JP2019060636A - Positive displacement flow detector - Google Patents

Abstract

To reduce pressure loss of a piston type positive displacement flow detector.SOLUTION: A fluid flows into a cylinder interior space 3011 of metering units adjacent to a top dead center of a piston 302 from an opening on a bottom dead center side of the piston 302, and flows through a communication hole 3012 into a space on a top dead center side from the piston 302 of the cylinder interior space 3011 of the metering units provided adjacently in a counterclockwise direction. When the piston 302 moves from the bottom dead center to the top dead center, the fluid flowing into the space on the top dead center side from the piston 302 is discharged by the piston 302 from an outflow hole 3013 through the opening of the top dead side of the cylinder interior space 3011 and a space between the communication hole 3012 of the metering units provided adjacently in a clockwise direction and a central constriction of the piston 302. A flow rate is calculated from a rotation amount of a crankshaft 303 which rotates in conjunction with reciprocating motion of the piston 302.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a positive displacement flow detector.

As a positive displacement flow rate detector, a piston positive displacement flow rate detector shown in FIG. 10 is known (for example, Patent Document 1).
The positive displacement flow rate detector 10 shown in FIG. 10 includes four cylinders 11_1-11_4 which are directed in different directions by 90 °, and four pistons 12_1-12_4 which reciprocate in the cylinders 11_1-11_4. There is. These four pistons 12_1 to 12_4 perform reciprocating operations in which the phases are sequentially shifted by 90 ° in each of the cylinders 11_1 to 11_4, as shown in FIGS. 10a to 10d.

  A crankshaft 13 is provided at the center of the four cylinders 11_1-11_4, and each piston 12_1-12_4 is connected to a position of the crankshaft 13 eccentrically from the rotation axis by each connecting rod 14_1-14_4. There is. The movement of the pistons 12_1-12_4 is transmitted to the crankshaft 13 via the connecting rods 14_1-14_4, and the crankshaft 13 rotates in the arrow X direction by the movement of the pistons 12_1-12_4.

  The fluid that has flowed into the positive displacement flow rate detector flows into the space on the crankshaft 13 side of each of the cylinders 11_1-11_4. The ports P1-P4 of the flow paths 15_1-15_4 are connected to positions of the cylinders 11_1-11_4 on the outer peripheral side of the positive displacement flow rate detector 10. Further, the flow paths 15_1-15_4 are connected to the position on the inner peripheral side of the positive displacement flow rate detector 10 of the adjacent cylinders 11_1-11_4, and the flow paths 15_1-15_4 of the adjacent cylinders 11_1-11_4. At a position adjacent to the outlet of the port, there are provided ports E1 to E4 connected to the outlet of the volumetric flow detector.

  The fluid having flowed into the positive displacement flow rate detector flows into the space on the lower dead center side (inner peripheral side) of the piston 12 of the first cylinder 11 where the piston 12 is in the vicinity of the upper dead center. The flow path 15 between the first cylinder 11 connected to the inner peripheral side of the first cylinder 11 and the adjacent second cylinder passes the port P of the second cylinder of the flow path 15 It flows into the space on the top dead center side of the piston 12 of the second cylinder 11. Then, when the piston 12 of the second cylinder 11 moves toward the top dead center, the fluid that has flowed into the second cylinder 11 passes through the port P of the second cylinder and then the first cylinder 11. Is pushed back into the flow passage 15 between the cylinder and the second cylinder. At this time, the piston 12 of the first cylinder 11 connects the port E of the first cylinder 11 and the opening on the inner peripheral side of the first cylinder 11 of the flow path 15 between the second cylinder 11. The fluid that has been closed back into the flow path 15 by the piston 12 of the second cylinder 11 is in a position where it is formed by the constriction provided at the central portion of the piston and the first cylinder 11. Through the space, the opening on the inner peripheral side of the first cylinder 11 is pushed out to the port E of the first cylinder 11 and discharged to the outlet.

  As a result, with the movement of each piston 12_1-12_4, it flows in the direction of each arrow (except arrow X) shown in FIG. 10a-d, and a certain amount of fluid flows out to the outlet side per one rotation of the crankshaft 13.

  Therefore, the flow rate passing through the positive displacement flow rate detector can be measured from the amount of rotation of the crankshaft 13.

JP, 2012-181083, A

  According to the above-described positive displacement flow rate detector, as the flow path for transferring the fluid between the adjacent cylinders 11, the port P at the position on the outer peripheral side of the positive displacement flow rate detector 10 of the piston 12 of each cylinder 11; Since the relatively long flow path 15 is used to connect the adjacent cylinder 11 with the port E at the position on the inner peripheral side of the positive displacement flow rate detector 10, the pressure loss of the fluid by the flow path 15 is compared Was huge. The pressure loss due to the positive displacement flow rate detector is preferably as small as possible because the positive displacement flow rate detector itself affects the fluid to be measured and the measurement accuracy.

