the process liquid conduit 106. The pressure and / or volume of the buffer gas is adjusted 204 using the buffer gas regulator 108 until the interface 112 between the buffer gas and the process liquid in the vertical pipe 102 is established at the desired liquid / gas interface height 122 as measured by an ultrasonic sensor 110 or other liquid / gas interface measuring device. In an embodiment, the buffer gas is introduced into the vertical pipe during a start-up phase before the process liquid begins to flow through the process liquid conduit, and the pressure and / or volume of the buffer gas is initially set at or above the expected pressure of the process liquid. This ensures that the process liquid is maintained a safe distance from the pressure valve at all times, including during the start-up phase 210, once the process liquid begins to flow through the process liquid conduit.

[0037] In the embodiment of FIG. 2, once the start-up phase 210 is completed, the “normally closed” valve 120 (labeled “NC” in the drawing) in the buffer gas delivery line 106 is closed 206, thereby isolating the source of buffer gas from the vertical pipe 102, after which the pressure of the buffer gas in the vertical pipe 102 remains equal to the pressure of the process liquid even if the pressure of the process liquid fluctuates 208. In another embodiment, the buffer gas pressure regulator 108 maintains gas communication with the vertical pipe 102 even after the end of the start-up phase 210 in order to maintain the liquid / gas interface 112 at the desired height 122. As long as the interface height 122 remains constant, the buffer gas pressure in the vertical pipe 102 will be equal to the pressure of the process liquid. The pressure sensor can thereby measure and monitor the pressure of the process liquid by monitoring the pressure of the buffer gas in the vertical pipe 102, while remaining thermally and chemically protected from the process liquid by the buffer gas in the vertical pipe 102 208.

[0038] In an embodiment, the start-up stage 210 further includes heating 200 the buffer gas in the vertical pipe 102 to a temperature close to that of the process liquid to ensure that the buffer gas quickly reaches temperature equilibrium as well as pressure equilibrium with the process liquid.

[0039] 3, in embodiments of the invention, an apparatus is configured to measure the flow rate of a process liquid through a valve 300. According to these embodiments, a gas buffer pressure sensor 100 is attached to a process liquid conduit 104 both upstream and downstream of the valve 300 via a vertical tube 102. In addition, a process liquid temperature sensor 302 is provided that can monitor the temperature of the process liquid. In the embodiment of FIG. 3, the process liquid temperature sensor is installed in the valve 300 itself and is configured to measure the temperature of the process liquid as it passes through the valve 300.

[0040] A buffer gas delivery line 106 is connected to both vertical tubes 102 of the pressure sensor 100. In the embodiment of FIG. 3, a single buffer gas delivery line 106 is connected to both vertical tubes and a single buffer gas pressure regulator 108 is used to adjust the buffer gas pressure and / or volume in both vertical tubes 102, thereby establishing the liquid / gas interface 112 at a desired height 122 in the vertical tubes 102. The height 122 of the liquid / gas interface 112 in the vertical tubes 102 can be adjusted simultaneously, or a normally closed isolation valve 120 can be used to isolate the buffer gas delivery line 106 from one vertical tube 102 and then the other in sequence, allowing the height 122 of the liquid / gas interface 112 to be adjusted and optimized separately. In yet other embodiments, separate buffer gas pressure regulators (not shown) are used to control the liquid / gas interface height in each of the vertical tubes 102.

[0041] Once the start-up phase 210 is complete and process liquid is flowing through the valve 300, the measurements reported by the two gas buffer pressure sensors 100 and the process liquid temperature sensor 302 can be used to calculate the flow rate of the process liquid through the valve 300, and the calculated flow rate can be presented to a user. In an embodiment, the calculation is performed automatically by a controller or another computing device such that the flow rate is reported to a user in substantially real time.

[0042] The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. Every page of this submission, and all of its contents, however characterized, identified, or numbered, regardless of format or location within the application, is considered a substantial part of this application for all purposes. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.

[0043] Although the present application is presented in a limited number of forms, the scope of the present invention is not limited to these forms only, and various changes and modifications are possible. The disclosure presented herein does not explicitly disclose all possible combinations of features that fall within the scope of the present invention. The features disclosed herein with respect to various embodiments can generally be interchanged and combined in any combination that is not self-contradictory without departing from the scope of the present invention. In particular, the limitations presented in the following dependent claims can be combined with their corresponding independent claims in any number and in any order without departing from the scope of the present disclosure, unless the dependent claims are logically incompatible with each other.

Claims

1. 1. A pressure measurement apparatus configured to enable measurement of a pressure of a process liquid while protecting a process liquid pressure sensor from damage by a high temperature process liquid, comprising: a vertical pipe in fluid communication with the process liquid conduit and through which the process liquid is introduced; a buffer gas delivery line in gas communication with the vertical pipe for introducing a buffer gas into the vertical pipe; a process liquid pressure sensor in gas communication with the buffer gas in the vertical pipe for measuring a pressure of the process liquid via the buffer gas; an interface level sensing device configured to determine a level of a liquid / gas interface in the vertical pipe; a buffer gas delivery line in gas communication with the vertical pipe; a buffer gas pressure regulator configured to adjust the pressure and / or volume of buffer gas in the buffer gas delivery line; a buffer gas isolation valve configured to isolate the buffer gas pressure regulator from the downpipe; a buffer gas temperature sensor in thermal communication with the buffer gas delivery line; a buffer gas heater configured to heat the buffer gas before or while it is in the buffer gas delivery line; and a controller in signal communication with the interface level sensing device and the buffer gas pressure regulator and configured to control the buffer gas pressure regulator to adjust the liquid / gas interface in the vertical pipe to a specified height.

