JP6618348B2 - Water meter, meter case and manufacturing method thereof - Google Patents

Description

  The present invention relates to a water meter that measures the flow rate of tap water based on the rotation amount of an impeller, a meter case thereof, and a method for manufacturing the meter case.

  As this type of meter case, a pair of relay pipes project in a V shape from the outer peripheral surface of a cylindrical case that houses an impeller, and a pair of water pipe connection portions provided at the tip of the pair of relay pipes. Are known to be arranged on a coaxial straight line (for example, see Patent Document 1).

JP-A-7-270201 (FIG. 2)

  By the way, in order to suppress the amount that the cylindrical case of the meter case protrudes to the side with the water meter attached in the middle of the linearly extending water pipe, It is preferable that the central axis (hereinafter referred to as “water pipe reference axis”) is configured to be orthogonal to the central axis of the cylindrical case. However, when manufacturing multiple types of meter cases with different overall lengths, if all of the multiple types of meter cases have a structure in which the water pipe reference axis is orthogonal to the central axis of the cylindrical case, there is a difference between the multiple types of meter cases. Since the V-shaped leg opening angles of the pair of relay pipes are different, there is a problem that the number of jigs necessary for manufacturing the meter case increases and the manufacturing cost increases. For this reason, at present, the manufacturing leg is given priority and the opening angle of a pair of relay pipes is made common in a plurality of types of meter cases. There has been a problem that the amount of deviation from the central axis of the cylindrical case is extremely large compared to other cases.

  The present invention has been made in view of the above circumstances, and in each of a plurality of types of water meters having different overall lengths, it is possible to suppress the amount projecting from the water pipe to the side and also to suppress the manufacturing cost. An object is to provide a water meter, a meter case, and a manufacturing method thereof.

The invention of claim 1 made to achieve the above object is to provide one of a plurality of types of meter cases having different total lengths of water meters for measuring the flow rate of tap water flowing through a water pipe based on the rotation amount of an impeller. And a cylindrical case in which the impeller is rotatably accommodated, and a V-shape symmetrical to the left and right when viewed from the axial direction of the central axis of the cylindrical case. A pair of relay pipes extending along both sides of the pair, and provided at the tip of the pair of relay pipes, extending in a direction perpendicular to the central axis of the cylindrical case and passing through or near the central axis of the cylindrical case A meter case having a pipe having a common central axis as a water pipe reference line and having a pair of water pipe connection portions respectively connected to the water pipe, the meter case being included in the plurality of types The distance between two intersections between the center axis of the pair of relay pipes and the water pipe reference line in one of the relatively short meter cases is 2S, and the other meter case is relatively long. 2L, the distance between two intersections between the central axis of the pair of relay pipes and the water pipe reference line, and the central axis of the cylindrical case and the central axis of the relay pipe in the one and the other meter cases Is the distance r, and the crossing angle between the central axis of the relay pipe and the water pipe reference line is θ, the crossing angle θ of the one meter case and the distance r and the crossing angle of the other meter case This is a meter case in which θ and the distance r are the same and the relational expression 2r = (S + L) · sin θ is satisfied.

The invention of claim 2 is a water meter having the meter case according to claim 1 .

Invention of Claim 3 is a manufacturing method which manufactures several types of meter cases from which a full length differs as parts of a water meter which measures the flow of tap water which flows through a water pipe based on the amount of rotation of an impeller, The meter case includes a cylindrical case in which the impeller is rotatably accommodated and a cylindrical case that protrudes from an outer peripheral surface of the cylindrical case, and is provided on both sides of a symmetrical V-shape when viewed from the axial direction of the central axis of the cylindrical case. A pair of relay pipes extending along the water pipe and a water pipe provided at the tip of the pair of relay pipes, extending in a direction perpendicular to the central axis of the cylindrical case and passing through the central axis of the cylindrical case or the vicinity thereof Comprising a pipe having a common reference axis as a central axis, and having a pair of water pipe connections connected to the water pipes, a comparison between two types of meter cases included in the plurality of types Short first The distance between two intersections between the central axis of the pair of relay pipes in the meter case and the water pipe reference line is 2S, and the central axis of the pair of relay pipes and the water pipe in the relatively long second meter case The distance between two intersections with the pipe reference line is 2L, the distance between the central axis of the cylindrical case and the central axis of the relay pipe in the first and second meter cases is r, and the central axis of the relay pipe When the crossing angle with the water pipe reference line is θ, the crossing angle θ and the distance r of the first meter case are the same as the crossing angle θ and the distance r of the second meter case, and This is a meter case manufacturing method for manufacturing a meter case so as to satisfy the relational expression 2r = (S + L) · sin θ.

