Mass Flow Meter

Abstract

The present invention relates to a mass flow meter comprising a valve housing having a passage for fluid flow, a sensor unit that detects the fluid flow rate and converts it into an electrical quantity, and a flow control unit that controls the fluid flow rate, wherein a plunger housing containing a plunger that moves up and down by the electromagnetic force of a core is connected to the valve housing, the core is located at the top of the plunger housing, and the top of the plunger housing where the core is located is open, and the open top of the plunger housing is closed by contact with the core, thereby enabling consistent performance regardless of the core fastening torque.

Description

Technology Field

[0001] The present invention relates to a mass flow meter, and more specifically, to a mass flow meter comprising a plunger that moves up and down by the magnetic force of a core, wherein the core is located at the open upper portion of the plunger housing and the core closes the open upper portion of the plunger housing, thereby enabling consistent assembly regardless of the core fastening torque and enabling consistent performance. Background Technology

[0002] Mass flow controllers (MFCs) have been used in semiconductor processes and other applications to precisely control the mass flow of fluids, such as toxic or highly reactive fluids. Recently, their application has expanded to industrial plants, where they are also used for flow indication and control purposes for fluids such as air and oxygen.

[0003] Mass flowmeters are classified into direct mass flowmeters, distinguished by hot wire, Coriolis, differential pressure, and angular momentum types, and indirect mass flowmeters, distinguished by combination types of flowmeters and densimeters detecting PQ2, combination types of flowmeters and densimeters detecting Q, combination types of flowmeters and flowmeters detecting PQ2 and Q, temperature and pressure compensation types, or temperature compensation types.

[0004] A mass flow meter is illustrated in FIGS. 1 and 2 as a prior art.

[0005] This is a drawing disclosed in Figures 1 and 3 of Registered Patent Publication No. 2157826. The mass flow meter includes a valve housing having a passage (inlet, outlet) for fluid flow, a sensor unit that detects the fluid flow rate and converts it into an electrical quantity, and a flow control unit that controls the discharged fluid flow rate. The flow control unit is equipped with a plunger that moves up and down by magnetic force, such as a core or a solenoid, to open and close the flow path.

[0006] As shown in FIG. 1, such a plunger (500) has its side and upper surfaces blocked by a plunger housing, and its lower surface is in contact with a flow path formed in a valve housing, etc.

[0007] And as shown in FIG. 2(b), when a magnetic force is formed in the core (100) located above the plunger (500) and the plunger (500) moves upward within the plunger housing, the fluid path below the plunger (500) is opened and fluid flows, and as shown in FIG. 2(a), when no magnetic force is formed in the core (100), the plunger (500) returns to its original position due to gravity or the elastic force of a spring and closes the fluid path.

[0008] It can be said that the degree of opening of the flow path and the flow rate are determined by the upward and downward movement of the plunger (500) according to the magnetic force of the core (100).

[0009] In determining the extent to which the magnetic force of the core (100) affects the plunger (500), the distance between the core (100) and the plunger (500) is significantly important. If the distance between the core (100) and the plunger (500) is long, the travel distance of the plunger (500) becomes shorter even with the same magnetic force, and if the distance between the core (100) and the plunger (500) is short, the travel distance of the plunger (500) becomes longer even with the same magnetic force, which can be a reason why a mass flow meter of the same model cannot perform consistently.

[0010] As shown in FIG. 1, a plunger housing (200) coupled to a valve housing (300) was located between the conventional core (100) and the plunger (500).

[0011] Since fluid exists within the plunger housing (200), it naturally forms a closed shape that is isolated from the outside. A plunger (500) is positioned inside the plunger housing (200), which has a cylindrical upper surface (housing membrane), with a gap between it and the upper surface (housing membrane), and a core (100) is positioned directly on the closed upper surface (housing membrane). Based on the magnetic force of the core (100), the plunger (500) moves up and down between the upper surface (housing membrane) and the gap, thereby opening or closing the fluid flow path.