2. 2. The pressure measuring device according to claim 1, The pressure measuring apparatus, wherein the interface level sensing device is an ultrasonic level sensor.

3. The pressure measuring device according to claim 1, further comprising: A pressure measurement device comprising a buffer gas pressure sensor in gas communication with the buffer gas delivery line.

4. 1. A flow measurement device configured to enable measurement of a flow rate of a high temperature process liquid flowing through a process liquid conduit and through a valve, comprising:

1. A pressure measuring device, comprising: a first vertical pipe in fluid communication with the process liquid conduit upstream of the valve and through which the process liquid is introduced, and a second vertical pipe in fluid communication with the process liquid conduit downstream of the valve and through which the process liquid is introduced; at least one buffer gas delivery line in gas communication with the first and second vertical pipes for introducing a buffer gas to the first and second vertical pipes; a first process liquid pressure sensor in gas communication with the buffer gas in the first vertical pipe and configured to measure an inlet pressure of the process liquid via the buffer gas upstream of the valve, and a second process liquid pressure sensor in gas communication with the buffer gas in the second vertical pipe and configured to measure an outlet pressure of the process liquid via the buffer gas downstream of the valve; at least one process liquid temperature sensor configured to sense a temperature of the process liquid; a controller in signal communication with the first and second process liquid pressure sensors and the at least one process liquid temperature sensor, the controller being configured to determine a flow rate of the process liquid through the valve according to a temperature of the process liquid measured by the at least one process liquid temperature sensor and the inlet pressure and the outlet pressure of the process liquid measured by the first and second process liquid pressure sensors, respectively; Equipped with The pressure measuring device further comprises: a first interface level sensing device configured to determine a level of a liquid / gas interface in the first vertical pipe, and a second interface level sensing device configured to determine a level of a liquid / gas interface in the second vertical pipe; at least one buffer gas pressure regulator configured to adjust the pressure and / or volume of buffer gas in the at least one buffer gas delivery line; at least one buffer gas isolation valve configured to isolate the at least one buffer gas pressure regulator from the first and second downpipes; at least one buffer gas temperature sensor in thermal communication with the at least one buffer gas delivery line; at least one buffer gas heater configured to heat the buffer gas before or while the buffer gas is in the at least one buffer gas delivery line; The controller is further configured to be in signal communication with the first and second interface level sensing devices and the at least one buffer gas pressure regulator and to control the at least one buffer gas pressure regulator to adjust the liquid / gas interfaces in the first and second vertical pipes to a specified height.

5. 5. The flow measurement device according to claim 4, The flow measurement device, wherein the at least one process liquid temperature sensor includes a process liquid temperature sensor configured to measure a temperature of the process liquid within the valve.

6. 5. The flow measurement device according to claim 4, the at least one buffer gas delivery line includes a buffer gas supply line in gas communication with the first and second vertical pipes; the at least one buffer gas pressure regulator is configured to adjust a pressure and / or a volume of buffer gas in the one buffer gas delivery line; the at least one buffer gas isolation valve comprising: a first buffer gas isolation valve configured to isolate the one buffer gas pressure regulator from the first vertical pipe; and a second buffer gas isolation valve configured to isolate the one buffer gas pressure regulator from the second vertical pipe.

7. 5. The flow measurement device according to claim 4, the at least one buffer gas temperature sensor comprises first and second buffer gas temperature sensors configured to measure first and second temperatures, respectively, of the buffer gas in the at least one buffer gas delivery line at locations proximate the first and second vertical pipes, respectively.

8. The flow measurement device according to claim 4, further comprising: a flow measurement apparatus comprising first and second buffer gas pressure sensors configured to measure a pressure of the buffer gas in the at least one buffer gas delivery line at locations proximate the first and second process liquid pressure sensors, respectively;

9. 1. A method for measuring a flow rate of a high temperature process liquid through a valve, comprising: A flow rate measuring device according to claim 4 is provided, injecting a buffer gas into the first and second vertical tubes; heating the buffer gas until the temperature of the buffer gas is substantially equal to the temperature of the hot process liquid; flowing the process liquid through the process liquid conduit and through the valve; adjusting the at least one buffer gas pressure regulator to adjust first and second liquid / gas interface levels in the first and second vertical tubes, respectively; closing the at least one buffer gas isolation valve to isolate the at least one buffer gas pressure regulator from the first and second uprights; determining, by the controller, the flow rate of the process liquid through the valve according to pressure and temperature measurements received by the controller from the first and second process liquid pressure sensors and the at least one process liquid temperature sensor; providing the determined process liquid flow rate to a user. A method comprising:

10. 10. The method of claim 9, The method of claim 1, wherein the at least one buffer gas pressure regulator of the flow measurement device includes only one buffer gas pressure regulator, and the first and second liquid / gas interface levels are simultaneously regulated by the buffer gas pressure regulator.

11. 10. The method of claim 9, the at least one buffer gas pressure regulator of the flow measurement device includes only one buffer gas pressure regulator, and adjusting the first and second liquid / gas interface levels includes isolating the second vertical tube from the buffer gas pressure regulator while adjusting the liquid / gas interface level in the first vertical tube, and isolating the first vertical tube from the buffer gas pressure regulator while adjusting the liquid / gas interface level in the second vertical tube.

Images