JP4900912B2 - Single box tangential flow impeller weighing device - Google Patents

Description

  The present invention is a single box type tangential flow for measuring the flow rate of the fluid to be measured by applying the jet of the fluid to be measured flowing into the impeller chamber from the inflow side nozzle to the blade of the impeller and pushing the impeller to rotate. The present invention relates to an impeller-type weighing device.

  In this specification, a tangential flow impeller-type water meter which is an embodiment of a tangential flow impeller-type metering device will be described. A tangential flow impeller-type water meter rotates the impeller by jetting and rotating a fluid to be measured (in this example, water) at a right angle to the impeller, and mechanically converts the flow rate. It is used most often because it is simple in structure, has few failures, and is inexpensive. The one in which the measuring chamber (impeller chamber) of the impeller also serves as an outer box is referred to as a “single box type”, and the one in which the measuring chamber and the outer box are provided separately is referred to as a “double box type”. Yes.

  In the case of a water meter having a conventional configuration, there is a basin called “peak” in the instrumental error characteristic. Normally, the instrumental error is positive in this basin compared to other areas. In order to improve this problem, for example, a water meter is disclosed that suppresses the peak basin by a slide type adjustment mechanism and has a flat instrumental difference characteristic (see Patent Document 1).

Here, the inflow side nozzle and the outflow side nozzle are integrally formed in the outer case of the single box water meter. Since the outer case needs to have a pressure-resistant structure, each nozzle is usually formed by cutting a copper alloy. In addition, the water meter may reuse the outer case, and there is a product called “repair meter” that combines an outer case of one manufacturer and a lower case of another manufacturer. However, each nozzle can affect the number of rotations correlated with the flow rate by their position, angle and diameter. For this reason, in the case of the above-described repair meter, it may be difficult to adjust the instrumental error only with the conventional adjustment mechanism due to processing accuracy and errors between manufacturers.
JP 2004-53471 A

  In view of the above-mentioned problems, the present invention has an object to enable adjustment of instrumental error even in a single box type tangential flow impeller type weighing device, even if the outer case and the lower case are of different manufacturers. Yes.

Means for Solving the Problems and Effects of the Invention

In the invention of claim 1 for solving the above-described problem, the impeller chamber of the case is provided with an adjustment mechanism for suppressing the flow of the fluid to be measured flowing from the inflow side nozzle, and the impeller chamber is provided. In a single box type tangential flow impeller-type metering device in which a fluid to be measured is introduced as a jet flow from an inflow-side nozzle, the jet flow is applied to the impeller blades, and the impeller is pushed around, and then flows out from the outflow-side nozzle. A rectifying member for rectifying the jet of the fluid to be measured is attached between the inflow side nozzle and the adjustment mechanism in the flow path of the fluid to be measured, and the rectifying member is in a direction orthogonal to the jet direction of the fluid to be measured. The pair of rectifying plates are opposed to each other at a predetermined interval, and the pair of rectifying plates are each independently centered on the axis of each support shaft provided along the axial direction of the impeller. rotatably mounted to It is characterized by a door.

  The fluid to be measured flowing into the impeller chamber from the inflow side nozzle becomes a jet and collides with the impeller while slightly diffusing. A part of the jet changes its direction and becomes turbulent in the upper space having the largest gap, which affects the rotation of the impeller. Here, since most of the characteristics of the jet of the fluid to be measured are determined by the inflow side nozzle, the influence of the variation in the shape of the inflow side nozzle on the instrumental error of the apparatus is large. In the single box tangential flow impeller measuring device according to the present invention, in addition to adjusting the characteristics of the fluid to be measured by the adjusting mechanism, the jet of the fluid to be measured entering the upper space is rectified to the rectifying member. Therefore, the characteristics are adjusted, so that good jet characteristics with reduced variation can be obtained. As a result, the instrumental error can be easily adjusted.

  By using a pair of rectifying members as the rectifying member, a large rectifying effect can be obtained despite the simple configuration.

  By rotating each baffle plate, the jet direction of the fluid to be measured can be slightly changed. For this reason, while being able to extend a rectification | straightening range, the jet which has various characteristics can be created by rotating each rectification | straightening board independently.

According to a second aspect of the present invention, on the premise of the first aspect of the invention, the pair of rectifying plates have an end surface portion from the side facing the inflow side nozzle to the side facing the impeller in the jet direction of the fluid to be measured. On the other hand, it is characterized by an arc shape or an inclined surface shape.

  When the fluid to be measured is rectified, the fluid to be measured hits the end surface portions of the pair of rectifying plates, and turbulent flow is likely to occur, but the end surface portion has an arc shape or an inclined surface shape with respect to the jet direction of the fluid to be measured. Therefore, the collision with the fluid to be measured is alleviated and the generation of turbulence is suppressed. This facilitates adjustment of the instrumental error.

According to a third aspect of the invention, on the premise of the first or second aspect of the invention, the thickness of the pair of rectifying plates gradually decreases as the end face portion is approached.