[0012] However, in the prior art, the core (100) is installed by fastening it to contact the housing membrane of the plunger housing (200), but there was a point where the fastening torque varied depending on the worker during the fastening process.

[0013] When the fastening torque is strong, the core (100) comes into strong contact with the housing membrane, causing a portion of the housing membrane to sag. As a result, the gap between the plunger and the housing membrane (distance the plunger moves, stroke) decreases by the amount the housing membrane sags. Conversely, when the fastening torque is weak, the housing membrane does not sag, but the magnetic force pulling the plunger becomes weak.

[0014] There was a problem where consistent quality could not be achieved across products of the same model, as performance degradation occurred whether the tightening torque was strong or weak.

[0015] The gap (stroke) between the plunger and the housing membrane must be finely controlled; however, a tightening torque slightly larger or smaller than the specified torque causes sagging of the housing membrane and insufficient magnetic force of the core, making it impossible to accurately control the flow rate, which is the most critical performance aspect of a mass flow meter.

[0016] In addition, the housing film located in the middle where the magnetic force is transmitted from the core (100) to the plunger (500) was formed like a thin film of about 0.3 mm, which had the problem that it could easily deform due to the tightening torque of the core (100) described earlier, and also had the problem that it was difficult to manufacture itself. Of course, it would be possible to increase the thickness, but there was a limit to increasing the thickness because there was a problem with the magnetic force from the core being transmitted to the plunger. Prior art literature

[0017] (Prior Art 001) Registered Patent Publication No. 10-2157826 The problem to be solved

[0018] To solve such problems, the present invention provides a mass flow meter that is simple to manufacture and enables consistent assembly regardless of the core fastening torque, in which a plunger housing accompanies a plunger that moves up and down by the electromagnetic force of a core is open at the top of the plunger housing, and the core directly closes the open top of the plunger housing. means of solving the problem

[0019] To solve the above-mentioned problem, the present invention provides a mass flow meter comprising a valve housing having a passage for fluid flow, a sensor unit that detects the fluid flow rate and converts it into an electrical quantity, and a flow control unit that controls the fluid flow rate, wherein a plunger housing containing a plunger that moves up and down by the electromagnetic force of a core is connected to the valve housing, the core is located at the top of the plunger housing, and the top of the plunger housing where the core is located is open.

[0020] Here, it is desirable for the upper part of the open plunger housing to be closed by contact with the core.

[0021] In addition, a groove is formed on the upper part of the plunger housing where a seal can be positioned, and it is preferable that a seal be positioned between the core and the upper part of the plunger housing so that the core and the upper part of the plunger housing can come into contact with each other and be sealed.

[0022] In addition, it is preferable that the core includes a core body portion and a cylindrical core protrusion protruding from the core body portion so as to be able to contact the upper part of the plunger housing at the lower part of the core body portion.

[0023] In addition, the core has a cylindrical shape with a constant diameter, and the lower surface of the cylindrical core may come into contact with the upper surface of the open plunger housing. Effects of the invention

[0024] The mass flow meter according to the present invention can achieve consistent performance by directly closing the core at the top of the open plunger housing, thereby enabling consistent assembly regardless of the core fastening torque.

[0025] In addition, the effect of improving productivity is achieved by not forming a thin housing film on the plunger housing; however, the effects of the present invention are not limited to this literal description but include everything that a person skilled in the art can infer from the present invention. Brief explanation of the drawing

[0026] FIG. 1 is a cross-sectional view of a mass flow meter that includes a valve housing, a sensor unit that detects flow rate and converts it into an electrical quantity, and a flow control unit as part of the prior art. FIG. 2 is a cross-sectional view of a mass flow meter according to FIG. 1, where (a) shows a state in which no magnetic force acts on the core, and (b) shows a state in which a magnetic force acts on the core. FIG. 3 is a cross-sectional view showing the operating state of a plunger in a mass flow meter according to one embodiment of the present invention. Figure 4 is an enlarged cross-sectional view of the plunger portion of the mass flow meter of Figure 3. FIG. 5 is a cross-sectional view showing the operating state of a plunger in a mass flow meter according to another embodiment of the present invention. Specific details for implementing the invention

[0027] An embodiment of the present invention will be described with reference to the attached drawings.

