JPS5895217A - Mass-flow flow meter - Google Patents

Abstract

PURPOSE:To resolve the clogging of a sensor part and a by-pass part and facilitate the replacement and the maintenance of them, by attaching the sensor part and the by-pass part freely attachably and detachably to a flow meter body, to which a fluid transporting tube is connected, as one body. CONSTITUTION:Flow passages 4 and 5 connecting a fluid transporting tube 2 of the inlet side and a fluid transporting tube 3 of the outlet side are formed in a flow meter body 1, and a flow rate detecting sensor part 7 using a capillary tube 6 and a by-pass part 9 using a laminar flow element 8 are connected in parallel across said flow passages 4 and 5. When the sensor part 7 or the by- pass part 9 is clogged because of impurities of the fluid, the reaction of the fluid, or the like, the sensor part 7 and the by-pass part 9 are easily detached as one body together with an upper body 1A. Consequently, the replacement and the maintenance of these parts are facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention divides a fluid into a part of a flow rate detection sensor using a capillary tube and a bypass part using a laminar flow element, and also divides a fluid into a flow rate ratio between the part of the sensor and the bypass part. The present invention relates to a mass flow meter configured to measure the total flow rate of fluid based on.

In the above mass flow meter, conventionally, the first t! 2
1, a flow passage 2 is provided through the flow needle body 22.
3, a first-class element 24 formed by stacking a large number of disks each having grooves along the flow path direction is provided to constitute a bypass section 25, and a flow rate detection sensor 27 using a capillary tube 26 is installed in the bypass section. 25, and connect the flow meter main body 22 in parallel to the fluid inlet III; The structure is such that it is attached via β0.

However, in a mass flow meter, the sensor part 27
The capillary tube 26 or the laminar flow element 24 of the bypass section 25 may be clogged by impurities in the fluid, or the capillary tube 26 or the laminar flow element 24 may become clogged due to reaction with the fluid, and the sensor part 27 may be clogged. However, in the bypass section 25, the entire device must be removed from the joint 30.30 of the transport pipe 28.29. obtain,
Not only was maintenance very poor, but the flow rate needle itself had to be replaced as well, which was disadvantageous in terms of cost.

Separately, since the bypass portion 25 is constructed in the flow path 23 itself that connects the fluid transport pipes 28 and 29, a large dead space is formed before and after the bypass portion 25, and therefore, different fluids are When used as a measurement target, it took time to replace the fluid and lacked responsiveness.

In view of the above circumstances, the present invention provides a mass flow rate that is useful in terms of use, making it possible to improve maintenance and quickly replace the fluid when changing the measurement target by making a very quick modification. The purpose is to provide a measurement system.

Embodiments of the present invention will be described below with reference to the drawings.

$2 In the mass flow needle shown in the figure, 1 is a flow meter main body, in which channels 4 and 5 are formed to connect a fluid transport pipe 2 on the inlet side and a fluid transport pipe 3 on the outlet side, and
A flow rate detection sensor part 7 using a capillary tube 6 and a bypass section 9 using a laminar flow element 8 are connected in parallel across the flow path 4.5.

The me meter main body 1 includes the sensor part 7 and the bypass part 9.
The upper flowmeter main body IA, which is connected in parallel with the fluid transport pipe 2,
3 is connected to the lower flow meter body IB,
A Q++ ring 10 is placed around the channels 4 and 5 of the divided portion.
10, connect the upper and lower main bodies IA and IB with bolts 11.
．． 11 for airtight connection.

As shown in FIG. 42, the sensor part 7 includes a capillary tube 6 bent in a U-shape, which is fixed to the upper main body IA with both ends communicating with the flow channels 4 and 5. The capillary tube 6 and the two sensor coils 12 and 13 wound thereon are entirely buried in a heat insulating material 14 such as closed polystyrene foam so as to be unaffected by the ambient temperature as much as possible. The flow measurement principle is based on the fact that the degree of cooling of the sensor coil 12 , 13 is proportional to the mass flow rate of the fluid flowing through the capillary tube 6 .

That is, the two sensor coils 12.13 form a bridge circuit together with two resistive elements (not shown), and this bridge circuit cools the sensor coils 12.13 through the flow of fluid. The variable resistance of the sensor coil 12.13 is arranged to generate an unbalanced voltage, so that the fluid flow through the sensor part 7 can be measured on the basis of this unbalanced voltage. be.

In Fig. 2, 15... are the terminals at both ends of the sensor coil 12, 13. To connect this terminal 15 to an external circuit, as shown in Fig. 4 (A), connect the terminal 15. This can be done via the lead wire 16 wound around the upper body IA, or as shown in FIG. This can be done via.

The bypass section 9, as shown in FIGS. 2 and 3,
It consists of a plurality of capillaries forming the laminar flow element 8 and a U-shaped member 18 that houses these capillaries,
The channel 4, through the hole 19.20 formed in the upper body IA.
5 and is fixed to the upper main body IA in a state in which the sensor portion 7 formed in the heat insulating material 14 is housed in a recess corresponding to the U-shaped space.

