JPS5917366B2 - turbine meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine meter, in which a stirring blade is fixed to the body of an impeller rotatably supported between a pair of cone members held in a pipe, and the rotation of the stirring blade is It is an object of the present invention to provide a turbine meter configured to prevent dust contained in the fluid to be measured from entering into a space formed between the body of the impeller and the cone member due to the swirling flow thus generated. .

For example, a turbine meter that measures the flow rate of fluid such as city gas generally has a pair of cone members arranged facing each other on the upper and downstream sides of the pipe, and an impeller with blades embedded in the circumferential surface of the shaft. The impeller is attached to the pipe, and the impeller is rotated between the pair of cone members, and the flow rate of the fluid to be measured flowing through the pipe is measured from the number of rotations.

However, in this type of turbine meter, there is a gap between the impeller body and the upper and downstream cone members, so a part of the fluid to be measured flowing inside the pipe enters the cone member through this gap. As a result, there are disadvantages such as dust etc. in the fluid being measured may clog the bearing part, or dust may adhere to the body of the impeller, resulting in poor instrumental error characteristics. was.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

FIG. 1 shows a schematic vertical sectional view of an embodiment of the turbine meter of the present invention. In FIG. 1, a turbine meter 1 includes a meter body 3 disposed within a tube 2 consisting of a pair of tubular portions 2a and 2b that can be connected and separated from each other, and an impeller 4 supported on the meter body 3.
is rotated by a fluid to be measured, such as city gas, and the flow rate (flow velocity) of the fluid to be measured is measured from the rotational speed of the impeller 4.

The meter body 3 has an outer shell including an upstream cone member 5 held in the tubular portion 2a and a downstream cone member 6 held in the tubular portion 2b. A bearing holding housing 7 is fixed to the front opening of the downstream cone member 6. The housing 7 has a pair of bearings 9 that support both ends of the shaft 8 of the impeller 4.
, 10, and a pair of bearings 12, 13 for supporting the rotation transmission shaft 11 are also provided.

A worm wheel (not shown) is attached to the rotation transmission shaft 11, and a worm 8a attached to the shaft 8 meshes with this worm wheel. A cover plate 14 is attached to the front surface of the housing 7, and the shaft 8 passes through this cover plate 14 and extends to the outside thereof. The impeller 4 is constructed by attaching a plurality of blades 4b to the outer periphery of a body portion 4a, each twisted at a predetermined angle with respect to the flow.

Since the impeller 4 rotates between the upstream cone member 5 and the downstream cone member 6, gaps 15 and 16 are formed between the outer peripheral edge of the body 4a and the cone members 5 and 6, respectively. It has been done. The vane 4b is located in a flow path 17 defined between the outer wall of the meter body 3 and the inner wall of the tube 2. Reference numeral 18 denotes an introduction pipe that is inserted through the downstream cone member 6 and introduces the fluid that remains on the downstream side of the downstream cone member 6 to the back surface of the body portion 4a of the impeller 4.

A filter 18a made of a mesh having an appropriate coarseness is provided at the opening on the introduction side of the introduction pipe 18 to prevent dust from entering into the introduction pipe 18. Reference numerals 19 and 20 are stirring blades constituting the main part of the present invention, and in this embodiment, the body 4 of the impeller 4
A plurality of sheets are attached to both sides of a by twisting them at a fixed angle.

Both stirring blades 19 and 20 are located within the meter body 3, and therefore, when the impeller 4 rotates, a swirling flow is generated within the meter body 3. Here, the fluid flowing into the pipe 2 from the upstream side collides with the front surface of the upstream cone member 5, flows along its outer wall, and collides with the blades 4b in the flow path 17.

As a result, the impeller 4 is rotated by the fluid colliding with the blades 4b, and the rotation is transmitted to the shaft 8, the worm wheel of the worm 8a1, and the shaft 11 in this order, and is connected to the shaft 11 via the coupling 11a. Meter 1 by output shaft 21
taken outside. The rotation of the output shaft 21 is transmitted to a flow rate indicator (not shown) via a suitable reduction gear mechanism or the like, and is instructed there as the flow rate of the fluid to be measured. The fluid that has passed through the blades 4b of the impeller 4 flows downstream along the peripheral surface of the downstream cone member 6, and gradually recovers its static pressure.

Therefore, the static pressure of the fluid near the opening of the introduction pipe 18 is high, and the fluid near the opening flows into the introduction pipe 18 due to the pressure difference with the inside of the meter body 3. Further, as the impeller 4 rotates, the stirring blades 19 and 20 rotate within the meter body 3, so a swirling flow around the axis is generated around the body portion 4a.

This swirling flow has a relatively high speed near the outer periphery where the stirring blade 20 is located in the space 22 between the downstream cone member 6 and the body 4a, and a relatively low speed near the inner periphery. The pressure is greater near the outer periphery than near the inner periphery. Since this dynamic pressure near the outer periphery is higher than the fluid to be measured flowing through the flow path 17 for a while after the impeller starts rotating four times, a part of the swirling flow flows out from the gap 16 to the flow path 17 . Therefore, during this period, the fluid to be measured in the flow path 17 flows from the gap 16 to the space 22.
cannot be invaded. Furthermore, when a certain period of time has elapsed after the start of four rotations of the impeller, fluid is lost in the space 22 due to the outflow of a portion of the swirling flow, assuming that the introduction of downstream fluid from the introduction pipe 18, which will be described later, is not taken into account. , the pressure as a whole becomes lower than the initial state while maintaining a pressure gradient in which the dynamic pressure near the outer circumference is larger than the dynamic pressure near the inner circumference. Therefore, the dynamic pressure near the outer periphery of the swirling flow is also relatively reduced, and the pressure is approximately the same as that of the fluid to be measured in the flow path 17, which is balanced, and a steady state is established in which no fluid enters or exits through the gap 16. Become. Therefore, even in this steady state, the fluid to be measured cannot enter the space through the gap 16. However, in this case, since the fluid on the downstream side is further introduced into the space 22 through the introduction pipe 18, the amount of fluid flowing out from the gap 16 into the flow path 17 is actually replenished even after the above-mentioned certain period of time has elapsed. Thus, the above-mentioned outflow from the space portion 22 is performed regularly. Also, the upstream cone member 5 and the body portion 4a
A swirling flow similar to that in the space 22 is generated by the stirring blade 19 in the space 23 between the two (i.e., when no downstream fluid is introduced from the introduction pipe 18), and the flow is Road 1
The measured fluid of No. 7 does not enter the space 23 from the gap 15.