[0028] The embodiments are intended to facilitate the explanation of the present invention and the present invention is not limited thereto. The terms in this specification are for the purpose of explaining the embodiments, and terms such as "include" or "have" mean that a configuration exists. The drawings are illustrated for illustrative purposes only and are not drawn to scale.

[0029] The mass flow meter of the present invention, like the prior art, comprises a valve housing including an inlet and an outlet to allow fluid to flow, a sensor unit that detects the flow rate of the fluid passing through the valve housing and converts it into an electrical quantity, and a flow control unit that controls the flow rate discharged through the outlet.

[0030] A flow control unit is installed in a valve housing and includes a plunger (500) with a core (100) located at the top and a plunger housing (200) provided in a form that surrounds the plunger (500) around the plunger (500), and controls the opening through which fluid passes by moving the plunger (500) up and down within the plunger housing (200) according to the operation (excitation) of the core (100).

[0031] FIG. 3 is a drawing showing the plunger operating state according to one embodiment of the present invention, and FIG. 4 is an enlarged drawing of the plunger portion, and the present invention is explained using these.

[0032] As previously explained, the mass flow meter of the present invention comprises a valve housing, a plunger (500) that controls the opening through which fluid passes, and a plunger housing (200) that surrounds the plunger (500) and forms a fluid space inside. That is, a fluid inlet and an outlet are formed in the valve housing, and a flow sensor unit detects the flow rate of the fluid and converts it into an electrical quantity, and the plunger (200) moves up and down according to the excitation of the core (100) to control the flow rate of the discharged fluid.

[0033] A plunger housing (200) that accommodates a plunger (500) inside has a first space (250), a second space (260), etc. formed therein through which fluid flows, and the plunger housing (200) must be sealed from the outside so that the fluid flowing inside does not leak out to the outside.

[0034] Conventionally, the plunger housing (200) itself had its side and top surfaces sealed, but in the present invention, the top of the plunger housing (200) is open, and the core (100) is positioned on the open top to close the open top of the plunger housing (200).

[0035] The plunger housing (200) is empty so that a plunger (500) is positioned inside and is composed of a first plunger housing (210) having a cylindrical shape with a certain thickness and a certain diameter, and a second plunger housing (220) connected to the bottom of the first plunger housing (210) and having a larger diameter than the first plunger housing (210), wherein a core (100) contacts and closes the portion of the cylindrical shape of a certain thickness at the top of the first plunger housing (210).

[0036] A groove (240) in which a sealing (230) can be positioned may be formed on the upper part of the plunger housing (200), and the sealing (230) may be positioned in the groove (240) so that the core (100) and the upper part of the plunger housing (200) can come into contact with each other and be sealed.

[0037] When the plunger housing (200) and the core (100) are in surface contact, there is a possibility of fluid leakage, but a sealing (230) is positioned to maximize the sealing effect. When the plunger housing (200) is formed with a first plunger housing (210) and a second plunger housing (220), a groove (240) is formed on the upper part of the first plunger housing (210), and the thickness of the first plunger housing (210) must be such that the groove (240) can be formed and the core (100) in contact therefrom can be supported.

[0038] The core (100) includes a solid cylindrical core body (110) and a core protrusion (120) protruding from the core body (110) so as to close the open upper portion by contacting the upper portion of the plunger housing (200) at the lower portion of the core body (110).

[0039] The core protrusion (120) is also formed in a cylindrical shape, and the core protrusion (120) comes into contact with the sealing (230) located on the upper surface of the first plunger housing (210). However, the length of the core protrusion (120) protruding relative to the core body (110), the height occupied in the entire core (100), and the magnetic force exerted can be determined by taking into account the magnetic force.

[0040] Unexplained reference numeral 800 is a flow control unit housing (800) coupled to the plunger housing (200) in the plunger housing (200). This consists of a first flow control unit housing (810), a second flow control unit housing (820), and a third flow control unit housing (830).

