JP6787733B2 - Flow control damper - Google Patents

Description

The present invention relates to a flow control damper.

Various dampers are used in the air conditioning equipment (see, for example, Patent Document 1-2).

Japanese Unexamined Patent Publication No. 2014-170529 Japanese Unexamined Patent Publication No. 2015-21652

The flow rate control damper adjusts the opening degree according to the flow rate of the fluid passing through the damper. Therefore, if the flow rate is not measured properly, the opening degree adjustment of the flow rate control damper becomes unstable. Therefore, it is desired to optimize the flow rate measurement in the flow control damper, but the fluid passing through the flow control damper is a drift or turbulence due to the shape of the duct on the upstream side, and an air flow due to the angle of the blades of the flow control damper. May be disturbed. In this case, in the differential pressure type flow meter, the pressure measurement at the pressure measuring port provided on the inner wall surface of the flow path before and after the damper may vary, and the measured flow rate may become unstable. In particular, the turbulence of the airflow caused by the angle of the blades of the flow control damper becomes remarkable as the opening of the damper approaches the closed state, and the turbulence of the airflow tends to appear remarkably in the state close to the fully closed state. Such turbulence of the airflow in the flow control damper whose angle changes frequently has a great influence on the control characteristics.

Therefore, the present application discloses a flow rate control damper that suppresses fluctuations in the measured flow rate due to the shape of the upstream duct and the angle of the blades as much as possible.

In order to solve the above problems, the flow rate control damper disclosed in the present application is provided with a partition between a pair of movable blades that control the flow rate by increasing or decreasing the distance between them, and a flow path is provided on the upstream side of the pair of movable blades. It was decided to measure the flow rate by the differential pressure obtained through the holes provided on the outer peripheral surface of the pipe arranged so as to cross and the holes provided on the blade surface of the partition.

Specifically, the flow control damper disclosed in the present application is a casing connected to a duct to form a fluid flow path, and blades of an opposing wing that controls the flow rate by increasing or decreasing the distance between each other in the casing. A pair of movable blades with a sharp edge cross-sectional shape and a pipe arranged so as to cross the flow path on the upstream side of the pair of movable blades, and are the first pressure measurement used for pressure measurement of a differential pressure type pressure gauge. A plate-shaped member that divides the flow path between a pair of movable blades into one movable blade side and the other movable blade side, and is a differential pressure type flow meter. It is provided with a partition having a second pressure measuring hole on the blade surface used for the pressure measurement of the above.

In the above flow control damper, the first pressure measurement hole used for pressure measurement on the upstream side of the differential pressure type pressure gauge is arranged so as to cross the flow path on the upstream side of the pair of movable blades. It is provided on the outer peripheral surface. Therefore, for example, even if there is an elbow in the upstream duct and a drift is generated, the pressure on the upstream side of the differential pressure type flow meter is properly detected.

Further, in the above-mentioned flow control damper, the fluid that has passed between the pair of movable blades flows along the blade surface of the partition without being separated from the partition at least regardless of the angle of the movable blades. Further, in the above-mentioned flow control damper, since the cross-sectional shape of the leading edge of the movable blade is an acute angle, the fluid is quickly separated from the movable blade at the leading edge of the movable blade, and easily flows along the blade surface of the partition. Therefore, the fluid flow passing between the pair of movable blades is more stable than when there is no partition. If the airflow of the fluid passing between the pair of movable blades is stable, the pressure on the downstream side of the differential pressure type pressure gauge obtained through the holes for pressure measurement provided on the blade surface of the partition can be properly detected. Therefore, fluctuations in the measured flow rate due to the shape of the upstream duct and the angle of the blades are suppressed.

In the above flow control damper, both the pressure on the upstream side and the pressure on the downstream side of the pair of movable blades are properly detected as described above, and as a result, the differential pressure is also properly detected. , Fluctuations in the measured flow rate due to the shape of the upstream duct and the angle of the blades will be suppressed as much as possible.

