Mass flowmeter and mass flow controller having the same

Abstract

To provide a mass flowmeter capable of reducing the probability that a sensor is damaged by high-pressure fluid.SOLUTION: A mass flow meter 1 includes a conduit body 10 and a sensor 12. The conduit body has a main flow passage 14, a first sensor branch passage 16, a second sensor branch passage 18, and a housing chamber 20, both ends of the first and second sensor branch passages being connected respectively to the main flow passage and the housing chamber. The sensor has an inlet gas nozzle 36 and an outlet gas nozzle 38, and is disposed in the housing chamber. The inlet gas nozzle is connected to the first sensor branch passage and the outlet gas nozzle is connected to the second sensor branch passage so that a part of the fluid flowing through the main flow passage enters the sensor via the first sensor branch passage and returns to the main flow passage via the second sensor branch passage to enable measurement of a fluid flow rate. The conduit body is further provided with a pressure chamber 40 and an airway 42.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a technology for detecting and controlling the flow rate of fluids such as liquids and gases, and more particularly to a mass flow meter and a mass flow controller having a mass flow meter that can reduce the probability that a sensor will be destroyed by pressure. [Background technology]

[0002] A mass flow controller (MFC) is a device for measuring and controlling the flow rate of a fluid, taking temperature and pressure into consideration. In recent years, it has been widely used to measure and control the flow rate of compressible fluids such as gases and liquids. The main components of a mass flow controller generally include a mass flow meter (MFM), a control valve, and a controller. A mass flow meter has a pipeline and a sensor. The pipeline functions as a filter, stabilizes the flow, and connects the sensor to the control valve. The sensor monitors the flow rate of the fluid passing through the pipeline and sends a flow rate signal to the controller. The controller adjusts the flow rate of the fluid flowing through the pipeline by controlling the control valve according to the flow rate signal.

[0003] The most important component of the mass flow controller is obviously the mass flow meter. Currently, the two types of mass flow meters commonly found on the market are thermal mass flow meters and Coriolis mass flow meters. Thermal mass flow meters measure flow using the thermal diffusion effect of gas, while Coriolis mass flow meters measure flow based on the Coriolis principle.

[0004] In practice, it has been found that because the pipes and sensors are made of different materials (usually the pipes are metal and the sensors are plastic), the sensors are often destroyed or leak due to the high pressure fluid in the pipe body, preventing the sensor from accurately detecting the fluid flow rate. Summary of the Invention

[0005] An object of the present invention is to provide a mass flow meter and a mass flow controller for the mass flow meter that can reduce the probability that a sensor will be destroyed by a high-pressure fluid.

[0006] In order to achieve the above objects and effects, the present invention provides a mass flow meter including a pipe body and a sensor. The main pipe body has a main flow path, a first sensor branch flow path, a second sensor branch flow path, and a storage chamber. Both ends of the first sensor branch flow path and the second sensor branch flow path are connected to the main flow path and the storage chamber, respectively, and a filter is provided in the main flow path. The sensor has an inlet gas nozzle and an outlet gas nozzle and is disposed in the chamber. The inlet gas nozzle is connected to a first sensor branch channel and the outlet gas nozzle is connected to a second sensor branch channel, and a part of the fluid that has passed through the main channel enters the sensor via the first sensor branch channel and then returns to the main channel via the second sensor branch channel, thereby measuring the flow rate of the fluid. The conduit body is further provided with a pressure chamber and an airway. The pressure chamber is connected to the storage chamber, and the airway is connected to both the storage chamber and the main flow path, and a portion of the fluid that has passed through the main flow path enters the pressure chamber via the airway, thereby equalizing the pressure inside and outside the sensor.

