JPS6328244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a branch flowmeter having a structure with excellent measurement accuracy and durability.

An orifice plate is provided inside the main channel, and a branch channel is provided that spans the upstream and downstream portions of the main channel by sandwiching this orifice plate, and a flow rate measuring mechanism with a desired rotational structure is placed in this branch channel to allow the flow to flow within the branch channel. 2. Description of the Related Art Divided flowmeters have been known for a long time, in which the flow rate measurement mechanism is activated by a diverted fluid, so that the flow rate of a fluid flowing through a main channel can be determined.

For example, in 1949 (Showa 24), ``Flow measurement and instruments'' was published by E&F, N, Spon Ltd. of London, England.
``Hydrometry'', printed in Warsaw, Poland, and published by Pergamon Press Company in 1960 (Showa 35)
(HYDROMETRY) describes a split-flow flowmeter with the structure shown in Figure 1.

That is, 1 has connection parts 2 and 3 at both ends which can be connected to fluid transport pipes (not shown), and a main flow path 5 having an orifice plate attachment part 4 approximately in the center thereof, and a main flow path 5 on the side of this main flow path 5. 7 is an orifice plate provided in the orifice plate mounting portion 4; 8 is a rotary turbine; It is arranged at an intermediate position of the passage 6 near the entrance side. Reference numeral 9 denotes a nozzle plate capable of supporting the rotary turbine 8 , which is fixed near the opening of the branch channel 6 . Reference numeral 10 designates a plurality of nozzle holes drilled in the nozzle plate 9, and a plurality of nozzle holes are drilled in the same shape around the central axis so that the rotary turbine 8 can be rotated by the fluid flowing into the branch channel 6. Reference numeral 11 denotes a rotating shaft of a rotary turbine 8, which is connected to the housing 1 through a cladding tube 12 passing through the main flow path 5 of the housing 1, facing into a brake chamber 13 filled with brake fluid, and a rotary brake plate 14. It is connected with. Reference numeral 15 denotes a mechanical or electrical rotation detection device for detecting the rotation of the rotary brake plate 14.

In the branch flowmeter having the above configuration, when the fluid to be measured flowing in the direction of the arrow enters the main channel 5,
Under the set division ratio, a part of the fluid enters the division channel 6 and is injected from the nozzle hole 10 of the nozzle plate 9, giving the rotating turbine 8 a torque proportional to the square of the flow rate and the fluid density, as described later. . The rotary turbine 8 to which the torque has been applied has its rotary shaft 11 connected to the rotary brake plate 14 in the brake chamber 13 so that the rotational speed is 2.
Since it is balanced by receiving a braking torque which is proportional to the brake fluid density and the braking fluid density, the divided flow rate is proportional to the rotational speed and proportional to the square root of the braking fluid density and the fluid density ratio. Furthermore, the relationship between the branch flow rate and the main flow rate can be determined by determining the rotation speed of the rotating turbine if the above-mentioned braking fluid density and fluid density are constant and the orifice coefficient ratio of the branch flow path part and the main flow path part does not change. The flow rate can be determined by

Regarding such long-known split-flow flowmeters, structures shown in FIGS. 2 and 3 have recently been seen.

The structure shown in Fig. 2 is disclosed in JP-A-53-75964 (Japanese Patent Application No. 51-150313), and the structure shown in Fig. 3 is an improved version of the structure shown in Fig. 2. -42172 (Japanese Patent Application No. 52-108365).

Next, each figure will be explained. Components that are the same as those in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

First, the branch flowmeter shown in Fig. 2 has a branch flowmeter 6.
The structure is characterized in that a turbine chamber 16 is formed in the turbine chamber 16, and a rotary turbine 8 is disposed within the turbine chamber 16 so as to be able to rotate in response to the tangential force of the flow of the divided fluid flowing through the divided flow path 6.

On the other hand, in the split flow meter shown in FIG. 3, a nozzle plate 9 having the structure shown in FIG. The turbine 8 is characterized in that the turbine 8 is rotated by the divided fluid injected through the nozzle holes 10 of the nozzle plate 9.

However, in any of the branch type flowmeters shown in FIGS. 1 to 3, the branch member a forming the branch channel 6 has a separate structure from the casing 1 in which the main channel 5 is bored, and the connection point between the two is This necessarily necessitates the intervention of a sealing member b such as a gasket.

Further, the above-mentioned known branch flowmeter is generally used for measuring high temperature fluids such as steam, and the main channel 5 and the branch channel 6 are members of separate structure, that is, the housing 1 and the branch member a. Since they are separated through the sealing member b, there is a disadvantage that the low flow rate characteristics are deteriorated due to the temperature gradient that occurs at the connection portion. The reason is explained below.

