Thermal gas mass flow meter

Abstract

The utility model discloses a thermal type gas mass flow meter which comprises a sensor body, an inlet flow guide pipe, an outlet flow guide pipe and a display device, the inlet flow guide pipe and the outlet flow guide pipe are connected with two sides of the sensor body, and the display device is fixed on the sensor body. The display device comprises a display shell base fixed on the upper surface of the sensor and a display shell buckled on the display shell base, a hollow circular groove is formed in the top of the sensor body, the thermal probe is located in the circular groove, two probes of the thermal probe extend into the sensor body, the thermal probe is connected with the PCB control panel above through a wire, and the PCB control panel is connected with the display shell base through a wire. A colored crystal screen is arranged at the top of the display shell and connected with a PCB control board located below the colored crystal screen through a wire, and an aviation plug connector is arranged at the side end of the display shell. The thermal type gas mass flow meter is small in size, convenient to mount and dismount and stable in performance.

Description

TECHNICAL FIELD

[0001] The utility model belongs to flow monitoring technical field especially relates to a thermal type gas mass flowmeter. BACKGROUND

[0002] The thermal type flowmeter is the flow instrument based on the thermal diffusion principle, that is, the heat loss of the heating object is proportional to the flow of the fluid when the fluid flows through the heating object. The sensor of the series flowmeter has two standard RTDs. One is used as a heat source, and the other is used to measure the fluid temperature. When the fluid flows, the temperature difference between the two is linearly related to the size of the flow. Through microelectronic control technology, the relationship is converted into a linear output of the flow signal. The thermal type gas mass flowmeter is an instrument for measuring gas flow using the thermal diffusion principle, and is widely used in chemical industry, petroleum, natural gas, environmental protection monitoring and other fields.

[0003] Under the premise of meeting the basic functions, the compactness of the gas flowmeter is a current development trend. Some current flow sensor structures are complex and bulky, which are inconvenient to carry. How to design a small, compact, easy-to-install and stable gas mass flow sensor is a technical problem to be solved at present. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a small, compact, easy-to-install and stable gas mass flow sensor.

[0005] The utility model provides a thermal type gas mass flowmeter, the flowmeter includes: a sensor body, an inlet guide pipe and an outlet guide pipe connected to both sides of the sensor body, and a display device fixed to the sensor body, wherein the display device includes a display shell base fixed to the top surface of the sensor and a display shell buckled on the display shell base, a hollow circular groove is formed in the top of the sensor body, the thermal probe is located in the circular groove, two probes of the thermal probe extend downward into the sensor body, the thermal probe is connected to the upper PCB control panel through a wire, the top of the display shell is provided with a color crystal screen, the color crystal screen is connected to the lower PCB control panel through a wire, and the side end of the display shell is fixed with a navigation plug connector.

[0006] Further, the top of the thermal probe is a probe main body in the shape of a cylinder, the probe main body is just placed in the circular groove, the lower part of the probe main body is fixedly connected with the probe, the wire is connected to the top of the probe main body, and a rectangular probe pressing plate is further arranged above the probe main body.

[0007] Further, the display shell base comprises a bottom plate and a containing groove above the bottom plate, screw holes are arranged at four corners of the bottom plate, the display shell base is fixed on the top of the sensor body through screws, and the PCB control board is located in the containing groove.

[0008] Further, a circular hole is arranged in the middle of the probe pressing plate, a circular transition plate which is integrally formed with the probe main body and has a smaller diameter than the probe main body is arranged above the probe main body, the circular transition plate is arranged in the circular hole of the probe pressing plate, screw holes are arranged at four corners of the probe pressing plate, and the probe pressing plate is fixed on the top of the sensor body through screws and presses the thermal probe.

[0009] Further, a screen sealing gasket is arranged outside the color crystal screen.

[0010] Further, the two probes of the thermal probe are on the same flow path as the inlet flow guide pipe and the outlet flow guide pipe, and the probes are close to the bottom wall of the sensor body but not in contact with the bottom wall.

[0011] Further, a button is arranged on the PCB control board, the button protrudes from the top of the display shell, and a button sealing gasket is arranged around the button.

[0012] Further, a block-shaped screen pressing plate is arranged below the color crystal screen.

[0013] The thermal gas mass flowmeter comprises a sensor body, a display device, a thermal probe, a PCB control board and a color crystal screen, the display device is arranged above the sensor body, the main body of the thermal probe is arranged flush with the top surface of the sensor body, the height in the vertical direction is reduced, and the overall structure is more compact, the PCB control board and the corresponding electronic circuit are sealed in the display shell and are limited, high waterproofness and stability are achieved, the stability of the thermal probe during work is ensured through the probe pressing plate, and when the thermal probe is installed and dismounted, the shell base does not need to be dismounted, and the assembly and disassembly of various modules are facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a schematic assembly view of the thermal gas mass flowmeter in the embodiment of the utility model.

[0015] Figure 2 It is a perspective view of the thermal gas mass flowmeter in the embodiment of the utility model.