  Also, in order to connect a plurality of connecting rods to one crankshaft, it is necessary to provide connecting rods in the axial direction of the crankshaft in an overlapping manner, which is a positive displacement flow detector in the axial direction of the crankshaft. It was an obstacle to thinning.

  Also, even if only one set of cylinder and piston is broken because each set of cylinder and piston is integrally connected by the connecting rod around the crankshaft, it is possible to replace the set. It was relatively difficult to repair.

Then, this invention makes it a 1st subject to provide a piston-type positive displacement flow detector which reduced pressure loss.
Another object of the present invention is to provide a piston-type positive displacement flow sensor having a structure suitable for thinning.
The third object of the present invention is to provide a piston-type positive displacement flow sensor having a structure that facilitates replacement and repair.

  In order to achieve the above object, the present invention provides a plurality of positive displacement flow detectors, each having an inlet and an outlet, disposed in an enclosed space, for detecting a flow of fluid flowing from the inlet to the outlet. A weighing block having a weighing unit, a rotation detecting means, and a phase difference regulating means are provided. Each of the measuring units includes a cylinder block provided with a cylinder internal space, a piston having a central narrow portion in the axial direction sliding on the cylinder internal space, and a crankshaft supported by the cylinder block. A connecting rod is provided for connecting the crankshaft and the piston and interlocking the reciprocating motion between the bottom dead center and the top dead center in the cylinder internal space of the piston with the rotational motion of the crankshaft. The cylinder block has an outer surface including a first surface, a second surface, and a third surface, and the cylinder internal space is a bottom dead center which is an opening of the first surface into which the connecting rod is inserted. It is a through hole in which the side opening and the top dead center side opening which is the opening of the second surface are openings at both ends. The cylinder block has a communication hole which is a hole penetrating from the third surface to the cylinder internal space, and a discharge hole which is a hole penetrating from the outer surface to the cylinder internal space. And when the piston of the said measurement unit is located in the vicinity of the bottom dead center, the opening of the said communication hole and the said cylinder internal space side of the said discharge hole is within the range of the said constriction of the said piston about the axial direction of the said piston When the piston of the measuring unit is located near the top dead center, the opening in the axial direction of the piston is larger than the range of the piston in the axial direction of the piston. Provided at a position close to the bottom dead center side opening and at least a part of which is out of the range of the piston in the axial direction of the piston only when the piston is located near the top dead center The opening on the cylinder internal space side of the discharge hole is closer to the top dead center side opening than the opening on the cylinder internal space side of the communication hole, It is provided at positions which are within the skill of the piston for the axial direction of the piston. Further, the plurality of weighing units are cyclically sequentially arranged adjacent to each other so that a loop formed by the plurality of weighing units is formed, and a first direction traveling along the loop is a forward direction; The second surface of the cylinder block of each of the weighing units is the third surface of the cylinder block of the adjacent weighing units in the forward direction, with the direction forward to the first direction along the loop being the reverse direction. And the opening on the third surface side of the communication hole of the cylinder block of each weighing unit is provided at a position overlapping the top dead center side opening of the weighing unit adjacent in the reverse direction, each weighing unit The opening on the outer surface side of the discharge hole of the cylinder block is provided in a portion of the outer surface not in contact with the cylinder block of the other measuring unit. Further, the opening on the outer surface side of the discharge hole of each of the weighing units is in communication with the discharge port, and the bottom dead center side opening of the cylinder block of each of the weighing units is in communication with the inflow port There is. Then, the phase difference regulating means is configured to move the crankshaft of each of the weighing units forward such that the phase of rotation of the crankshaft of each of the weighing units is forward of the phase of rotation of the crankshaft of the weighing unit adjacent in the forward direction. And restricts the phase of rotation of the at least one measuring unit, and the amount of rotation of the crankshaft of at least one of the weighing units is detected.

  According to such a positive displacement flow rate detector, it is possible to shorten the length of the communication hole for transferring the fluid between the cylinder internal spaces, thereby reducing the pressure loss of the fluid by the positive displacement flow rate detector.

  Further, according to such a positive displacement flow rate detector, since the crankshaft is provided for each piston, it is not necessary to provide connecting rods in the axial direction of one crankshaft, and the crankshaft can be provided for the crank The configuration can be such that the axial direction of the shaft falls within the range of the metering unit, so that the positive displacement flow device can be thinned in the axial direction of the crankshaft.

  Also, such a volumetric flow rate detector does not have a structure in which the connecting rods of each weighing unit are connected to the same one crankshaft, and each weighing unit can be separated, so either of the weighings can be performed. If a failure occurs in the unit, it can be easily repaired by replacing the weighing unit.