According to the invention of claim 3 , the collision with the fluid to be measured is further alleviated, and the generation of turbulent flow is further suppressed. This makes it easier to adjust the instrumental error.

Rectifying member described above is, in some cases that will be molded integrally with the unit main body portion of the single-box type tangential flow impeller metering device.

In such a case, there is an effect that the manufacture of the rectifying member is simplified.

  Examples of the present invention will be described. 1 is a front cross-sectional view of a water meter M according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a perspective view from below of a pair of rectifying plates 9.

  First, the configuration of the water meter M will be described. As shown in FIG. 1, the water meter M includes a lower case 1, a register box 2 fitted and attached to the lower case 1, and a fitted and attached to the lower case 1 so as to cover the register box 2. The upper case 3 is formed. The lower case 1 is provided with an inflow side nozzle 4 and an outflow side nozzle 5. In addition, the measuring chamber (impeller chamber 6) is formed in a state where the register box 2 is fitted and attached to the lower case 1. In the lower half of the impeller chamber 6, a blade accommodating space 8 for accommodating the blade 7 a of the impeller 7 rotatably supported by the register box 2 is formed. In the upper half (the upper portion of the blade accommodating space 8), an upper space 11 for arranging an adjusting mechanism (movable resistance plate 16 described later) and a pair of rectifying plates 9 according to the present invention is formed.

  The fluid to be weighed (in the case of this embodiment, water) flowing in from the inflow side nozzle 4 enters the impeller chamber 6 via the strainer 12 and collides with the blade 7a of the impeller 7 as a jet, The impeller 7 is rotated. Thereafter, the water flows out from the outflow side nozzle 5 to the outside. The rotation of the impeller 7 at this time is transmitted to the instruction unit 13 through a magnet (not shown) attached to the tip end of the impeller shaft 7b, and the passage flow rate of water is integrated and displayed on the display unit 14. In addition, each arrow in FIG. 1 has shown the jet direction 15 of water.

  The adjustment mechanism will be briefly described. As shown in FIGS. 1 and 2, the adjustment mechanism of the present embodiment includes a movable resistance plate 16 that is curved in an arc shape, and a support that is provided so as to hang from the inner peripheral surface (lower surface) of the movable resistance plate 16. And a protrusion 18 projecting from the outer peripheral surface (upper surface) of the movable resistor plate 16. An insertion hole 17a is provided in the support portion 17 along the width direction of the movable resistance plate 16, and a sealing screw 19 is inserted through the insertion hole 17a. The insertion hole 17 a is a long hole substantially along the circumferential direction of the movable resistance plate 16.

  A fixed resistance plate 21 is fixed to the bottom surface of the register box 2 adjacent to the movable resistance plate 16. The sealing screw 19 described above is screwed into a female screw (not shown) of the support portion 21a of the fixed resistance plate 21. For this reason, the movable resistance plate 16 can be rotated around the axis of the sealing screw 19 and the size (area) of the portion where the movable resistance plate 16 protrudes below the register box 2 is adjusted. Can do. The movable resistance plate 16 can be fixed at a predetermined position by tightening the sealing screw 19.

  The movable resistance plate 16 and the fixed resistance plate 21 described above are disposed substantially orthogonal to the water jet direction 15 in order to suppress the flow of water. Then, the instrumental error is adjusted by rotating the movable resistive plate 16 and adjusting the area of the movable resistive plate 16 that collides with water.

  Next, the pair of rectifying plates 9 according to the present invention will be described. As shown in FIGS. 2 to 4, a rectifying member is attached between the inflow side nozzle 4 and the movable resistance plate 16 in the flow path of the water at the bottom of the register box 2. The rectifying member of the present embodiment is a pair of rectifying plates 9, which are arranged to face each other at a predetermined interval in a direction orthogonal to the water jet direction 15 immediately before the inflow side nozzle 4 side of the movable resistance plate 16. Yes. Each rectifying plate 9 is substantially L-shaped in a side view (as viewed from the inflow side nozzle 4 side), and an upper bent portion 9 a is brought into contact with the bottom surface portion of the register box 2 and fixed by a mounting screw 22. The As a result, each mounting screw 22 is disposed along the axial direction of the impeller shaft 7 b of the impeller 7. By loosening each mounting screw 22, each rectifying plate 9 can be independently rotated around the axis of the corresponding mounting screw 22. In FIG. 4, the rotation direction 23 of each baffle plate 9 is shown by an arrow.

  By rotating the respective rectifying plates 9 and adjusting their arrangement, the size of the openings 24 of the pair of rectifying plates 9 (the flow rate of water colliding with the movable resistance plate 16) is adjusted. That is, by rotating the current plates 9 inward and bringing their front portions (sides facing the inflow side nozzles 4) closer to each other, the opening 24 becomes narrower and the amount of water inflow is reduced. By separating, the opening 24 becomes wide and the amount of water inflow increases. As a result, the difference between the nozzles 4 on the inflow side and the outflow side that could not be dealt with only by adjusting the movable resistance plate 16 (adjustment of the area of the movable resistance plate 16 protruding from the bottom surface of the register box 2). 5), the instrumental error caused by the machining accuracy and the error between manufacturers can be adjusted.