[0016] Figure 3 It is a side view of the thermal gas mass flowmeter in the embodiment of the utility model. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model and not to limit the utility model.

[0018] It should be noted that the diagrams provided in the present embodiment only illustrate the basic concept of the utility model in a schematic manner.

[0019] The structure, proportion, size, etc. shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification for understanding and reading by those skilled in the art, and are not used to limit the limiting conditions that can be implemented by the utility model. Any modification of structure, change of proportion relationship or adjustment of size, which does not affect the effects that can be produced by the utility model and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed by the utility model.

[0020] The directions or position relationships such as "front", "rear", "left", "right", "middle", "longitudinal", "transverse", "horizontal", "inner", "outer", etc. cited in the present specification are based on the directions or position relationships shown in the drawings, and are only used to simplify the description, and are not used to indicate or imply that the devices or elements referred to must have a particular direction, be constructed and operated in a particular direction, and therefore cannot be understood as limiting the utility model. In addition, the terms "first" and "second" are only used for description purposes and cannot be understood as indicating or implying relative importance.

[0021] Referring to Figure 1 As shown in Fig. 3, the embodiment of the utility model provides a thermal type gas mass flowmeter for measuring the flow of gas, which comprises a sensor body 2 in the shape of a cuboid, the left and right sides of the sensor body 2 are communicated, the sensor body 2 is connected with an inlet flow guide pipe 1 and an outlet flow guide pipe 3 respectively on the left and right sides, and a display device for displaying parameters such as flow, flow rate and temperature is fixed on the sensor body 2, wherein the display device comprises a display shell base 4 fixed on the upper surface of the sensor body 2 and a display shell 15 with a containing space and buckled on the base, the shell and the base are made of ABS material, which has high strength, corrosion resistance and high temperature resistance.

[0022] The top of the sensor body 2 is provided with a circular groove, and the bottom of the thermal probe 5 is fixed with two vertical probes, which are located inside the sensor body 2. The two probes of the thermal probe 5 are on the same flow path with the inlet guide pipe 1 and the outlet guide pipe 3, which ensures that the gas can be sensed by the sensor, and the bottom of the probe does not contact the bottom wall of the sensor body 2, but is close to the bottom wall with a wider contact range. One is a speed sensor (RH), and the other is a temperature sensor (RMG). The speed sensor is heated, and the temperature sensor is used to measure the actual temperature of the gas. When the gas flows through the sensor, the speed sensor (RH) is heated and maintains a constant temperature difference (ΔT) higher than the gas temperature. As the gas flow rate increases, the gas flow will take away more heat, causing the temperature of the speed sensor to drop. In order to maintain a constant temperature difference, the heater needs to provide more energy. The greater the gas mass flow rate, the more significant the cooling effect, and the more energy required to maintain a constant temperature difference. By measuring the energy consumption of the heater, the mass flow rate of the gas can be accurately calculated.

[0023] The thermal probe 5 is connected to the upper PCB control board 10 through wires, and the PCB control board 10 is used to process the data detected by the thermal probe 5, and then display it on the display shell 15. The top of the display shell 15 is provided with a rectangular frame hole, which can accommodate the color crystal screen 11. The color crystal screen 11 is connected to the PCB control board 10 below it through wires. The side end of the display shell 15 is provided with a navigation plug 14 to ensure the reliability of electrical connection in extreme environments and provide stable power voltage for the PCB control board 10 and the thermal probe 5. The outer edge of the color crystal screen 11 is provided with a frame-shaped screen sealing gasket 12, which is sleeved on the outer edge of the color crystal screen 11 to reduce the vibration of the color crystal screen 11 and play a certain protection role. The screen sealing gasket is clamped or bonded with the empty frame on the top of the display shell.

[0024] The display shell base 4 includes a bottom plate and a rectangular receiving groove 41 above the bottom plate. The receiving groove 41 leaves a space on both sides of the bottom plate away from the edge of the bottom plate. The top of the receiving groove 41 is fixed with four clamping pieces 43 on both sides. The top of the clamping piece 43 is in the shape of a right triangle. This design makes the PCB control board 10 not easy to pop up, and plays a limiting role. Or the top of the clamping piece 43 is provided in the shape of a barb. The four corners of the bottom plate are provided with screw holes, and the display shell base 4 is firmly fixed on the top of the sensor body 2 through screws 6. The PCB control board 10 is located in the receiving groove 41. The bottom of the receiving groove (equivalent to the bottom of the base) is provided with a rectangular large hole to facilitate the installation of the thermal probe 5.