  Here, in such a positive displacement flow rate detector, the plurality of measuring units are four measuring units, and in the phase difference regulating means, the measuring is such that the phase of rotation of the crankshaft of each measuring unit is adjacent in the forward direction The phase of rotation of the crankshaft of each weighing unit may be regulated so as to be 90 degrees ahead of the phase of rotation of the crankshaft of the unit.

  In this case, the second surface of the cylinder block of each of the weighing units is a plane perpendicular to the direction of the axis of the cylinder internal space of the cylinder block, and the third surface of the cylinder block is the cylinder block The top dead center side opening viewed from the second surface of the cylinder block of each of the weighing units in the axial direction of the cylinder inner space of the weighing unit. Is brought into contact with the third surface of the cylinder block of the weighing unit adjacent to the forward direction so as to overlap the cylinder internal space of the weighing unit adjacent to the forward direction, and the cylinder of the weighing unit The communication hole of the block is a through hole perpendicular to the third surface of the cylinder block, and the communication hole of the cylinder block of each of the weighing units is The surface includes the fourth surface which is a surface perpendicular to the second and third surfaces not in contact with the cylinder block of another measuring unit, and the discharge hole of the cylinder block of each of the measuring units is The fourth surface to the cylinder internal space may be a through hole penetrating perpendicularly to the fourth surface.

By doing so, the length of the communication hole can be made shorter, and the pressure loss of the fluid by the positive displacement flow detector can be made smaller.
Here, the above-mentioned positive displacement flow rate detector may be provided with a torque applying means for applying a torque in the rotational direction to the crankshaft of each of the measuring units.
By doing so, it is possible to cancel the pressure loss by the positive displacement flow rate detector.
The above-described positive displacement flow rate detector includes the phase difference regulating means, individual gears coaxially connected to the crankshafts of the weighing units, provided in each of the weighing units, and It may be formed by a common gear that is a single gear that meshes with the individual gear.

Here, in this case, the positive displacement flow rate detector may be provided with torque applying means for applying torque in the rotational direction to the common gear.
In this way, it is possible to apply torque in the rotational direction to the crankshaft via the common gear and the individual gear, and cancel the pressure loss due to the positive displacement flow detector.
In this case, the common gear has alternating magnetic poles along the circumferential direction, and an annular stator having a plurality of coils disposed so as to surround the outer periphery of the common gear is provided, and the common gear is provided. The motor may be formed as a rotor.

  By doing this, torque in the rotational direction is applied to the crankshaft via the common gear and the individual gear without increasing the axial size of the positive displacement flow detector crankshaft, and the positive displacement flow detector It is possible to cancel the pressure loss due to

As described above, according to the present invention, it is possible to provide a piston type positive displacement flow rate detector with reduced pressure loss.
Further, according to the present invention, it is possible to provide a piston-type positive displacement flow detector having a structure suitable for thinning.
Further, according to the present invention, it is possible to provide a piston-type positive displacement flow detector having a structure that facilitates replacement and repair.

It is a figure which shows the external appearance of the positive displacement flow rate detector based on embodiment of this invention. It is a figure which shows the internal structure of the positive displacement flow rate detector based on embodiment of this invention. It is a figure which shows the structure of the measurement unit of the positive displacement flow rate detector based on embodiment of this invention. It is a figure which shows the structure of the measurement unit of the positive displacement flow rate detector based on embodiment of this invention. It is a figure which shows the structure of the measurement block of the positive displacement flow rate detector based on embodiment of this invention. FIG. 7 is a view showing the operation of the metering block of the positive displacement flow rate detector according to the embodiment of the present invention. It is a figure which shows the mechanism of the rotation detection of the positive displacement flow rate detector based on embodiment of invention. It is a figure which shows the mechanism of the fluid pressurization of the positive displacement flow rate detector based on embodiment of invention. It is a figure which shows the other structural example of the positive displacement flow rate detector based on embodiment of this invention. It is a figure which shows the structure of a well-known positive displacement type flow sensor.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a positive displacement flow rate detector according to the present embodiment.
In FIG. 1, FIG. 1a shows the top of the positive displacement flow detector, FIG. 1b shows the side of the positive displacement flow detector, and FIG. 1c shows the bottom of the positive displacement flow detector. FIG. 1 d also shows the positive displacement flow detector in perspective from above.

As illustrated, the positive displacement flow rate detector according to the present embodiment has a shape in which a rectangular parallelepiped connection portion 100 is connected to the upper surface of the cylindrical main body portion 2.
The connecting portion 100 is a member for connecting an external flow path to the positive displacement flow rate detector, and an upper surface of the connecting portion 100 is provided with an inlet 101 serving as an inlet of fluid to the positive displacement flow rate detector, and a volume An outlet 102 is provided which provides an outlet for fluid from the flow rate detector.