According to a fourth aspect of the present invention, the distance r and the crossing angle θ of the third meter case having an intermediate length between the first and second meter cases are set as the distance between the first and second meter cases. The meter case manufacturing method according to claim 3 , wherein the meter case is manufactured with the same value as r and the crossing angle θ.

According to the meter case and the manufacturing method thereof according to the present invention (the inventions of claims 1 and 3 ), the opening angle of the pair of relay pipes in the two (first and second) meter cases having different lengths is determined. While keeping the same (with the same crossing angle θ), both the water pipe reference lines of the two meter cases are sandwiched between the central axes of the cylindrical cases and at the same distance on both sides from the central axis. Be placed. Thereby, it is prevented that the water pipe reference line of any one of the two meter cases having different lengths is arranged far from the central axis of the cylindrical case. That is, according to the present invention, it is possible to suppress the amount projecting sideways from the water pipe and the manufacturing cost in each of the plurality of types of meter cases.

Further, the distance r and the crossing angle θ of the third meter case whose total length is an intermediate length between the first and second meter cases are the same as the distance r and the crossing angle θ of the first and second meter cases. If the meter case is manufactured in accordance with the value (invention of claim 4 ), the distance between the water pipe reference line of the third meter case and the central axis of the cylindrical case is the water supply of the first and second meter cases. The distance between the tube reference line and the central axis of the cylindrical case can be made smaller. Thereby, in each of three or more types of meter cases, it is possible to suppress the amount projecting laterally from the water pipe and to reduce the manufacturing cost.

Further, when a widely used water meter is manufactured by the above manufacturing method, the crossing angle between the central axis of the relay pipe and the water pipe reference line is 9 to 11.1 degrees. In other words, if the intersection angle between the central axis of the relay pipe and the water pipe reference line is 9 to 11.1 degrees (invention of claim 2 ), when a plurality of types of meter cases having different overall lengths are manufactured, Among these types of meter cases, it is possible not to include those that protrude from the water pipe to the side.

Side sectional view of a water meter according to an embodiment of the present invention. Plan view of meter case (A) Plan sectional view of the first meter case, (B) Plan sectional view of the third meter case, (C) Plan sectional view of the second meter case. (A) Schematic diagram of second meter case, (B) Schematic diagram of first meter case Graph showing the relationship between intersection angle and offset distance

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the water meter 10 of this embodiment includes an impeller 20 inside a cylindrical case 12. The impeller 20 has a structure in which a plurality of blades 22 project radially from the lower end of a cylindrical shaft 21 extending vertically. The cylindrical shaft 21 is closed at the upper end, and is opened at the lower end. The needle 12N rising from the bottom of the cylindrical case 12 enters the cylindrical shaft 21 to enter the ceiling surface in the cylindrical shaft 21. Has been hit.

  A measuring unit 23 is fitted to the cylindrical case 12 above the impeller 20. The measurement unit 23 accommodates a plurality of components inside a cylindrical unit case 24 and is sealed in a watertight state. A flange 24F projects from the upper side surface of the unit case 24, and a packing 25 is sandwiched between the lower surface of the flange 24F and the upper surface of the cylindrical case 12. Then, a presser sleeve 26 is mounted on the cylindrical case 12 from above the measurement unit 23, and a female screw 26 </ b> M on the inner surface of the presser sleeve 26 is screwed to the screw 12 </ b> M on the upper outer peripheral surface of the cylindrical case 12. The measurement unit 23 is pressed from above by a pressing portion 26F projecting inward from the upper end.

