A gas mass flow meter

Abstract

The utility model relates to a kind of gas mass flow meters.Valve seat is integrally-formed compact base, its top is equipped with a sunken installation area, at least part of the body of solenoid valve is contained in the sunken installation area;Valve seat interior is opened with three-stage passage that gradually decreases along the intake direction pipe diameter and sequentially communicates, jointly constitute a laminar flow steady flow passage;Capillary tube temperature difference sensor has import and export, its import is communicated with first channel by first capillary tube connection passage, its export is communicated with second channel by second capillary tube connection passage;The end of third channel is connected to the import of solenoid valve, the export of solenoid valve is connected to a gas outlet channel that is opened on valve seat;Third channel is as the gas inlet channel of solenoid valve, its length is greater than gas outlet channel.The purpose is to solve the following problems, the size of existing gas mass flow meter is larger, not suitable for space limited occasions, fluid flow is unstable, and the measurement accuracy is influenced, leakage error is larger.

Description

Technical Field

[0001] This utility model relates to the field of flow measurement equipment technology, and in particular to a gas mass flow meter. Background Technology

[0002] A gas mass flow meter is a precision instrument used to measure the mass flow rate of fluids, and it is widely used in industrial automation, medical equipment, semiconductor manufacturing, and other fields. With the increasing demands for industrial automation and precision control, higher requirements are being placed on the accuracy, stability, and integration of gas mass flow meters.

[0003] Traditional gas mass flow meters typically employ a thermal measurement principle, calculating flow rate by measuring the temperature change of the fluid as it passes through a heating element. One common measuring element is the capillary differential temperature sensor, which determines the fluid's mass flow rate by measuring the temperature difference across the capillary.

[0004] However, existing gas mass flow meters have the following technical problems: First, their overall structural size is relatively large, making them unsuitable for space-constrained applications and failing to meet the demands for miniaturization and integration. Second, their fluid flow stability is insufficient, especially when flow rate changes significantly, as flow field disturbances can significantly affect measurement accuracy. Third, their airtightness design is inadequate, resulting in substantial leakage errors. These issues limit the widespread use of gas mass flow meters in high-precision, miniaturized applications. Utility Model Content

[0005] The purpose of this invention is to solve the following problems: existing gas mass flow meters are too large to be suitable for space-constrained occasions, unstable fluid flow affects measurement accuracy, and leakage error is large.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] According to one aspect of this utility model, a gas mass flow meter is provided, including a valve seat, a capillary temperature difference sensor, a solenoid valve, and a housing. The valve seat is a compact, integrally formed base with a recessed mounting area on its top. At least a portion of the solenoid valve body is accommodated within this recessed mounting area. The valve seat has three channels inside, with the diameter decreasing sequentially along the inlet direction and connected in sequence, including a first channel, a second channel, and a third channel, which together form a single-layer flow stabilization channel. The capillary temperature difference sensor has an inlet and an outlet. Its inlet is connected to the first channel through a first capillary connecting channel, and its outlet is connected to the second channel through a second capillary connecting channel, allowing a portion of the gas flow to pass through the capillary temperature difference sensor. The end of the third channel is connected to the inlet of the solenoid valve, and the outlet of the solenoid valve is connected to an outlet channel formed on the valve seat. The third channel serves as the inlet channel of the solenoid valve, and its length is greater than that of the outlet channel.

[0008] Optionally, the air inlet end of the laminar flow stabilizing channel is provided with an axial sealing ring.

[0009] Optionally, the valve seat has an air inlet end with an integral or separate connecting flange, the connecting flange having an air inlet hole at its center and the inner hole being threaded.

[0010] Optionally, the thread is an internal thread structure, used to adapt to pipe external thread fittings of different specifications.

[0011] Optionally, the inner wall of the cover is formed with a vertical slot structure for snapping on at least one PCBA board; the cover is fitted onto the upper part of the valve seat and is positioned and installed with the PCBA board through the slot.

[0012] Optionally, the side wall of the housing is provided with a mounting hole for mounting an electrical connector; the side wall of the housing is provided with a limiting step, which is used to axially position the electrical connector inserted into the mounting hole.