Next, FIG. 2a1 shows a cross section taken along the line AA of FIG. 1a of the positive displacement flow detector, and FIG. 2a shows a cross section taken along the sectional line BB of FIG. 1a of the positive flow detector.
As shown in FIGS. 2a 1, a 2 and FIGS. 1A and 1B, the body portion 2 of the positive displacement flow detector has a hollow cylindrical side cover 21, an upper outer lid 22, an upper inner lid 23 and a lower lid 24. have. The upper cover 22 and the upper inner cover 23 doubly close the opening on the side cover 21 except for the inflow path 201 and the discharge path 202 described later, and the lower cover 24 is a side cover 21. Block the opening below.

And the inflow path 201 mentioned above is a flow path which connects the inside of the enclosed space surrounded by the side cover 21, the upper inner lid 23 and the lower lid 24, and the inflow port 101 of the connecting portion 100. 22 and holes formed in the upper inner lid 23. The discharge path 202 described above is a flow path connecting the inside of the sealed space surrounded by the upper inner lid 23 and the lower lid 24 and the outlet 102 of the connecting portion 100, and in the upper outer lid 22 and the upper inner lid 23. It is formed by the provided hole.
In addition, although illustration is abbreviate | omitted, shield members, such as an O-ring, are arrange | positioned between the members which need sealing of a positive displacement flow detector.

  Further, an electronic circuit board 25 is fixed to the lower part of the lower lid 24. In addition, a hollow cylindrical stator unit 26 is fixedly disposed so as to surround the periphery of the side cover 21.

  Here, FIG. 2 a 3 shows a positive displacement flow detector as viewed from the side with the side cover 21 and the stator unit 26 removed, and FIG. 2 b 1 from the upper side with the connecting portion 100 and the upper outer lid 22 removed. FIG. 2 b 2 shows a view of a positive displacement flow detector as seen, and FIG. 2 b 2 shows a direct view of a positive displacement flow detector as viewed from above with the connection portion 100, the upper cover 22 and the upper inner lid 23 removed. The lid 24 is removed and it looks like a positive displacement flow detector seen from below.

  Further, in a sealed space surrounded by the side cover 21, the upper inner lid 23 and the lower lid 24, an annular member rotatably supported by the side cover 21 and the lower lid 24 with the vertical direction as a rotation axis A measuring block 3 formed by connecting a large gear 27 of internal teeth and four measuring units 30 is disposed.

Here, the configuration of the weighing unit 30 is shown in FIG.
Now, for the sake of convenience, upper, lower, front, rear, left and right shown in the drawing are defined as upper, lower, front, rear, left, and right of the weighing unit 30. 3a shows the left side of the weighing unit 30, FIG. 3b shows the front of the weighing unit 30, FIG. 3c shows the right side of the weighing unit 30, FIG. 3d shows the back of the weighing unit 30, and FIG. The upper surface of the unit 30 is shown and FIG. 3 f shows the lower surface of the weighing unit 30.

  As shown, the weighing unit 30 includes a cylinder block 301, a piston 302, a crankshaft 303, a connecting rod 304, and an external small gear 305.

  The perspective view of the cylinder block 301 is shown to FIG. 4 a1, a2. The cylinder block 301 has a cylinder internal space 3011 which is a cylindrical hole penetrating the cylinder block 301 in the front-rear direction.

Further, the cylinder block 301 is a communication hole 3012 which is a hole penetrating in the left and right direction from the right side surface of the cylinder block 301 to the cylinder internal space 3011 and a hole penetrating in the vertical direction from the upper surface of the cylinder block 301 to the cylinder internal space 3011 A certain outflow hole 3013 is provided, and the cylinder internal space 3011, the communication hole 3012 and the outflow hole 3013 are connected.
It should be noted that in the communication hole 3012 and the outflow hole 3013, the resistance to the fluid passing through the communication hole 3012 and the outflow hole 3013 is smaller than in the vicinity of the cylinder internal space 3011. The diameter in the axial direction of the cylinder internal space 3011 is enlarged.

  The perspective view of piston 302 is shown to FIG. 4 b1 and b2. The piston 302 has a shape with a constriction formed by reducing the diameter at a central portion in the axial direction.

Then, as shown in FIG. 4 c 1, the piston 302 is disposed slidably in the front-rear direction in the cylinder internal space 3011.
The crankshaft 303 is pivotally supported by the cylinder block 301 so as to be rotatable about the vertical direction at a position forward of the cylinder internal space 3011, and the crankshaft 303 and the piston 302 are connected by the connecting rod 304. ing.

  Then, as shown in FIGS. 4 c 1, c 2, c 3 and c 4, the connecting rod 304 interlocks the rotational movement of the crankshaft 303 and the back and forth movement of the piston 302 in the cylinder internal space 3011. That is, when the crankshaft 303 is rotated, the piston 302 reciprocates in the back and forth direction in the cylinder internal space 3011, and when the piston 302 is reciprocated in the back and forth direction in the cylinder internal space 3011, the crankshaft 303 rotates.