  And as FIG. 3 shows, in each baffle plate 9 of a present Example, the end surface part 9b (surface on the side which collides with the jet of water) from each front becomes downward circular arc shape. Yes. For this reason, the collision between the end face portion 9b of each rectifying plate 9 and the jet of water is alleviated, and the occurrence of turbulence is suppressed. This facilitates adjustment of the instrumental error.

  Furthermore, as shown in FIG. 4, the end surface portion 9 b of each rectifying plate 9 has an acute angle in a cross-sectional view in the radial direction. That is, the thickness of each rectifying plate 9 is gradually reduced as the end face portion 9b is approached (becomes thinner). For this reason, the collision between the end face portion 9b of each rectifying plate 9 and the water jet is further alleviated, and the occurrence of turbulence is further suppressed. This makes it easier to adjust the instrumental error.

  The operation of the water meter M of this embodiment will be described. A pair of rectifying plates 9 are attached at a predetermined interval in a direction orthogonal to the water jet direction 15 immediately before the movable resistance plate 16 on the bottom surface of the register box 2. Each rectifying plate 9 can rotate independently about the axis of the mounting screw 22. The instrumental error of the water meter M can be adjusted by rotating the movable resistor plate 16 and adjusting the area of the portion where the movable resistor plate 16 and the water jet collide. Further, by rotating the respective rectifying plates 9 and adjusting the size of the opening 24 formed by the front portions thereof, the instrumental error (inflow side and It is also possible to adjust the processing accuracy of the nozzles 4 and 5 on the outflow side and the instrumental error caused by errors between manufacturers. This means that the instrumental error can be adjusted even when the water meter M is a repair meter. And while the end surface part 9b of each baffle plate 9 becomes circular arc shape, those thickness is reducing gradually. Thereby, since generation | occurrence | production of a turbulent flow can also be suppressed, adjustment of an instrument difference becomes still easier.

  The end face portion 9b of each rectifying plate 9 has an arc shape with respect to the water jet direction 15, but may be inclined with respect to the water jet direction 15 as shown in FIG. . Even in this case, the same effects as in the case of the first embodiment are obtained.

  The present applicant measured the instrumental difference with respect to the flow rate after adjusting the size of the opening 24 of the pair of rectifying plates 9 in the four types of water meters M. The results are shown in the graph. Like the two curves 25 indicated by solid lines in the middle of FIG. 6, a curve with an overall inclination (for example, a curve 26 indicated by a broken line at the top of FIG. 6) or a recess ( A curve in which drooping occurs (for example, a curve 27 displayed by a broken line at the bottom of FIG. 6) is flat throughout, and the value of the instrumental difference in the peak region of the flow rate-equalizer difference curve is It was confirmed that it became smaller.

It is front sectional drawing of the water meter M of the Example of this invention. It is the sectional view on the AA line of FIG. FIG. 4 is a perspective view from below of a pair of rectifying plates 9. FIG. 10 is an explanatory diagram of the operation of a pair of rectifying plates 9 It is a perspective view from the downward direction of the baffle plate 9 of another Example. It is the graph which measured the instrumental difference with respect to flow volume.

Explanation of symbols

M: Water meter (single box type tangential flow impeller type measuring device)
1: Lower case (case)
2: Register box (device main unit)
4: Inlet nozzle
5: Outlet nozzle
6: Impeller room
7: Impeller
7a: Feather
7b: Impeller shaft (impeller shaft)
9: Current plate
9b: End face part
15: Jet direction
16: Movable resistance plate (adjustment mechanism)
22: Mounting screw (support shaft)

Claims (3)

An adjustment mechanism for suppressing the flow of the fluid to be measured flowing from the inflow side nozzle is provided in the impeller chamber of the case, and the fluid to be measured flows into the impeller chamber from the inflow side nozzle as a jet flow. In a single box type tangential flow impeller-type metering device that blows the impeller against the impeller blades and pushes the impeller around, then flows out from the outflow side nozzle.
A rectifying member for rectifying the jet of the fluid to be measured is attached between the inflow side nozzle and the adjusting mechanism in the flow path of the fluid to be measured ,
The rectifying member is composed of a pair of rectifying plates arranged to face each other at a predetermined interval in a direction perpendicular to the jet direction of the fluid to be measured,
The pair of rectifying plates are attached to each other so as to be independently rotatable about the axis of each support shaft provided along the axial direction of the impeller . Flow impeller type weighing device. The pair of rectifying plates are characterized in that end surfaces from the side facing the inflow side nozzle to the side facing the impeller have an arc shape or an inclined surface shape with respect to the jet direction of the fluid to be measured. The single box type tangential flow impeller type metering device according to claim 1 . The single box type tangential flow impeller-type metering device according to claim 1 or 2 , wherein the thickness of the pair of rectifying plates gradually decreases as approaching the end face portion.

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