[0013] Optionally, the electrical connector is an M12 connector for connection to an external control unit to enable power supply and signal communication.

[0014] Optionally, the diameter of the vertically arranged capillary connection channel is smaller than the diameter of the third channel.

[0015] Alternatively, the valve seat may be made of stainless steel or aluminum alloy.

[0016] The advantages of this invention are as follows: By adopting a compact valve seat design and embedding the solenoid valve within the valve seat, a compact structure is formed, significantly reducing the overall size of the gas mass flow meter and making it more suitable for space-constrained applications; the internal air inlet section of the valve seat is designed with a three-section structure, with the pipe diameter decreasing from large to small in a funnel shape, which is conducive to forming a stable laminar flow state and improving measurement accuracy; the solenoid valve, which has a larger leakage rate, is placed at the tail end, separating control and measurement, effectively reducing the impact of leakage errors on measurement; an axial sealing structure is adopted for the laminar flow stabilization channel, reducing leakage points; in addition, this invention also features a threaded adapter flange structure to adapt to various specifications of mounting threads; the housing adopts a slot-type design with limiting steps, making the appearance more aesthetically pleasing and ensuring minimal overall gaps. Compared with the prior art, the gas mass flow meter of this invention has significant improvements in structural compactness, measurement accuracy, leakage control, installation versatility, and appearance design. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a cross-sectional view of the gas mass flow meter described in this utility model;

[0019] Figure 2 This is a schematic diagram of the valve seat described in this utility model;

[0020] Figure 3 This is a schematic diagram of the structure of the cover described in this utility model.

[0021] In the diagram: 1. Valve seat; 101. Recessed installation area; 102. First channel; 103. Second channel; 104. Third channel; 105. Air outlet channel; 2. Capillary temperature difference sensor; 3. Solenoid valve; 4. Cover; 401. Slot; 5. First capillary connection channel; 6. Second capillary connection channel; 7. Sealing ring; 8. Adapter flange; 9. PCBA board; 10. Electrical connector. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Example 1:

[0024] like Figures 1-3 As shown, a mass flow meter includes a valve seat 1, a capillary temperature difference sensor 2, a solenoid valve 3, and a housing 4.

[0025] The valve seat 1 is a compact, one-piece molded base made of stainless steel or aluminum alloy. A recessed mounting area 101 is provided on its top, within which part of the solenoid valve 3 is housed. The valve seat 1 contains three sequentially connected, progressively decreasing diameter channels along the air inlet direction: a first channel 102, a second channel 103, and a third channel 104, which together form a laminar flow stabilizing channel. An axial sealing ring 7 is provided at the air inlet end of this laminar flow stabilizing channel to ensure that gas does not leak from the connection point, guaranteeing measurement accuracy.

[0026] The valve seat 1 has an integrated or separate adapter flange 8 at its air inlet end. The adapter flange 8 has an air inlet hole at its center and the inner hole is threaded. These threads are internal threads, which are used to adapt to external threaded pipe fittings of different specifications, thereby improving the versatility and adaptability of the mass flow meter.

[0027] The capillary temperature sensor 2 has an inlet and an outlet. Its inlet is connected to the first channel 102 via a first capillary connecting channel 5, and its outlet is connected to the second channel 103 via a second capillary connecting channel 6. This design allows a portion of the airflow to pass through the capillary temperature sensor 2, and the flow rate is calculated by measuring the temperature difference generated as the gas flows through the capillary. The diameter of the vertically arranged capillary connecting channel is smaller than the diameter of the third channel 104. This design ensures that only a suitable amount of gas flows through the capillary temperature sensor 2, while most of the gas still flows through the main channel, thus guaranteeing measurement accuracy without affecting the overall flow rate.

[0028] The end of the third channel 104 is connected to the inlet of the solenoid valve 3, and the outlet of the solenoid valve 3 is connected to an outlet channel 105 formed on the valve seat 1. The third channel 104 serves as the inlet channel of the solenoid valve 3, and its length is greater than that of the outlet channel 105. This design makes the gas flow more stable before entering the solenoid valve 3, reducing the impact of turbulence on measurement accuracy.