The first pressure measurement hole may be opened in the upstream direction of the flow path. If the first pressure measuring hole is formed in this way, the total pressure on the upstream side of the movable blade can be measured.

Further, the pressure detection tube may have a plurality of holes for the first pressure measurement, or is arranged on each upstream side of the two flow paths between the pair of movable blades partitioned by the partition. It may be. If such a pressure detection tube is provided in the flow rate control damper, an average pressure can be obtained through a plurality of holes, so that a stable measured flow rate can be obtained.

Further, the partition is a plate-shaped member formed of a hollow member, and the second pressure measurement hole may be formed so as to communicate with the inside and outside of the partition, or from the upstream side to the downstream side. It may have a wing-shaped portion having a wing-shaped cross-sectional shape, which is gradually reduced in thickness toward the end. A flow rate control damper provided with such a partition can obtain a more stable measured flow rate than, for example, when pressure is detected through pores formed on the casing surface.

Further, the second pressure measurement hole may be formed on an inclined surface whose thickness gradually decreases from the upstream side to the downstream side. Further, the partition may have a slat portion formed so as to protrude in the upstream direction from the leading edge of the airfoil portion. With such a flow rate control damper, the fluid passing between the pair of movable blades easily flows along the blade surface of the partition, so that the airflow is stable and an appropriate pressure can be measured.

The above-mentioned flow rate control damper can suppress fluctuations in the measured flow rate due to the shape of the upstream duct and the angle of the blades as much as possible.

FIG. 1 is a diagram showing a flow rate control damper according to the embodiment. FIG. 2 is a diagram showing the internal structure of the flow rate control damper according to the embodiment. FIG. 3 is a diagram showing the structure of the partition. FIG. 4 is a diagram showing the effect of the partition on the air flow. FIG. 5 is a diagram showing variations in drift. FIG. 6 is a diagram showing the analysis result of the air flow. FIG. 7 is a structural diagram of a mounting portion of the partition. FIG. 8 is a diagram showing a mounting portion of a partition during mounting. FIG. 9 is a diagram showing the size relationship between the plate material and the mounting hole. FIG. 10 is a diagram showing a control system of the flow rate control damper. FIG. 11 is a diagram illustrating the operation of the movable blade. FIG. 12 is a diagram illustrating the operation of the movable blade when the drive mechanism according to the comparative example is adopted. FIG. 13 is a diagram showing a state of airflow when the opening degrees of the two movable blades do not match. FIG. 14 is a diagram showing a state of airflow when the opening degrees of the two movable blades match. FIG. 15 is a diagram showing a comparative example of the flow rate control damper. FIG. 16 is a diagram showing the position of the pressure measuring port. FIG. 17 is a graph showing the verification results. FIG. 18 is a diagram showing a pattern of drift in the present verification.

Hereinafter, embodiments of the present invention will be described. The embodiments shown below are examples of embodiments of the present invention, and the technical scope of the present invention is not limited to the following embodiments.

FIG. 1 is a diagram showing a flow rate control damper according to the embodiment. Further, FIG. 2 is a diagram showing an internal structure of the flow rate control damper according to the embodiment.

The flow rate control damper 1 of the present embodiment is an air conditioning damper that can be attached to a square air conditioning duct, and includes a square casing 10. The casing 10 is a hollow housing that exhibits a substantially cubic shape. The casing 10 has an opening 11F that completely opens one surface of the housing, and an opening 11R that completely opens one surface of the housing on the opposite side of the opening 11F. It is a casing that substantially has a frame-like shape when viewed along the direction of. The casing 10 is provided with a flange 12F for connecting to an air conditioning duct located on the opening 11F side along the edge of the opening 11F. Further, the casing 10 is provided with a flange 12R along the edge of the opening 11R for connecting to the air conditioning duct located on the opening 11R side. The upstream portion of the air conditioning duct is connected to the opening 11F, and the downstream portion of the air conditioning duct is connected to the opening 11R, so that the fluid flowing through the air conditioning duct flows into the casing 10 through the opening 11F, and the opening It will flow out of the casing 10 through 11R.