(i) As mentioned above, the rotational torque T _T received by the turbine wheel 8 is the braking torque received by the rotary brake plate 14.
Equal to T _D. Rotating torque T _T and braking torque T _D
is expressed by the following equation.

T _T =F _T r _T =K _T Γ _G q ²・γ _T ...() T _D =F _D・r _D =K _D Γ _W N ²・γ _D ...() r _T : Turbine wheel nozzle Part radius r _D : Average radius of the brake blade where K _T : Proportional constant F _T : Turbine wheel driving force K _D : Proportional constant F _D : Braking force Γ _G : Fluid density Γ _W : Braking fluid density q : Divided flow rate N: Turbine wheel rotation speed K: Constant Because () = () From equation (), it can be seen that the flow rate passing through the branch channel 6 is proportional to the square root of the ratio of the fluid density in the brake chamber 13 to the density of the measured fluid and the rotational speed of the rotary brake plate 14.

(ii) Next, the flow rate Q _p of the main flow path 5 and the flow rate q of the branch flow path 6 are: However, α _p , α _g : Orifice coefficients of the main flow path 5 and branch flow path 6 K _p , K _q : Steam expansion coefficients of the main flow path 5 and branch flow path 6 are also products of passing areas. Therefore, if the fluid density Γ _G is constant Q _p /g=αoKo/α _g K _g = constant (However, Γ _G is constant)...(
).

As shown in (i) and (ii) above, in a split flow meter,
For accurate weighing, formulas () and () must be applied correctly.

However, in the conventional split flow meter described above, the split flow member a and the housing 1 of the main flow path 5 are connected via the seal member b such as a packing, so the heat conductivity of the seal member b is poor and the flow split member A temperature drop in the fluid passing through a is unavoidable. Therefore, the enthalpy decreases, the degree of dryness decreases, the specific volume decreases, and the shunt flow also decreases. According to experiments, for saturated steam of 5.5 kg/cm ² at a room temperature of 26°C, there was no temperature difference between the main flow section and the branch section at 100% flow rate with and without packing, but around 30% flow rate there was a temperature difference of about 2.5
The diversion section was low. As a result, as shown in FIG. 4, when the flow rate becomes small, the measurement accuracy rapidly decreases as shown by the dotted line.

One of the characteristics of this invention is that it has been achieved by paying attention to the points mentioned above, and it is possible to form a branch channel integrally with a housing structure provided with a main channel, and to prevent sealing members such as packing. It is an object of the present invention to provide a branch type flowmeter that prevents deterioration of heat conduction due to interference and has high flow rate accuracy even when the flow rate is small as shown by the solid line in FIG.

Further, when examining the conventional split flow meter described above, the rotary turbine 8 has a structure in which the rotary turbine 8 is disposed in the split flow path 6 in a separate structure from the brake chamber 13.
In other words, since the brake chamber 13 is attached to the housing 1 through a separate work process from the attachment device for the rotary turbine 8, the rotary brake plate 14 of the brake chamber 13 and the rotary turbine 8 are integrated by the rotary shaft 11. It was extremely difficult to obtain accurate centering during assembly and manufacturing. Furthermore, even if the bearing is installed accurately, the centering structure may become biased due to long-term use, making it impossible to perform accurate measurements and causing the bearing to wear more quickly.

This invention was made by paying attention to the points mentioned above, and includes a brake chamber including a rotary brake plate, a rotary shaft, a rotary turbine, a cladding tube through which the rotary shaft passes, and a cladding tube attached to the cladding tube. The turbine measurement unit body is constructed by integrally combining the holder including the nozzle plate, and the turbine measurement unit body can be integrated with the housing by inserting and fixing the rotating turbine and the nozzle plate side from one side of the branch channel. The purpose of this invention is to obtain a novel flowmeter with excellent durability by ensuring accurate centering of a rotating turbine, a rotating brake plate, and a rotating shaft, and preventing deterioration of accuracy.

Two embodiments of this invention will be described below with reference to FIG. 5 and subsequent figures. Components that are the same as those of the conventional example are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

Reference numeral 17 designates a flange portion of the turbine measuring unit body A, which is brought into contact with an opening 18 leading to the turbine chamber 16 of a branch channel 6 formed integrally with the main channel 5, and is attached to the housing 1 via a gasket 19 with a screw or the like. stopper 20
It can be fastened with.