As the laminar flow element 8 of the bypass section 9, it is most preferable to use a capillary tube having the same characteristics as the capillary tube 6 used in the sensor part 7; For example, sintered metal,
A structure in which etched plates are arranged in multiple layers with their grooves facing the direction of the flow path. Historically, it has a structure in which a thin circular plate of, for example, 0.3 m has a very small hole diameter of about 0.3 to 1 Qum. It is also possible to use a so-called pore-aligning filter in which an infinite number of holes are formed.

According to the above configuration, the total flow rate of the fluid can be measured from the flow rate detected by the sensor part 7 based on the flow rate ratio in the sensor part 7 and the bypass part 9, and the The sensor part 7 or the bypass part 9 is
If a blockage occurs due to impurities in the fluid or reaction of the fluid, the sensor part 7 and the bypass part 9 can be integrated with the upper main body IA while the lower main body IB remains connected to the transport pipes 2 and 3. PI! J can be simply removed and maintenance can be easily performed on them.

Furthermore, the direct communication part of the sensor part 7 and the bypass part 9 with the flow path 4.5 can be formed independently of the communication part of the transport pipe 2.3. The flow path in the communication part can be set to the minimum necessary,
In other words, the dead space in the flow path can be reduced, fluid replacement can be quickly performed when measuring a different type of fluid, and responsiveness can be improved.

Historically, by incorporating the bypass s9 into the U-shaped space of the sensor part 7, the entire flowmeter can be constructed compactly, and by locating both parts 7 and 9 in the same room, the environment can be reduced. It is easy for both 7 and 9 to respond simultaneously to changes in the flow rate (this has the advantage of reducing flow rate errors).

FIG. 5 shows a first modified structure of the present invention. This thing is
In the sensor part 7 and the bypass part 9 that are made into a unit and are detachably attached to the lower body IB, the bypass part 9 is further detachably connected to the upper body IA with bolts, and the connecting part is provided with a bolt. HaQ IJ song 1
The sensor part 7 or the bypass part 9 can be replaced separately, making it highly economical.

FIG. 6 shows a second modified structure, in which the sensor part 7 and the bypass part 9 are arranged side by side on one base @ 22,
With the sensor part 7 and the bypass part 9 connected in parallel to each of the flow paths 4 and 5, the board 22 is attached to the flow meter main body 1.
It is removably bolted to the

As described above in detail in the embodiments, the present invention allows the sensor part and the bypass part to be integrally and detachably attached to the flow needle main body while the fluid transport pipe remains connected to the flow needle main body. It is easy to maintain the sensor part and the bypass part to remove blockages and to replace them. Moreover, the communication part of the sensor part and the bypass part to the flow path is the same as the communication part of the fluid transport pipe to the flowmeter body. Since they are formed in unrelated positions, the diameter of the flow path in the communication part of the transport pipe can be made small, that is, it can be set in the dead space before and after the sensor part and the bypass part, and different types can be formed. Fluid replacement can be performed quickly when measuring fluids such as
Furthermore, as explained in the embodiment, when the bypass part is built into the U-shaped space of a part of the sensor, not only does the entire device become more compact, but also the part of the sensor and the bypass part are protected against changes in the environment. This has the advantage that it becomes easier to respond simultaneously, and as a result, errors become smaller.

[Brief explanation of drawings]

Fig. 1 is a broken side view of a conventional structure, Fig. 2 and subsequent figures show embodiments of the present invention, Fig. 2 is a broken side view, Fig. 3 is a vertical sectional view of a part of the sensor, and Fig. IJ4 (A) ( B) is a diagram showing each pair of lead wires for connecting the terminal of the sensor coil and an external circuit, and FIG. 5 and FIG. 6 are a longitudinal sectional view and a perspective view, respectively, of the modified structure. 1...Flowmeter body, 2.3...Fluid transport pipe, 6...
・Capillary tube, 7... Part of sensor, 8... Laminar flow element, 9
...Bypass section.

Claims (1)

[Claims] ■ The fluid is divided into a part of the flow rate detection sensor using a capillary tube and a bypass part using a laminar flow element, and the fluid is divided into a part of the flow rate detection sensor using a capillary tube and a bypass part using a laminar flow element, and the fluid is divided based on the flow rate ratio of the part of the sensor and the bypass part. In a mass 70 meter configured to measure the total accumulated amount of
A mass flow meter characterized in that a part of the sensor and a bypass part are integrally and detachably attached to a needle body to which a fluid transport pipe is connected. (2) The mass flow meter according to claim 0, characterized in that a capillary tube having the same or almost the same characteristics as the capillary tube of the part of the sensor is used as the laminar flow element of the bypass section. (2) The sensor part and the bypass part are formed in a U-shape when viewed from the II+ side, and the bypass part is built into the U-shaped space of the sensor part. 0 or the mass flow meter according to item 0.