  A center recess 24A is provided at the center of the bottom surface of the unit case 24, and the upper end portion of the cylindrical shaft 21 is received therein. And the input rotation component 27 supported rotatably in the unit case 24 and the upper end part of the cylindrical shaft 21 are connected by the magnet couplings 28A and 28B. As a result, the rotation of the impeller 20 is transmitted to the input rotation component 27 so that each component in the unit case 24 operates, and the flow rate of tap water based on the rotation of the impeller 20 is measured. The upper surface of the unit case 24 is a glass plate 24G, and the measurement result is displayed so as to be visible through the glass plate 24G. The presser sleeve 26 is provided with a top cover 29 that rotates so as to open and close the top opening of the presser sleeve 26.

  As shown in FIG. 2, a pair of relay pipes 13, 13 protrude from the outer peripheral surface of the cylindrical case 12 in a symmetrical V-shape. Further, a pair of water pipe connection portions 14 and 14 are provided at the distal ends of the pair of relay pipes 13 and 13, and the meter case according to the present invention is formed from the cylindrical case 12, the relay pipe 13 and the water pipe connection portion 14. 11 is configured.

  The meter case 11 is, for example, a cast part, and the water pipe connection portions 14 and 14 have a cylindrical shape arranged on a coaxial straight line, and a screw portion 14N is formed on the outer peripheral surface of each water pipe connection portion 14. Then, as shown in FIG. 2, the water meter 10 is arranged between the water pipes 90, 90 extending coaxially, and the nut cap 91 provided at the end of each water pipe 90 is a screw of the water pipe connection portion 14. By being screwed into the section 14N, the water meter 10 is attached to the water pipe 90, and the flow rate of tap water flowing through the water pipe 90 can be measured by the water meter 10.

  By the way, the meter case 11 is provided with a plurality of types having different total lengths C (distances between the end faces of the pair of water pipe connection portions 14 and 14). As an example, the first to third meters are shown in FIG. Case 11 is shown. The first meter case 11 is shown in FIG. 3A. For example, the first meter case 11 is for a water pipe 90 having a diameter of 20 [mm] and has a total length C of 190 [mm]. 3 (C), for example, for a water pipe 90 having a caliber of 25 [mm] and a total length C of 225 [mm]. The third meter case 11 is shown in FIG. 3 (B). For example, the length C is 210 [mm] for a water pipe 90 having a diameter of 25 [mm].

  Here, in all of the first to third meter cases 11, if the water pipe reference line 14J that is the central axis of the water pipe connecting portions 14 and 14 is configured to be orthogonal to the central axis 12J of the cylindrical case 12, The protruding amount B of the cylindrical case 12 from the water pipe reference line 14 </ b> J indicated by the symbol B in FIG. 2, that is, the protruding amount of the cylindrical case 12 to the side of the water pipe 90 is the first to third meter cases 11. Are minimized (that is, the radius of the cylindrical case 12).

  However, if it does so, the open leg angles of the pair of relay pipes 13 and 13 in each of the first to third meter cases 11 will be different. Three types of jigs (not shown) used when processing the screw portions 14N and the end faces of the connection portions 14 and 14 are required. And the setup work of these jigs requires a great deal of labor, and the manufacturing cost increases.

  On the other hand, in this embodiment, after making the opening leg angles of the relay pipes 13 and 13 the same between the first to third meter cases 11, each of the first to third meter cases 11 is provided. In order to keep the amount of overhang of the cylindrical case 12 with respect to the water pipe 90 in FIG.