By the way, the turbine measurement unit body A includes a brake chamber 13 in which a rotary brake plate 14 filled with brake fluid is disposed, a rotation detection device 15 configured as appropriate for detecting the rotation of the rotary brake plate 14, and a rotation detecting device 15 configured to detect the rotation of the rotary brake plate 14. Board 1
4, a rotary shaft 11 whose lower end is rotatably supported, a rotary turbine 8 through which the rotary shaft 11 passes and is fixed to the upper end, and a nozzle hole 10 disposed directly below the rotary turbine 8. a short cladding tube 12 that protects the nozzle plate 9 and the rotating shaft 11;
A peripheral wall portion 21 that protrudes upward from the periphery of the nozzle plate 9 to protect the outer periphery of the rotating turbine 8 and is approximately equal in size to the inner wall of the turbine chamber 16.
and an O-ring 22 fitted onto the outer periphery of this peripheral wall portion 21 to provide an integral structure. Furthermore, the upper part of the outer periphery leading to the brake chamber 13 is provided with a desired casing structure, such as a heat dissipation fin 23 when measuring steam or the like that requires a heat dissipation structure as in the past.

Next, in the case that is provided with the main flow path 5 and is integrally provided with a branch flow path 6 that communicates with the main flow path 5, a fifth
Two types of casings 1: the embodiment shown in Figs. 6 and 6, and the embodiment shown in Figs. 7 and 8.
a and 1b are shown. One housing 1a has a configuration in which the main flow path 5 and the branch flow path 6 are bored in parallel, and the turbine chamber 16 is similarly provided in parallel to the main flow path 5, whereas the other case 1b has a main flow path 6. 5 and a turbine chamber 16 are out of phase by 90 degrees, and branch passages 6 communicating with the main passage 5 are opened at the upper and lower portions of the turbine chamber 16.

The turbine chamber 1 depends on whether the formation of the turbine chamber 16 is parallel or 90 degrees different from the main flow path 5.
Since the mounting positions of the rotary turbine 8 disposed in the rotary turbine 6 and the turbine measurement unit body A integrally provided with the rotary turbine 8 are changed, the flowmeters of both embodiments can be appropriately selected depending on the piping.

In the figure, reference numeral 24 indicates a bearing for the rotating shaft 11, and reference numeral 25 indicates a flow rate indicator.

Since the configuration is as described above, the turbine measurement unit body A, which has an integrated structure including the rotating turbine 8, the brake chamber 13, the cladding tube 12, the nozzle plate 9, etc., is installed in the turbine chamber in the branch passage 6 of the housings 1a and 1b. While sliding the O-ring 22 of the peripheral wall 21 of the nozzle plate 9 on the inner wall of the turbine chamber 16, insert the upper part of the nozzle plate 9 through the opening 18 of the nozzle plate 16, aligning the flange 17 with the end surface of the opening 18, and insert the gasket 19. It can be attached very simply by means of the stopper 20 via the .

In this way, the turbine measurement unit body A is installed along the inside of the turbine chamber 16, but before the rotary turbine 8 is inserted into the turbine chamber 16, the turbine measurement unit body A is assembled and manufactured in advance. Since accurate centering can be performed, there is no need to perform such centering adjustment during assembly work to the housing 1. In addition, since the branch channel 6 is provided in the housings 1a and 1b that are integrally structured with the main channel 5, the deterioration in thermal conductivity of the branch fluid flowing through the branch channel 6 that is caused by the connection of a conventional sealing member can be reduced. .

However, in this invention, an opening 18 for inserting the turbine measurement unit A is formed on one side of the turbine chamber 16 formed in the middle of the branch channel 6 instead of the branch channel 6, and the turbine chamber 16 is inserted through a packing 19. are connected in the same direction.

It is desirable to minimize the change in the density of the brake fluid in the brake chamber, and by inserting the measurement unit A through the packing 19, the heat transfer to the brake chamber A is reduced, which prevents the temperature of the brake fluid from rising. , the density change is reduced, which is the desired result.

Next, the configuration of the orifice 7 used in these embodiments will be explained. That is, the mounting plate 27 has an opening 26 communicating with the main flow path 5 of the casing 1 and has the orifice 7 fixed through the opening 26.
is inserted into the mounting portion 4 provided in the desired main flow path 5 and fixed in a fitted state, and the peripheral edge of the mounting plate 27 is fixed by the locking rods 28, 28 inserted diagonally from both sides of the outside of the housing 1. At the same time, a cover plate 29 is fixed and closed to the opening 26.

Therefore, the orifice 7 can be easily replaced with another orifice 7 having a different diameter depending on the type of fluid to be measured, flow velocity, etc., and can be easily cleaned.