[0029] The inner wall of the housing 4 has a vertical slot 401 structure for snap-fitting at least one PCBA board 9. The housing 4 is fitted onto the upper part of the valve seat 1 and is positioned and installed with the PCBA board 9 through the slot 401. This design separates the electronic control part from the gas flow part, protecting the electronic components from gas corrosion and facilitating maintenance and replacement.

[0030] The housing 4 has mounting holes on its side wall for mounting an electrical connector 10. The side wall of the housing 4 also has a limiting step, which axially positions the electrical connector 10 when inserted into the mounting hole, preventing it from being installed too deeply or too shallowly. The electrical connector 10 is an M12 connector used to connect to an external control unit for power supply and signal communication, and features waterproof, dustproof, and interference-resistant properties.

[0031] When the mass flow meter is working, gas enters through the inlet port of the adapter flange 8 and splits into two paths after entering the laminar flow steady-flow channel: a small portion of the gas enters the capillary temperature difference sensor 2 through the first capillary connection channel 5, and then returns to the second channel 103 through the second capillary connection channel 6; the majority of the gas flows directly through the first channel 102, the second channel 103, and the third channel 104. The capillary temperature difference sensor 2 measures the temperature difference of the gas flowing through it, and the PCBA board 9 calculates the mass flow rate of the gas based on the temperature difference. The gas finally passes through the solenoid valve 3 to control the flow rate and is discharged from the outlet channel 105. The solenoid valve 3 can adjust its opening according to the control signal from the PCBA board 9 to achieve precise control of the gas flow rate.

[0032] This gas mass flow meter is compact, accurate, and easy to install, making it suitable for various industrial applications requiring precise control of gas flow, such as semiconductor manufacturing, medical equipment, and laboratory analytical instruments.

[0033] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A gas mass flow meter, comprising a valve seat, a capillary temperature difference sensor, a solenoid valve, and a housing, characterized in that: The valve seat is a compact, integrally formed base with a recessed mounting area on its top, where at least a portion of the solenoid valve body is accommodated. The valve seat has a three-section channel with a progressively decreasing diameter along the air intake direction and connected in sequence, including a first channel, a second channel and a third channel, which together form a single-layer flow stabilization channel; The capillary temperature difference sensor has an inlet and an outlet. Its inlet is connected to the first channel through a first capillary connecting channel, and its outlet is connected to the second channel through a second capillary connecting channel, so that a portion of the airflow can flow through the capillary temperature difference sensor. The end of the third channel is connected to the inlet of the solenoid valve, and the outlet of the solenoid valve is connected to an air outlet channel opened on the valve seat. The third channel serves as the air inlet channel for the solenoid valve, and its length is greater than that of the air outlet channel.

2. A gas mass flow meter according to claim 1, characterized in that: The air inlet end of the laminar flow stabilizing channel is equipped with an axial sealing ring.

3. A gas mass flow meter according to claim 1, characterized in that: The valve seat has an air inlet end with an integral or separate connecting flange. The connecting flange has an air inlet hole at its center and the inner hole is threaded.

4. A gas mass flow meter according to claim 3, characterized in that: The thread is an internal thread structure, used to adapt to external threaded pipe fittings of different specifications.

5. A gas mass flow meter according to claim 1, characterized in that: The inner wall of the cover is formed with a vertical slot structure for snapping on at least one PCBA board; the cover is fitted onto the upper part of the valve seat and is positioned and installed with the PCBA board through the slot.

6. A gas mass flow meter according to claim 5, characterized in that: The side wall of the housing has a mounting hole for mounting an electrical connector; the side wall of the housing has a limiting step for axially positioning the electrical connector inserted into the mounting hole.

7. A gas mass flow meter according to claim 6, characterized in that: The electrical connector is an M12 connector, used to connect to an external control unit for power supply and signal communication.

8. A gas mass flow meter according to claim 1, characterized in that: The diameter of the first capillary connecting channel is smaller than the diameter of the third channel.

9. A gas mass flow meter according to claim 1, characterized in that: The valve seat is made of stainless steel or aluminum alloy.

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