[0007] The present invention provides a mass flow controller that includes a conduit body, a sensor, and a control valve. The conduit body has a main flow path, a first sensor branch flow path, a second sensor branch flow path, a storage chamber, a post-valve main flow path, a first valve branch flow path, and a second valve branch flow path. Both ends of the first sensor branch flow path and the second sensor branch flow path are connected to the main flow path and the storage chamber, respectively. One end of the first valve branch flow path is connected to the main flow path, and one end of the second valve branch flow path is connected to the post-valve main flow path. A filter is provided in the main flow path. The sensor is disposed in the chamber and has an inlet gas nozzle and an outlet gas nozzle, the inlet gas nozzle being connected to a first sensor tributary channel and the outlet gas nozzle being connected to a second sensor tributary channel, and detects the flow rate of the fluid by causing a portion of the fluid passing through the main channel to enter the sensor via the first sensor tributary channel and then return to the main channel via the second sensor tributary channel. The control valve has a valve inlet and a valve outlet and is mounted on the pipeline body. The valve inlet is connected to a first valve branch passage and the valve outlet is connected to a second valve branch passage, so that fluid in the main passage enters the control valve through the first valve branch passage and then enters the main passage after the valve through the second valve branch passage. The control valve adjusts the flow rate of the fluid flowing out of the valve outlet according to the flow rate detected by the sensor. The conduit body is further provided with a pressure chamber and an airway. The pressure chamber is connected to the storage chamber, and the airway is connected to both the pressure chamber and the main flow path, and a portion of the fluid that has passed through the main flow path enters the pressure chamber via the airway, thereby equalizing the pressure inside and outside the sensor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a first preferred embodiment of the present invention, showing the appearance of a mass flow meter; [Figure 2] 1 is an exploded cross-sectional view of a first preferred embodiment of the present invention; [Figure 3] 1 is a combined cross-sectional view of a first preferred embodiment of the present invention; [Figure 4] FIG. 4 is a partially enlarged view of FIG. [Figure 5] FIG. 1 is a cross-sectional view of a second preferred embodiment of the present invention showing a mass flow controller having a mass flow meter. DETAILED DESCRIPTION OF THE INVENTION

[0009] As shown in FIGS. 1 to 4, the mass flow meter 1 disclosed in the first preferred embodiment of the present invention includes a pipe body 10 and a sensor 12.

[0010] The conduit body 10 is made of metal and is provided with a main flow path 14, a first sensor tributary flow path 16, a second sensor tributary flow path 18, and a storage chamber 20. The main flow path 14 has a flow path inlet 22 at one end of the conduit body 10 and a flow path outlet 24 at the other end. Both ends of the first sensor tributary flow path 16 and the second sensor tributary flow path 18 are connected to the main flow path 14 and the storage chamber 20, respectively, and the first sensor tributary flow path 16 is closer to the flow path inlet 22 than the second sensor tributary flow path 18. A first joint 26 is connected to the flow path inlet 22 to introduce fluid into the main flow path 14. A second joint 28 is connected to the flow path outlet 24 to discharge the fluid in the main flow path 14. A filter 30 is disposed within the main flow path 14 to filter the fluid. An airtight ring 32 is provided on top of the filter 30 and abuts against the wall of the main flow path 14, positioned between the first sensor tributary flow path 16 and the second sensor tributary flow path 18, allowing some fluid to enter the first sensor tributary flow path 16 from outside the filter 30.

[0011] One side of the chamber 20 is open at the outer surface of the conduit body 10. After the sensor 12 is placed in the chamber 20, the chamber 20 is closed by a closure 34 fixed to the conduit body 10. The sensor 12 has an inlet gas nozzle 36 connected to the first sensor tributary channel 16 and an outlet gas nozzle 38 connected to the second sensor tributary channel 18.

[0012] With the above combination, most of the fluid that enters the main flow path 14 from the first joint 26 passes through the filter 30, while a portion of the fluid passes from outside the filter 30 through the first sensor tributary flow path 16 to enter the sensor 12, and then returns to the main flow path 14 through the second sensor tributary flow path 18. In this way, the sensor 12 can detect the flow rate, pressure, temperature, humidity, etc. of the fluid and emit detection signals accordingly.

[0013] The main feature of the present invention is that a pressure chamber 40 and an airway 42 are provided in the conduit body 10. The pressure chamber 40 is connected to the storage chamber 20, and both ends of the airway 42 are connected to the pressure chamber 40 and the main flow path 14, respectively, so that a portion of the fluid passing through the main flow path 14 enters the pressure chamber 40 via the airway 42. This makes the pressures inside and outside the sensor 12 approximately the same, reducing the possibility that the sensor 12 will be damaged by the high-pressure fluid that has entered the sensor 12.