[0025] Specifically, the top of the thermal probe 5 is a probe body 51 in the shape of a cylinder, which is placed in a circular groove on the upper part of the sensor body 2, rather than being arranged in the base, reducing the height in the axial direction. Further, the circular groove 22 can be arranged in a stepped shape, so that the probe body 51 has a stepped support. The depth of the circular groove 22 can be consistent with the thickness (height) of the probe body 51, that is, the top surface of the probe body 51 is flush with the top surface of the sensor body 2. The lower part of the probe body 51 is fixedly connected to two probes, and the wires connected to the PCB control board 10 are arranged on the top of the probe body 51. Above the probe body 51, a rectangular probe pressing plate 7 is arranged in contact with the probe body 51. The rectangular probe pressing plate 7 is arranged in a rectangular large hole on the bottom of the base, and a circular hole is arranged in the middle of the probe pressing plate 7. Correspondingly, a circular transition plate 52 is arranged above the probe body 51, which is integrally formed with the probe body 51 and has a smaller diameter than the probe body 51. The vertical thickness is about 1-2 cm. The circular transition plate 52 is arranged in the circular hole in the middle of the probe pressing plate 7. The wires are led out upward from the circular transition plate 52. The length and width of the probe pressing plate 7 are greater than the diameter of the probe body 51. The probe pressing plate 7 is pressed on the upper surface of the probe body 51. Screw holes are arranged at the four corners of the probe pressing plate 7. The probe pressing plate 7 is fixed on the top of the sensor body 2 by locking screws 9 and pressed tightly against the thermal probe 5, preventing the thermal probe 5 from shaking during operation, maintaining the stability of the operation, and making the measurement result more accurate. In addition, since the thermal probe 5 is located below the display shell base 4, the design also has the advantage that the rectangular large hole on the bottom of the base can accommodate the pressing plate that presses the thermal probe 5. Without disassembling the display shell base 4, the thermal probe 5 can be replaced or checked, and the overall structure is more compact.

[0026] In this embodiment, the PCB control board 10 is provided with keys. The keys protrude from the top of the display shell 15. The keys are surrounded by a key sealing gasket 13, which is elastic and seals the keys. On the one hand, the key sealing gasket 13 protects the internal keys from being eroded by liquid, and the keys are more comfortable and shock-absorbing when pressed. Further, a block-shaped screen pressing plate 8 is arranged below the crystal screen 11 to strengthen the fixation of the crystal screen 11. The screen pressing plate 8 is made of PC (polycarbonate) material, which has high transparency and excellent mechanical properties, ensuring the stability of the crystal screen 11 during use. The two sides of the screen pressing plate 8 protrude upward to form two lap joints, and the width between the two lap joints is equal to the width of the crystal screen 11. The lap joints are engaged on the inner side of the display shell, further supporting and fixing the crystal screen 11.

[0027] In the embodiment, the inlet guide pipe 1, the sensor body 2, the outlet guide pipe 3, the thermal probe 5, the screw 6 and the probe pressing plate 7 are made of 304 stainless steel, which is corrosion resistant and high temperature resistant.

[0028] The technical features of the above embodiments can be combined arbitrarily, and to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered that it is within the scope of the description.

[0029] The above embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but it should not be understood as the limitation of the scope of the utility model patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, which belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A thermal gas mass flow meter characterized by, The flow meter comprises a sensor body, an inlet guide tube and an outlet guide tube connected to both sides of the sensor body, and a display device fixed to the sensor body, wherein the display device comprises a display shell base fixed to the upper surface of the sensor body and a display shell buckled to the display shell base, a hollow circular groove is formed in the top of the sensor body, a thermal probe is located in the circular groove, two probes of the thermal probe extend into the sensor body, the thermal probe is connected to an upper PCB control board through wires, a color crystal screen is arranged on the top of the display shell, the color crystal screen is connected to a lower PCB control board through wires, and a navigation plug is arranged at the side end of the display shell.

2. The thermal gas mass flow meter of claim 1, wherein, The top of the thermal probe is a probe body in the shape of a cylinder, the probe body is just located in the circular groove, the probes are fixedly connected to the lower part of the probe body, and the wires are connected to the top of the probe body. A rectangular probe pressing plate is further arranged above the probe body.

3. The thermal gas mass flow meter of claim 2, wherein, The display shell base comprises a bottom plate and a containing groove above the bottom plate, screw holes are arranged at the four corners of the bottom plate, the display shell base is fixed to the top of the sensor body through screws, and the PCB control board is located in the containing groove.

4. The thermal gas mass flow meter of claim 2, wherein, A circular hole is also formed in the middle of the probe pressing plate, a circular transition plate which is integrally formed with the probe body and has a smaller diameter than the probe body is further arranged above the probe body, the circular transition plate is located in the circular hole of the probe pressing plate, screw holes are arranged at the four corners of the probe pressing plate, and the probe pressing plate is fixed to the top of the sensor body and tightly presses the thermal probe through screws.

5. The thermal gas mass flow meter of claim 1, wherein, A screen sealing gasket is arranged outside the color crystal screen.

6. The thermal gas mass flow meter of claim 1 or 2, wherein, The two probes of the thermal probe are on the same flow path as the inlet guide tube and the outlet guide tube, and the probes do not contact the bottom wall of the sensor body but are close to the bottom wall.

7. The thermal gas mass flow meter of claim 1, wherein, Keys are arranged on the PCB control board, the keys protrude from the top of the display shell, and key sealing gaskets are further arranged around the keys.

8. The thermal gas mass flow meter of claim 1, wherein, A block-shaped screen pressing plate is arranged below the color crystal screen.

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