Next, the small gear 305 is connected to the crankshaft 303 below the crankshaft 303, and rotates with the crankshaft 303 using the vertical direction as a rotation axis.
The configuration of the weighing unit 30 has been described above.
Now, as described above, although four such weighing units 30 are connected to form the weighing block 3, one of the weighing units 30 is cranked in addition to the configuration shown in FIGS. A magnet for detecting the rotation of the shaft 303 is provided. The magnet is connected below the small gear 305 so as to rotate together with the crankshaft 303 and the small gear 305. The configuration of the magnet and the rotation detection using the magnet will be described later.

Next, the weighing block 3 formed by connecting four weighing units 30 will be described.
FIG. 5a shows a cross section according to the sectional line CC of FIG. 2a1 and FIG. 5b shows a perspective view of the weighing block 3. FIG. In the weighing block 3, the weighing units 30 are arranged in order in the vertical direction so that they coincide with each other in a state in which the vertical heights are aligned around the vertical axis.

  The direction of each weighing unit 30 is 90 degrees in the forward direction relative to the weighing unit 30 adjacent in the reverse direction, with the clockwise direction as viewed from the top of FIG. 5 a as the forward direction and the counterclockwise direction as the reverse direction. It inclines and the surface on the rear side of the cylinder internal space 3011 of each measuring unit 30 abuts on the right side of the adjacent measuring unit 30 in the forward direction. Further, an opening on the rear side of the cylinder inner space 3011 of each of the weighing units 30 is connected to the communication hole 3012 of the weighing unit 30 adjacent in the forward direction. The openings between the adjacent weighing units 30 are shielded, and the opening on the rear side of the cylinder internal space 3011 of each weighing unit 30 and the opening on the right side of the communication hole 3012 are outside the weighing block 3 of the enclosed space. Sealed to the part.

Such a measuring block 3 is fixed in a sealed space surrounded by the side cover 21, the upper inner lid 23 and the lower lid 24 as described above.
Then, as shown in FIG. 2 b 3, the external teeth of the small gears 305 of each of the weighing units 30 mesh with the internal teeth of the large gear 27 in a state where the measuring block 3 is fixed in the enclosed space. Further, the meshing between the small gear 305 and the large gear 27 is such that the rotational phase of the small gear 305 of each weighing unit 30 and the crankshaft 303 is 90 degrees ahead of the weighing unit 30 adjacent in the forward direction. There is.

  Further, in a state where the measuring block 3 is fixed in the enclosed space, as shown in FIG. 2a1, the inflow path 201 communicating with the inflow port 101 of the positive displacement flow detector is the outer peripheral side of the measuring block 3 in the enclosed space. Contact the space of. Further, the discharge passage 202 in communication with the discharge port 102 of the positive displacement flow detector communicates with the outflow hole 3013 of each of the weighing units 30. The space between the upper inner lid 23 and the measuring block 3 is shielded, and the opening of the outflow hole 3013 on the upper surface of the measuring unit 30 and the opening on the closed space side of the discharge passage 202 are outside the measured block 3 of the closed space. Is sealed against the part of

  Now, in such a configuration, when fluid flows in from the inlet 101 of the positive displacement flow detector, the fluid enters the interior of the metering block 3 through the portion outside the metering block 3 of the enclosed space, and the metering block 3 The pressure is applied to the piston 302 of each of the weighing units 30.

  Then, the four pistons 302 of the four measuring units 30 reciprocate with a phase difference of 90 degrees in the order of FIGS. 6a, b, c, d, a, b,... The fluid which has entered the inside of the measuring block 3 is discharged from the discharge port 102. Here, in FIG. 6, the black arrows indicate the moving direction of the piston 302, and the white arrows indicate the fluid flow direction.

  Now, here, as shown in FIGS. 6a, b, c, d, the communication hole 3012 and the outflow hole 3013 of the cylinder block 301 of each measuring unit 30 are located when the piston 302 is located near the bottom dead center. It is provided in the position which becomes in the range of the above-mentioned narrowing of the piston 302 concerned about the axial direction of the piston 302 concerned. Further, the communication hole 3012 of the cylinder block 301 of each measuring unit 30 is provided at a position outside the range of the piston 302 in the axial direction of the piston 302 only when the piston 302 is positioned near the top dead center. When the piston is located near the top dead center, the communication hole 3012 is positioned from the opening on the lower dead center side of the cylinder space than the piston 302, and the lower dead center side of the cylinder space Communicate through the opening and cylinder space. On the other hand, the outflow hole 3013 of the cylinder block 301 of each measuring unit 30 is a position near to the opening on the top dead center side of the cylinder space a little more than the communication hole 3012, regardless of the position of the piston 302. It is provided at a position not out of the range of the piston 302 in the axial direction of 302.