These facts have been confirmed through experiments, and even today this type of turbine meter still operates according to this theory. In this way, the fluid to be measured in the flow path 17 does not enter into the spaces 22 and 23 due to the swirling flow generated as the impeller 4 rotates, so dust and dirt do not enter the space 22 and 23, unlike in conventional turbine meters. It is possible to reliably prevent problems such as fluid containing a large amount of dirt entering the meter main body 3 through the gaps 15 and 16, and as a result, the bearing 9 becoming clogged with dust or the like.

Furthermore, even if dust should enter the spaces 22 and 23,
Due to the above-mentioned swirling flow, dust is removed from the cone member 6, which is far from the bearing 9,
This also prevents the above-mentioned inconvenience from being scattered toward the inner circumferential side of 5. Further, when the impeller 4 is stationary, dirt in the fluid that has entered the spaces 23 and 22 through the gaps 15 and 16 is removed from the blades 19 and 20 when the impeller 4 rotates.
Therefore, it is possible to reliably prevent the inconvenience that dust and the like are scattered by the swirling flow generated by the dust and adhere to the vicinity of the body 4a of the impeller 4, which adversely affects the instrumental error characteristics. can.

Furthermore, in the case of this embodiment, since the cover plate 14 is provided on the front surface of the housing 7 so that the bearing 10 is not directly exposed to the fluid in the space 22, dust etc. It is possible to better prevent the intrusion of

In the above embodiment, the rotation speed of the impeller 4 is set to the shaft 8,
11, 21, etc., but without using this kind of mechanical rotation transmission mechanism, for example, the second
The rotation of the impeller 4 may be electrically detected, like a turbine meter 31 shown in the figure.

The turbine meter 31 has an electromagnetic pick-up 32 buried in a portion of the wall of the pipe 2 facing the blade 4b, detects electromagnetic changes that occur each time the blade 4b crosses in front of the electromagnetic pickup 32, and generates a pulse-like signal. The configuration is such that the output is obtained. Furthermore, in each of the above embodiments, the fluid to be measured is not limited to city gas, but may be other gases, and may also be liquids such as oil instead of gases.

Furthermore, in each of the above embodiments, the introduction pipe 18 is not necessarily provided.

Further, in each of the embodiments described above, the stirring blades 19 and 20 are provided on the front and back surfaces of the body 4a of the impeller 4, but the stirring blade 19 on the front side may be omitted.

As described above, in the turbine meter of the present invention, a stirring blade that rotates within a cone member is fixed to the body of an impeller, and a flow generated by the rotation of the stirring blade causes a flow between the impeller and the cone member. Since the gap is sealed from the inside of the cone member, the rotation of the impeller causes the stirring blades inside the cone member to rotate integrally with the impeller, and this rotation causes the agitation blades inside the cone member to rotate. The flow becomes a swirling flow, and the pressure is the same or higher than that of the fluid to be measured flowing outside the cone member,
Due to this pressure difference between the inside and outside of the cone member, the fluid to be measured flowing on the outside of the cone member can be effectively prevented from entering the inside of the cone member. may enter the cone member through the gap between the cone member and the impeller body. If the bearing part gets clogged with dirt, etc.
Another advantage is that it is possible to reliably prevent inconveniences such as deterioration of instrumental error characteristics due to dust adhering to the impeller body.

Furthermore, the rotation of the impeller can be detected by mechanically extracting the rotation of its shaft to the outside, in which case, as described above, the rotation transmission system provided in the cone member contains the Since it is possible to reliably prevent dirt from entering, the rotation speed of the impeller can always be accurately measured, and the rotation of the impeller can be electrically measured by electromagnetic changes that occur as the blades pass. It has the advantage that it can be configured to be taken out to the outside and detected by a means, and that the entire device can be configured extremely simply.

[Brief explanation of the drawing]

1 and 2 are schematic vertical sectional views of first and second embodiments of the turbine meter of the present invention, respectively. 1, 31... Turbine meter, 2...
Pipe, 4... Impeller, 5... Upstream cone member, 6... Downstream cone member, 15, 16
...Gap, 19,20...Blade.

Claims (1)

[Scope of Claims] 1. A pair of cone members disposed facing each other on the upper and downstream sides of a pipe, an impeller having blades implanted on its circumferential surface and rotatably supported between the pair of cone members; A turbine consisting of an agitating blade that is fixed to the body of an impeller, rotates together with the impeller, and generates a swirling flow in a space formed between the body of the impeller and a cone member. meter. 2. The turbine meter according to claim 1, wherein the impeller is configured to detect the rotational speed by extracting the rotation of its shaft to the outside by mechanical means. 3. Claim 1, characterized in that the impeller is configured to detect the rotational speed by extracting electromagnetic changes caused by the passage of the impeller to the outside by electrical means. Turbine meter listed.