This orifice configuration is the same as that proposed in Utility Application No. 118690/1983, which was already developed by the present applicant.

Although embodiments of the present invention have been described above, the present invention is not limited to the configuration of the embodiments described above.

As described above, the present invention is characterized in that a branch passage formed with an orifice interposed between the main passage is provided in a housing integral with the main passage, and an opening of a turbine chamber is formed in the middle of the branch passage. Since the integrated turbine measurement unit body is inserted through the flange portion and fixed with a stopper together with the gasket, it is possible to effectively measure saturated steam, high temperature steam, etc.

In addition, since there is no seal part at the branch point between the branch channel and the main channel, it reduces the deterioration of thermal conductivity and prevents the enthalpy from decreasing.At the same time, it prevents the specific volume from decreasing and ensures measurement accuracy in the low flow range. This has the effect of expanding the measurement flow range.

Furthermore, according to the present invention, the direction of flow in the main channel and the direction of the turbine chamber can be determined simply by inserting and fixing the turbine measuring unit body, in which the rotating turbine is accurately installed with centering in advance, into the turbine chamber of the branch channel. Since it can be easily attached to fluid equipment with various types of casings, it is easy to assemble and manufacture, which helps improve work efficiency, and has excellent durability without deteriorating accuracy.

Furthermore, the present invention can be used not only for measuring saturated steam but also for measuring other gas vapors and liquids, and the turbine measuring unit is basically configured such that a rotating turbine, a rotating shaft, and this rotating shaft are connected. It is sufficient to have an integrated structure that includes a braking chamber and a rotation detection device, and it goes without saying that the other external structure, size, presence or absence of attached parts, etc. can be freely selected from various conventionally used ones. .

[Brief explanation of the drawing]

Figure 1, Figure 2 A, B, and Figure 3 are explanatory cross-sectional views of flowmeters showing several examples of conventional examples, and Figure 4 is the flow rate percentage.
5 and 6 are a partially cutaway front view and a partially cutaway side view showing an embodiment of the flowmeter according to the present invention, and FIGS. 7 and 8 are graphs showing the relationship between the flowmeter and the measurement accuracy. A partially cutaway front view and a partially cutaway side view showing another embodiment of the present invention, FIG. 9 is an enlarged cutaway side view of the main part of the turbine measuring unit body, FIG. 10 is a plan view of the same, and FIG. 11 is a partially cutaway side view. FIG. 3 is a sectional view of a main part showing an orifice mounting structure. 1, 1a, 1b...housing, 5...main flow path, 6...
...Division channel, 7... Orifice plate, 8... Rotating turbine, 9... Nozzle plate, 10... Nozzle hole, 11... Rotating shaft, 12... Cladding tube, 13...
Braking chamber, 14... Rotating brake plate, 15... Rotation detection device, 16... Turbine chamber, 17... Flange section, 18... Opening section, 21... Surrounding wall section, 22...
O-ring, 23... Heat dissipation fin, a... Diversion member, b... Seal member, A... Turbine measurement unit body.

Claims (1)

[Scope of Claims] 1. A branch channel is provided for a main channel provided with an orifice and communicates with the upstream and downstream sides of the main channel by sandwiching the orifice, and the branch fluid flowing through the branch channel is connected to the branch channel. Proportional to the flow rate by rotating the installed rotary turbine and balancing the rotational torque of the rotary turbine with the braking torque using a rotary brake plate installed in a brake chamber connected to the rotary turbine through a rotating shaft. Find the rotation,
In a flowmeter in which the rotation is detected by a rotation detection device and the flow rate of the fluid flowing through the main channel can be determined, the main channel and the branch channel are provided in an integrated housing, and a turbine chamber is located in the middle of the branch channel. At the same time, an opening is bored on one side of this turbine chamber, and the rotating turbine, nozzle plate, rotating shaft, cladding tube,
A flowmeter comprising a turbine measurement unit integrally equipped with a brake chamber, a rotation detection device, etc., which is firmly fitted into the turbine chamber so that a rotating turbine can be disposed together with a nozzle plate in the turbine chamber. 2. The flowmeter according to claim 1, wherein the nozzle plate has an O-ring fitted to its peripheral wall to abut against the inner wall of the turbine chamber. 3. The flowmeter according to claim 1, wherein the turbine chamber central axis is integrally provided in a position parallel to the main flow path, and a turbine measuring unit is provided in the same direction as the turbine chamber. 4. The flowmeter according to claim 1, wherein the turbine chamber is integrally provided at a position where the central axis of the turbine chamber is different from the main flow path by 90 degrees, and a turbine measuring unit is provided in the same direction as the turbine chamber.