  The fluid that has entered the portion outside the metering block 3 of the enclosed space from the inlet 101 of the positive displacement flow detector is the metering unit 30 (B in FIG. 6a, C in FIG. 6b) where the piston 302 is near top dead center. 6c flows from the opening on the lower dead center side of the piston 302 into the cylinder internal space 3011 of D in FIG. 6D and A in FIG. 6d. And, in the measuring unit 30 in which the piston 302 is in the vicinity of the top dead center, the communication hole 3012 is not sealed by the piston 302 with respect to the space on the lower dead center side than the piston 302 of the cylinder internal space 3011. The cylinder of the metering unit 30 (A in FIG. 6a, B in FIG. 6b, C in FIG. 6c, D in FIG. 6d), with the piston 302 moving towards the bottom dead center, through the hole 3012 and in the opposite direction. It flows into the space on the top dead center side of the piston 302 of the internal space 3011.

  On the other hand, at this time, in the measuring unit 30 other than the measuring unit 30 in which the piston 302 is in the vicinity of the top dead center, the communication hole 3012 with respect to the space on the bottom dead center side of the piston 302 in the cylinder internal space 3011 Because it is sealed, the fluid that has flowed into the cylinder internal space 3011 from the bottom dead center of the piston 302 will not flow into the cylinder internal space 3011 of the metering unit 30 adjacent in the opposite direction.

  Next, in the weighing unit 30 (C in FIG. 6a, D in FIG. 6b, A in FIG. 6c, B in FIG. 6d), the piston 302 has started moving from the bottom dead center to the top dead center. From the forwardly adjacent metering unit 30 (D in FIG. 6a, A in FIG. 6b, B in FIG. 6c, C in FIG. 6d) as described above when the piston 302 is moving towards the bottom dead center The fluid flowing into the space on the top dead center side of the piston 302 in the cylinder interior space 3011 is pushed by the piston 302 in the opening direction on the top dead center side of the cylinder interior space 3011. On the other hand, at this time, the piston 302 of the forwardly adjacent measuring unit 30 is located near the bottom dead center, and the communication hole 3012 and the outflow hole 3013 of the measuring unit 30 are between the central constrictions of the piston 302. positioned. Therefore, in the measuring unit 30 in which the piston 302 starts moving from the bottom dead center to the top dead center, the fluid pushed in the opening direction on the top dead center side of the cylinder internal space 3011 is an opening on the top dead center side. Flowed into the space between the central constrictions of the pistons 302 of the forwardly adjacent measurement units 30 through the communication holes 3012 of the forward adjacent measurement units 30, and flowed into the space between the central constrictions The fluid is discharged from the outlet hole 3013 through the discharge passage 202 and out of the outlet 102 of the positive displacement flow detector. The space between the central neck of the piston 302 is sealed with respect to the space on the top dead center side of the piston 302 and the space on the bottom dead center side.

The crankshaft 303 rotates in conjunction with the above-described reciprocating motion of the piston 302.
Here, since the volume of the fluid discharged from the metering unit 30 to the discharge port 102 is constant per one reciprocation of the piston 302 of each of the metering units 30 as described above, the volume is obtained by one rotation of the crankshaft 303. The flow rate of fluid flowing from the inlet 101 to the outlet 102 through the flow rate detector is constant. Therefore, if the amount of rotation of the crankshaft 303 is detected, it is possible to measure the flow rate of fluid flowing from the inlet 101 to the outlet 102.

Next, detection of rotation of the crankshaft 303 using the above-described magnet will be described.
A magnet 306 is connected to the lower side of the small gear 305 so as to rotate together with the crankshaft 303 and the small gear 305, as shown in FIG. 7 and FIG. 2a2, to one of the four measurement units 30. There is. In addition, the magnet 306 changes its magnetic pole along the circumferential direction.

On the other hand, a magnetic field detection element 251 such as an MR element or a Hall element is disposed at a position on the lower part of the lower lid 24 facing the magnet 306 of the electronic circuit substrate 25. The amount of rotation of the crankshaft 303 is detected by detecting the change in the magnetic field accompanying the.
Then, the flow rate of the fluid passing through the positive displacement flow rate detector by the data processing circuit provided on the electronic circuit board 25 from the rotation amount of the crankshaft 303 and the flow rate of fluid per rotation of the crankshaft 303 of the measuring unit 30 described above. Calculate and output.

However, the amount of rotation of the crankshaft 303 detected by the magnetic field detection element 251 is output from the electronic circuit board 25 to an external data processing device, and the amount of rotation of the crankshaft 303 in the external data processing device The flow rate through the positive displacement flow rate detector may be calculated from the flow rate of fluid per one rotation of the crankshaft 303 of FIG.
Next, in the positive displacement flow detector as described above, the stator unit 26 is provided to apply torque in the rotational direction to the large gear 27 and cancel the influence of pressure reduction by the positive displacement flow detector.