[0014] 4, in the first preferred embodiment, the volume of the chamber 20 is larger than that of the sensor 12. Therefore, after the sensor 12 is placed in the chamber 20, a space is formed between the sensor 12 and the sidewall of the chamber 20, and this space becomes a pressure chamber 40. In other words, the pressure chamber 40 is a part of the chamber 20, and a part of the space is not occupied by the sensor 12. The diameter of each of the first sensor tributary channels 16 is larger than that of the inlet gas nozzle 36 of the sensor 12, and this space becomes an airway 42 between the inlet gas nozzle 36 and the sidewall of the first sensor tributary channel 16. Most of the fluid passing through the first sensor tributary channel 16 enters the sensor 12 through the inlet gas nozzle 36, and a part enters the pressure chamber 40 through the airway 42, thereby maintaining the same pressure inside and outside the sensor 12. In practice, the above effect can be achieved by installing an O-ring 44 only on the outlet gas nozzle 38 to provide an airtight seal between the pressure chamber 40 and the second sensor tributary channel 18, without installing an O-ring on the inlet gas nozzle 36.

[0015] As shown in FIG. 5, a second preferred embodiment of the present invention provides a mass flow controller 2 including the mass flow meter 1 disclosed in the first preferred embodiment and a control valve 46.

[0016] As described above, the mass flow meter 1 includes a conduit main body 10 and a sensor 12. The conduit main body 10 has a main flow path 14, a storage chamber 20, a first sensor tributary flow path 16, a second sensor tributary flow path 18, a pressure chamber 40, and an airway 42. The above-described component structures are the same as those described above, and therefore will not be described further. Differences include the following: The conduit main body 10 further includes a post-valve main flow path 48, a first valve tributary flow path 50, and a second valve tributary flow path 52. A partition wall 54 is provided between the main flow path 14 and the post-valve main flow path 48 to prevent communication between them. The first valve tributary flow path 50 is located on one side of the partition wall 54, and one end of the first valve tributary flow path 50 is connected to the main flow path 14. The second valve tributary flow path 52 is located on the other side of the partition wall 54, and one end of the second valve tributary flow path 52 is connected to the post-valve main flow path 48. The second joint 28 is modified so as to be connected to one end of the post-valve main flow path 48. The control valve 46 has a valve inlet 56 and a valve outlet 58, and the control valve 46 is provided in the pipeline body 10, with the valve inlet 56 connected to the first valve branch path 50 and the valve outlet 58 connected to the second valve branch path 52.

[0017] With the above structure, fluid entering the main flow path 14 from the first joint 26 first passes through the filter 30, then enters the control valve 46 via the first valve tributary flow path 50, then enters the post-valve main flow path 48 via the second valve tributary flow path 52, and finally is discharged from the second joint 28. As described above, some fluid enters the sensor 12 from outside the filter 30 via the first sensor tributary flow path 16, and the sensor 12 detects the fluid flow rate and generates a detection signal accordingly, which is sent to the processor 60. The processor 60 controls the control valve 46 in response to the detection signal to adjust the flow rate of the fluid discharged from the valve outlet 58 of the control valve 46 so that the fluid in the post-valve main flow path 48 has a predetermined flow rate.

[0018] As described above, a pressure chamber 40 and an airway 42 are also provided within the main conduit body 10, and a portion of the fluid in the main flow path 14 enters the pressure chamber 40 through the airway 42, thereby maintaining a similar pressure inside and outside the sensor 12 and reducing the probability that the sensor 12 will be damaged by high-pressure fluid. [Explanation of symbols]

[0019] 1 Mass flow meter 2 Mass flow controller 10 Pipe body 12 sensors 14 Main channel 16 First sensor branch 18 Second sensor branch 20 Containment Room 22 Channel entrance 24 Flow path outlet 26 First Joint 28 Second Joint 30 filters 32 Airtight Ring 34 Closure 36 Inlet gas nozzle 38 Outlet gas nozzle 40 Pressure Chamber 42 Airway 44 O-ring 46 Control Valve 48 Main flow path after valve 50 First valve branch 52 Second valve branch 54 Bulkhead 56 Valve inlet 58 Valve outlet 60 processors