  That is, regarding the first meter case 11 having the shortest overall length among the first to third meter cases 11, as shown in FIG. 3A, the central axes 13J, 13J of the pair of relay pipes 13, 13 are used. The water pipe reference line 14J is offset from the central axis 12J of the cylindrical case 12 to the intersection P3 side with respect to the intersection P3, and conversely, the second meter case 11 having the longest overall length is shown in FIG. As shown in FIG. 3C, the water pipe reference line 14J is offset from the intersection P3 on the side further away from the central axis 12J of the cylindrical case 12. Then, a distance z between the water pipe reference line 14J and the central axis 12J of the cylindrical case 12 in the first meter case 11 (hereinafter referred to as “offset distance” as appropriate) and an offset distance y of the second meter case 11 Are the same size. Further, the offset distance of the third meter case 11 shown in FIG. 3B is smaller than the offset distances y and z of the first and second meter cases 11.

  Hereinafter, in order to explain in detail, as shown in FIG. 2, two intersections P1, P1 of the central axes 13J, 13J of the pair of relay pipes 13, 13 and the water pipe reference line 14J in the second meter case 11 Similarly, the distance between them is 2L, and similarly, the distance between the two intersections P1 and P1 in the relatively short first meter case 11 is 2S. Further, in common with both the first and second meter cases 11, the distance between the central axis 12J of the cylindrical case 12 and the central axis 13J of the relay pipe 13 is r, the central axis 13J of the relay pipe 13 and the water pipe standard Let the crossing angle with the line 14J be θ. Furthermore, for the purpose of explaining the relational expression described later, the first reference line parallel to the water pipe reference line 14J and passing through the central axis 12J of the cylindrical case 12 is K1, the central axis 13J of the relay pipe 13 and the first reference line The distance from the intersection P2 with the line K1 to the center P4 of the cylindrical case 12 is m, and the distance in the direction parallel to the first reference line K1 between the intersections P1 and P2 is n.

  Then, as shown in the schematic diagram of the second meter case 11 shown in FIG. 4 (A), the water pipe reference line 14J is at the intersection P3 between the central axes 13J and 13J of the pair of relay pipes 13 and 13. When the cylindrical case 12 is located on the side away from the central axis 12J by an offset distance y, as shown by triangles P1, P2, P6 and triangles P2, P4, P5 in FIG. Relational expressions (1) and (2) hold.

r = m · sin θ (1)
y = n · tan θ (2)

  Further, the following relational expression (3) is obtained by eliminating m and n from the relation of L = m + n and the relational expressions (1) and (2), and the relational expression (3) is arranged to be a relational expression. (4) is obtained.

L = r / sin θ + y / tan θ (3)
y = (L · sin θ−r) / cos θ (4)

  On the other hand, as in the first meter case 11 shown in FIG. 4B, the water pipe reference line 14J is connected to the cylindrical case 12 with respect to the intersection P3 between the central axes 13J and 13J of the pair of relay pipes 13 and 13. Is located at the intersection P3 side from the central axis 12J by an offset distance z, as shown by triangles P1, P2, P6 and triangles P2, P4, P5 in the figure, the following relational expression ( 5) and (6) hold.

r = m · sin θ (5)
z = n · tan θ (6)

  Further, the following relational expression (7) is obtained by eliminating m and n from the relation S = mn, and the relational expressions (5) and (6), and the relational expression (7) is arranged. Relational expression (8) is obtained.

S = r / sin θ−z / tan θ (7)
z = (r−S · sin θ) / cos θ (8)

  Since the offset distance z and the offset distance y are the same between the first and second meter cases 11, that is, y = z, the following relational expression (9) is established.