  Here, FIG. 8 shows a part of a cross section taken along the cross sectional line DD of FIG. 2a1. A magnet 271 is disposed on the outer peripheral side of the large gear 27 so that the magnetic pole changes along the circumferential direction. Alternatively, the outer peripheral portion of the large gear 27 is magnetized so that the magnetic pole changes along the circumferential direction.

Then, in the portion of the stator unit 26 facing the large gear 27, a plurality of coils 261 having alternating phases are arranged in the circumferential direction.
With the above-described configuration, a motor having the stator unit 26 as a stator and the large gear 27 as a rotor is configured.
Therefore, by driving the stator unit 26, it is possible to apply a torque for rotating the large gear 27. This torque is transmitted from the large gear 27 to the small gear 305 of each measuring unit 30, the crankshaft 303, and each measuring unit The 30 pistons 302 are driven to pressurize the fluid discharged from each of the metering units 30.

  Here, by thus providing the stator unit 26 on the outer peripheral side of the large gear 27 and forming a motor having the large gear 27 as a rotor, the axial size of the crankshaft 303 of the positive displacement flow detector is determined. Without increasing the size, torque in the rotational direction can be applied to the crankshaft 303 of each weighing unit 30 to pressurize the fluid discharged from each weighing unit 30.

  The control of the drive of the stator unit 26 is, for example, a drive of the stator unit 26 such that the difference between the pressure of the fluid flowing into the positive displacement flow rate detector and the pressure of the fluid discharged from the positive displacement flow rate detector is eliminated. Is performed by servo control.

The positive displacement flow rate detector according to the present embodiment has been described above.
By the way, in the above embodiment, when it is not necessary to cancel the influence of the pressure reduction by the positive displacement flow rate detector, the stator unit 26 is not necessary. Further, it is not necessary to provide or magnetize the magnet 271 on the large gear 27.

  In this case, the large gear 27 is meshed with the four small gears 305 of the four weighing units 30, as shown by a positive displacement flow detector as viewed from below with the lower cover 24 removed in FIG. It may be a gear provided with teeth.

  As described above, according to the present embodiment, the length of the communication hole 3012 for transferring the fluid between the cylinder inner space 3011 can be shortened, thereby reducing the pressure loss of the fluid by the positive displacement flow rate detector. it can.

  In addition, since the crankshaft 303 is provided for each piston 302, there is no need to provide the connecting rod 304 in the axial direction of the crankshaft 303, and the positive displacement flowmeter can be thinned in the axial direction of the crankshaft 303. it can.

Also, since the connecting rods 304 of each weighing unit 30 are not connected to the same crankshaft, and each weighing unit 30 is separable, if any weighing unit 30 breaks down, weighing can be easily performed. Repairs can be made by replacing unit 30.
In the above embodiment, the rotational phase of the crankshaft 303 of each weighing unit 30 is advanced by 90 degrees relative to the weighing unit 30 adjacent in the forward direction by the mechanism of the small gear 305 and the large gear 27 of each weighing unit 30. However, the regulation of the rotational phase of the crankshaft 303 of each of the weighing units 30 may be realized by another mechanism such as a mechanism using a timing belt and a pulley.

  DESCRIPTION OF SYMBOLS 2 ... Body part, 3 ... Measurement block, 21 ... Side cover, 22 ... Upper outer lid, 23 ... Upper inner lid, 24 ... Lower lid, 25 ... Electronic circuit board, 26 ... Stator unit, 27 ... Large gear, 30 ... measuring unit, 100 ... connecting part, 101 ... inlet, 102 ... outlet, 201 ... inlet, 202 ... outlet, 251 ... magnetic field detecting element, 261 ... coil, 271 ... magnet, 301 ... cylinder block, 302 ... 302 Piston, 303: Crankshaft, 304: Connecting rod, 305: Small gear, 306: Magnet, 3011: Internal space of cylinder, 3012: Communication hole, 3013: Effusion hole.