Claims

1. a conduit body having a main flow path, a first sensor branch flow path, a second sensor branch flow path, and a storage chamber, wherein both ends of the first sensor branch flow path and the second sensor branch flow path are connected to the main flow path and the storage chamber, respectively, and a filter is provided in the main flow path; a sensor having an inlet gas nozzle and an outlet gas nozzle, the sensor being disposed in the chamber, the inlet gas nozzle being connected to the first sensor tributary channel and the outlet gas nozzle being connected to the second sensor tributary channel, and measuring a flow rate of a fluid by causing a portion of the fluid that has passed through the main channel to enter the sensor via the first sensor tributary channel and then return to the main channel via the second sensor tributary channel; A mass flow meter comprising: The conduit body is further provided with a pressure chamber and an airway, the pressure chamber is connected to the storage chamber, and the airway is connected to the pressure chamber and the main flow path, respectively, and a portion of the fluid that has passed through the main flow path enters the pressure chamber via the airway, thereby matching the pressure inside and outside the sensor.

2. 2. The mass flow meter according to claim 1, wherein the volume of the storage chamber is larger than that of the sensor, and the space between the sensor and a side wall of the storage chamber forms the pressure chamber.

3. 2. The mass flow meter of claim 1, wherein the first sensor tributary has a diameter larger than the sensor inlet gas nozzle, resulting in a space between the inlet gas nozzle and a sidewall of the first sensor tributary forming the airway.

4. 3. The mass flow meter of claim 2, wherein an O-ring is installed at the sensor outlet gas nozzle to provide an airtight seal between the pressure chamber and the second sensor branch.

5. The mass flow meter of claim 1 , further comprising a closure, the closure covering the chamber in which the sensor is disposed.

6. a conduit body having a main flow path, a first sensor branch flow path, a second sensor branch flow path, a storage chamber, a post-valve main flow path, a first valve branch flow path, and a second valve branch flow path, wherein both ends of the first sensor branch flow path and the second sensor branch flow path are connected to the main flow path and the storage chamber, respectively, one end of the first valve branch flow path is connected to the main flow path, and one end of the second valve branch flow path is connected to the post-valve main flow path, and the main flow paths are provided with a filter; a sensor having an inlet gas nozzle and an outlet gas nozzle, the sensor being disposed in the accommodation chamber, the inlet gas nozzle being connected to the first sensor branch channel and the outlet gas nozzle being connected to the second sensor branch channel, wherein a portion of the fluid that has passed through the main channel enters the sensor via the first sensor branch channel and then returns to the main channel via the second sensor branch channel, thereby detecting a flow rate of the fluid; a control valve having a valve inlet and a valve outlet, the control valve being disposed in the pipeline body, the valve inlet being connected to the first valve branch passage and the valve outlet being connected to the second valve branch passage, such that fluid in the main passage enters the control valve through the first valve branch passage and then enters the main passage after the valve through the second valve branch passage, and the control valve adjusts the flow rate of fluid flowing out of the valve outlet in accordance with the flow rate detected by the sensor; 1. A mass flow controller comprising: The conduit body is further provided with a pressure chamber and an airway, the pressure chamber being connected to the storage chamber, and the airway being connected to the pressure chamber and the main flow path, respectively, and a portion of the fluid that has passed through the main flow path enters the pressure chamber via the airway, thereby matching the pressure inside and outside the sensor.

7. 7. The mass flow controller according to claim 6, wherein the volume of the storage chamber is larger than that of the sensor, and the space between the sensor and the side wall of the storage chamber forms the pressure chamber.

8. 7. The mass flow controller of claim 6, wherein the diameter of the first sensor tributary is larger than the sensor inlet gas nozzle, resulting in a space between the inlet gas nozzle and a sidewall of the first sensor tributary defining the airway.

9. 9. The mass flow controller of claim 8, wherein an O-ring is installed at the outlet gas nozzle of the sensor to provide an airtight seal between the pressure chamber and the second sensor tributary.

10. 7. The mass flow controller of claim 6, further comprising a closure, the closure covering the chamber in which the sensor is disposed.

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