      2r = (S + L) · sin θ (9)

  As described above, in the meter case 11 of the present embodiment, the two meter cases 11, 11 of the shortest meter case 11 and the longest meter case 11 among a plurality of types (first to third) meter cases 11 having different overall lengths. While the leg angle of the pair of relay pipes 13 and 13 is the same (the crossing angle θ is the same in the range of 9 to 11.1 degrees), both water pipe reference lines of the two meter cases 11 and 11 are used. 14J and 14J are arranged at positions spaced apart from the central axis 12J by the same offset distance with the central axis 12J of the cylindrical case 12 therebetween. As a result, the offset distance of one of the two longest and shortest meter cases 11, 11 among a plurality of types of meter cases 11 having different overall lengths can be prevented from becoming biased. That is, according to the present embodiment, the amount of overhanging from the water pipe 90 to the side can be suppressed and the manufacturing cost can be suppressed in each of the plural types of meter cases 11. Further, the distance r and the crossing angle θ of the meter case 11 (third meter case 11) having an intermediate length excluding the longest and the shortest among a plurality of types of meter cases 11 having different total lengths are set to the shortest and longest meter cases 11. , 11 and the same value as the crossing angle θ, the offset distance of the intermediate length meter case 11 can be made smaller than the offset distance of the shortest and longest meter cases 11, 11. Thereby, in the whole of a plurality of types of meter cases 11, it is possible to suppress the amount projecting laterally from the water pipe 90 and to reduce the manufacturing cost.

  The first to third meter cases 11 described above can be manufactured as follows. First, the distance r is determined. The distance r greatly affects the instrumental performance. Therefore, a plurality of meter cases 11 having different distances r are prepared and each water meter 10 is assembled, and an experiment for measuring an error between the actual flow rate of the water meter 10 and the actually measured flow rate, that is, an instrumental difference, is performed. And the value of the distance r within which the instrumental difference falls within the allowable range may be determined based on the experimental result.

  Next, under the distance r determined as described above, for example, when the crossing angle θ of the first and second meter cases 11 and 11 is changed to a plurality of values, The offset distances y and z described above are obtained by drawing using, for example, CAD. Then, as shown in FIG. 5, graphs g1 and g2 are created with the crossing angle θ as the horizontal axis and the offset distances y and z as the vertical axis. Here, in the vertical axes of the graphs g1 and g2 in FIG. 5, when the water pipe reference line 14J is located on the intersection P3 (see FIG. 2) side with respect to the central axis 12J of the cylindrical case 12, it is plus. Is shown as negative. Then, the crossing angle θ (10.1 degrees in the graph of FIG. 5) when the horizontal axis g3 meaning the offset distance “0” crosses the center in the vertical direction of the graphs g1 and g2 is the first to the first. The common intersection angle θ in the three meter cases 11 is determined.

  Then, by manufacturing a plurality of types of meter cases 11 that are unified to the intersection angle θ and the distance r determined as described above, a jig can be used in common among the plurality of types of meter cases 11. Costs can be reduced.

  In addition, if the crossing angle θ is the same in the range of 9 to 11.1 degrees between the first to third meter cases 11, the distance between the central axis 12J of the cylindrical case 12 and the water pipe reference line 14J is set. 3.3 [mm] or less, the amount of the cylindrical case 12 projecting laterally from the water pipe 90 is suppressed, and a water meter widely used in all of the first to third meter cases 10 can be stored in a water meter-box for accommodating 10 units. At this time, by setting the crossing angle θ to 10 degrees between the first to third meter cases 11, the offset distance z in the first meter case 11 is +1.5 [mm], and the second meter case The distance offset distance y at 11 is −1.5 [mm], and both the water pipe reference lines 14J and 14J of the two meter cases 11 sandwich the central axis 12J of the cylindrical case 12 from the central axis. They can be placed on both sides at the same distance.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following are within the scope not departing from the gist. It can be changed and implemented.

(1) In the above-described embodiment, an example in which all of a plurality of types of meter cases 11 having different total lengths are set to the same distance r and crossing angle θ has been described. The case 11 may have the same distance r and the crossing angle θ, or may have a meter case 11 that has a distance r and a crossing angle θ that are different from the other meter cases 11 as an exception.