Claims (7)

A positive displacement flow detector having an inlet and an outlet and detecting a flow rate of fluid flowing from the inlet to the outlet,
A weighing block having a plurality of weighing units disposed in the enclosed space;
Rotation detection means;
And phase difference regulation means,
Each of the measuring units includes a cylinder block provided with a cylinder internal space, a piston having a central narrow portion in the axial direction sliding on the cylinder internal space, and a crankshaft supported by the cylinder block. A connecting rod that connects the crankshaft and the piston and interlocks the reciprocating motion between the bottom dead center and the top dead center in the cylinder internal space of the piston and the rotational motion of the crankshaft;
The cylinder block has an outer surface including a first surface, a second surface, and a third surface,
The cylinder internal space is a through hole having the bottom dead center side opening which is an opening of the first surface into which the connecting rod is inserted and the top dead center side opening which is an opening of the second surface as openings at both ends. Yes,
The cylinder block has a communication hole which is a hole penetrating from the third surface to the cylinder internal space, and a discharge hole which is a hole penetrating from the outer surface to the cylinder internal space,
An opening on the cylinder internal space side of the communication hole and the discharge hole is a position that falls within the range of the constriction of the piston in the axial direction of the piston when the piston of the weighing unit is positioned near the bottom dead center. In
The opening on the cylinder internal space side of the communication hole, when the piston of the metering unit is located near the top dead center, the bottom dead center side opening of the piston in the axial direction relative to the range of the piston At least a part of which is outside the range of the piston in the axial direction of the piston only when the piston is positioned near the top dead center,
The opening on the cylinder internal space side of the discharge hole is a position closer to the top dead center side opening than the opening on the cylinder internal space side of the communication hole, and always in the axial direction of the piston Provided at a position that is within the range,
The plurality of weighing units are sequentially and cyclically arranged adjacent to each other so as to form a loop of the plurality of weighing units.
The second surface of the cylinder block of each of the weighing units is ordered in a first direction advancing along the loop as a forward direction and a direction advancing along the loop opposite to the first direction is an opposite direction. In contact with the third surface of the cylinder block of the metering unit adjacent in the direction,
The opening on the third surface side of the communication hole of the cylinder block of each weighing unit is provided at a position overlapping the top dead center opening of the weighing unit adjacent in the reverse direction,
The opening on the outer surface side of the discharge hole of the cylinder block of each measuring unit is provided in a portion of the outer surface not in contact with the cylinder block of the other measuring unit,
An opening on the outer surface side of the discharge hole of each of the weighing units is in communication with the discharge port,
The bottom dead center side opening of the cylinder block of each of the weighing units is in communication with the inlet;
The phase difference regulation means rotates the crankshaft of each weighing unit such that the phase of rotation of the crankshaft of each weighing unit advances by a predetermined angle from the phase of rotation of the crankshaft of the weighing unit adjacent in the forward direction. Regulate the phase of
The positive displacement flow detector according to claim 1, wherein the rotation detecting means detects an amount of rotation of a crankshaft of at least one of the weighing units.
The positive displacement flow detector according to claim 1, wherein
As the plurality of weighing units, four weighing units are provided,
The phase difference restricting means sets the phase of the rotation of the crank shaft of each of the weighing units to be 90 degrees ahead of the rotation of the crank shaft of the weighing units adjacent in the forward direction. A positive displacement flow detector characterized in that the phase of rotation of a crankshaft is regulated.
The positive displacement flow detector according to claim 2, wherein
The second surface of the cylinder block of each of the weighing units is a plane perpendicular to the direction of the axis of the cylinder internal space of the cylinder block, and the third surface of the cylinder block is the interior of the cylinder of the cylinder block A plane parallel to the direction of the space axis,
When viewed in the axial direction of the cylinder interior space of the weighing unit, the second top surface of the cylinder block of the weighing unit overlaps the cylinder interior space of the weighing unit adjacent in the forward direction with the top dead center side opening In contact with the third surface of the cylinder block of the weighing unit adjacent in the forward direction so as to be in position;
The communication hole of the cylinder block of each of the weighing units is a through hole perpendicular to the third surface of the cylinder block,
The outer surface of the cylinder block of each of the weighing units includes a fourth surface which is a surface perpendicular to the second and third surfaces which do not abut the cylinder block of the other weighing units,
The positive displacement flow detector is characterized in that the discharge hole of the cylinder block of each of the measuring units is a through hole which penetrates vertically from the fourth surface to the cylinder internal space.
The volumetric flow detector according to claim 1, 2 or 3, wherein
A positive displacement flow detector comprising torque applying means for applying torque in the rotational direction to the crankshaft of each of the measuring units.
The volumetric flow detector according to claim 1, 2 or 3, wherein
The phase difference regulating means is provided on each of the respective weighing units, and has a single gear coaxially connected to the crankshaft of the weighing unit and a single gear meshing with the individual gear of each of the weighing units. A positive displacement flow detector comprising:
The positive displacement flow detector according to claim 5, wherein
A positive displacement flow detector comprising torque applying means for applying torque in the rotational direction to the common gear.
The positive displacement flow detector according to claim 5, wherein
In the common gear, magnetic poles alternate along the circumferential direction,
The positive displacement flow detector includes an annular stator having a plurality of coils disposed so as to surround the outer periphery of the common gear;
A positive displacement flow rate detector characterized in that the stator comprises a motor with the common gear as a rotor.