[0041] As shown in FIG. 4, a second flow control unit housing (820) is in contact with the outside of the first plunger housing (210) forming the plunger housing (200), and a step of a certain thickness (t) is formed between the upper surface of the first plunger housing (210) and the upper surface of the second flow control unit housing (820) so that the upper surface of the second flow control unit housing (820) is higher.

[0042] The height (thickness) of the core protrusion (120) forming the core (100) is made equal to a certain thickness (t), and the outermost diameter of the core protrusion (120) is made equal to the outer diameter of the first plunger housing (210), so that the core protrusion (120) can be seated so as to be fitted between the upper surface of the first plunger housing (210) and the upper surface of the second flow control unit housing (820).

[0043] In this case, after the core (100) is installed, the upper surface of the core protrusion (120) and the second flow control unit housing (820) becomes flat without any step difference.

[0044] In this invention, the upper part of the plunger housing is open, and the core directly closes this open upper part of the plunger housing, enabling consistent assembly regardless of the core fastening torque, thereby ensuring consistent performance. Additionally, the magnetic force of the core is directly transmitted, which helps improve performance. Furthermore, the upper surface of conventional plunger housings is formed as a thin film, making manufacturing difficult; this difficulty can now also be resolved.

[0045] FIG. 5 shows the operating state of a plunger according to another embodiment of the present invention.

[0046] The core (100) has a cylindrical shape with a constant diameter, and the lower surface of the cylindrical core (100) can come into contact with the upper surface of the open plunger housing (200).

[0047] In the preceding embodiment, a protrusion (120) is formed on the core (100), and in this embodiment, the lower surface of the core (100) itself can be said to be in contact with the upper surface of the plunger housing (200). However, this can be determined by considering the magnetic force acting on the core (100) and the size of the plunger.

[0048] Meanwhile, there are various types of methods for opening and closing a flow path by raising and lowering the valve housing and plunger of a mass flow meter, and the present invention can be applied to any method in which a plunger and a plunger housing exist, and is not limited to a specific method.

[0049] Unexplained reference numeral 600 is a first spring (600) to which force is applied to return the plunger (500) to a basic position that closes the flow path, and unexplained reference numeral 700 is a second spring (700) to relieve contact with the core (100) when the plunger (500) rises.

[0050] The present invention is not limited by the disclosed embodiments and the accompanying drawings, and can be modified in various ways by those skilled in the art without departing from the technical spirit of the invention. Furthermore, the technical spirit described in the embodiments of the present invention may be implemented independently or two or more may be implemented in combination. Explanation of the symbols

[0051] 100 : Core 110 : Core body 120 : Core protrusion 200 : Plunger housing 210: 1st plunger housing 220: 2nd plunger housing 230 : Sealing 240 : Groove 250 : 1st space section 260 : 2nd space section 500 : Plunger 600 : 1st spring 700 : Second spring 800 : Flow control unit housing 810: First flow control unit housing 820: Second flow control unit housing 830 : Third flow control unit housing

Claims

Claim 1 A mass flow meter comprising a valve housing having a passage for fluid flow, a sensor unit that detects the fluid flow rate and converts it into an electrical quantity, and a flow rate control unit that controls the fluid flow rate, wherein a plunger housing (200) containing a plunger (500) that moves up and down by the magnetic force of a core (100) is connected to the valve housing, wherein the core (100) is located at the top of the plunger housing (200), and the top of the plunger housing (200) where the core (100) is located is open, and the core (100) comprises a core body portion (110); and a core protrusion portion (120) that protrudes outwardly from the core body portion (110) so as to be able to contact the top of the plunger housing (200) at the bottom of the core body portion (110). Claim 2 delete Claim 3 A mass flow meter according to claim 1, wherein a groove (240) in which a sealing (230) can be positioned is formed on the upper part of the plunger housing (200), and the sealing (230) is positioned on the upper part of the plunger housing (200) so that the core protrusion (120) and the upper part of the plunger housing (200) can come into contact with each other and be sealed. Claim 4 delete Claim 5 delete

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