(2) Separately from the above embodiment, as a method of determining the crossing angle θ, the intersection points P1 and P1 in the water pipe reference axis 14J orthogonal to the central axis 12J of the cylindrical case 12 from the total length C of the first meter case 11 And the distance 2L between the intersections P1 and P1 in the water pipe reference axis 14J perpendicular to the central axis 12J of the cylindrical case 12 is estimated from the total length C of the second meter case 11. Then, the intersection angle θ is calculated based on the values of the distance 2S and the distance 2L, the distance r determined in the above-described experiment, and the relational expression (9), which are calculated as the first to third meter cases. 11 may be a common intersection angle θ.

DESCRIPTION OF SYMBOLS 10 Water meter 11 Meter case 12 Cylindrical case 13 Relay pipe 13J Central axis 14 Water pipe connection part 14J Water pipe reference line 20 Impeller 90 Water pipe

Claims (4)

A meter case that forms one of a plurality of types of meter cases with different total lengths of water meters that measure the flow rate of tap water flowing through the water pipe based on the rotation amount of the impeller,
A cylindrical case in which the impeller is rotatably housed;
A pair of relay pipes projecting from the outer peripheral surface of the cylindrical case and extending along both sides of a symmetrical V-shape when viewed from the axial direction of the central axis of the cylindrical case;
Tubular pipe provided at the tip of the pair of relay pipes, extending in a direction orthogonal to the central axis of the cylindrical case and passing through the central axis of the cylindrical case or the vicinity thereof and having a common central axis as a water pipe reference line In a meter case provided with a pair of water pipe connection portions respectively connected to the water pipes,
Between the meter case and another meter case included in the plurality of types, the distance between two intersections of the central axis of the pair of relay pipes and the water pipe reference line in one of the relatively short meter cases 2S, the distance between two intersections of the central axis of the pair of relay pipes and the water pipe reference line in another relatively long meter case is 2L, and the cylindrical case in both the one and the other meter cases When the distance between the central axis and the central axis of the relay pipe is r, and the intersection angle between the central axis of the relay pipe and the water pipe reference line is θ,
The crossing angle θ and the distance r of the one meter case are the same as the crossing angle θ and the distance r of the other meter case, and
2r = (S + L) · sin θ
A meter case that satisfies the relational expression of A water meter having the meter case according to claim 1. As a part of a water meter that measures the flow rate of tap water flowing through a water pipe based on the rotation amount of an impeller, a manufacturing method for manufacturing a plurality of types of meter cases having different overall lengths,
The meter case is
A cylindrical case in which the impeller is rotatably housed;
A pair of relay pipes projecting from the outer peripheral surface of the cylindrical case and extending along both sides of a symmetrical V-shape when viewed from the axial direction of the central axis of the cylindrical case;
Tubular pipe provided at the tip of the pair of relay pipes, extending in a direction orthogonal to the central axis of the cylindrical case and passing through the central axis of the cylindrical case or the vicinity thereof and having a common central axis as a water pipe reference line Comprising a pair of water pipe connections connected to the water pipes,
The distance between two intersections between the central axis of the pair of relay pipes and the water pipe reference line in the relatively short first meter case among the two types of meter cases included in the plurality of types is relatively 2S. The distance between two intersections between the central axis of the pair of relay pipes in the long second meter case and the water pipe reference line is 2L, and the central axis of the cylindrical case in the first and second meter cases When the distance from the central axis of the relay pipe is r, and the intersection angle between the central axis of the relay pipe and the water pipe reference line is θ,
The crossing angle θ and the distance r of the first meter case are the same as the crossing angle θ and the distance r of the second meter case, and
2r = (S + L) · sin θ
The meter case manufacturing method for manufacturing the meter case so as to satisfy the relational expression. The distance r and the crossing angle θ of the third meter case having an intermediate length between the first and second meter cases are set as the distance r and the crossing angle θ of the first and second meter cases. The method for manufacturing a meter case according to claim 3, wherein the meter case is manufactured with the same value.

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