Movable blades 20a, 20b, a partition 30 (an example of a "partition" in the present application), pressure detection tubes 40a, 40b, and guide members 50aF, 50aR, 50bF, 50bR are provided inside the casing 10. .. Further, on the outside of the casing 10, a drive device 60 for moving the movable blades 20a and 20b is provided.

The movable blade 20a is a blade that rotates about a rotating shaft 21a, and as shown in FIG. 2, a plate-shaped side surface portion 22a and a side surface portion 22a having a shape that spreads like a fan from the rotating shaft 21a. It has a blade portion 23a that is fixed to the arc portion and forms a blade surface parallel to the rotation shaft 21a. The blade portion 23a has a flat surface 24a that directs a flat surface toward the rotation shaft 21a. Further, the blade portion 23a has a curved surface 25a curved along the arc of the fan-shaped side surface portion 22a on the back side of the flat surface 24a. The cross-sectional shape of the blade portion 23a is a half-moon shape. The blade portion 23a has an acute angle so that the fluid passing through the leading edge can easily be separated from the flat surface 24a in the cross-sectional shape of the leading edge, which is a portion where the curved surface 25a and the flat surface 24a are adjacent to each other. Like the movable blade 20a, the movable blade 20b is a blade that rotates about the rotating shaft 21b, and is a blade of an opposing blade that faces the movable blade 20a. Like the movable blade 20a, the movable blade 20b also has a blade portion 23b having a flat surface 24b and a curved surface 25b, and a side surface portion 22b to which the blade portion 23b is fixed. The cross-sectional shape of the blade portion 23b is a half-moon shape like the blade portion 23a. Then, by rotating the movable blades 20a and 20b and adjusting them to an appropriate angle, the magnitude of the exposure amount of the curved surfaces 25a and 25b to the flow path in the casing 10 changes, and the flow in the casing 10 The cross-sectional area of the road increases or decreases. The movable blades 20a and 20b rotate so that the curved surfaces 25a and 25b are exposed on the upstream side of the air flow. Further, when closing the flow path, the movable blades 20a and 20b rotate so that the leading edges of the blade portions 23a and 23b approach the partition 30.

The guide member 50aF is a member that prevents the airflow from colliding with the blade portion 23a when the flow control damper 1 is fully open, and the flat surface 24a of the movable blade 20a in which the fluid flowing into the casing 10 from the opening 11F is fully open. It is a member that rises from the inner surface of the casing 10 on the upstream side of the blade portion 23a so as to flow along the above. Further, the guide member 50aR is a member that prevents turbulence from occurring on the downstream side of the blade portion 23a when the flow control damper 1 is fully open, and the fluid that has passed through the flat surface 24a does not separate and smoothly reaches the opening 11R. It is a member that rises from the inner surface of the casing 10 on the downstream side of the blade portion 23b so as to flow into the casing 10. Like the guide members 50aF and 50aR, the guide members 50bF and 50bR are members located in front of and behind the blade portion 23b when the flow rate control damper 1 is fully opened. The guide members 50aF and 50bF are provided with gaskets 51aF and 51bF made of an elastic body such as rubber, respectively. The tips of the gaskets 51aF and 51bF are in constant contact with the movable blades 20a and 20b when the movable blades 20a and 20b move between the fully closed position and the fully open position. Therefore, when the airflow passes through the flow rate control damper 1, it does not pass between the movable blade 20a and the guide member 50aF, and between the movable blade 20b and the guide member 50bF, so that more stable pressure measurement can be performed. The gaskets 51aF and 51bF are preferably made of Teflon (registered trademark) when there is a possibility of being corroded by the fluid passing through the flow control damper 1.

The pressure detection pipe 40a and the pressure detection pipe 40b are hollow pipes provided on the opening 11F side of the casing 10. The pressure detection tube 40a and the pressure detection tube 40b are provided on the upstream side of the movable blades 20a and 20b in the fully closed position of the movable blades 20a and 20b. Further, the pressure detection tube 40a and the pressure detection tube 40b are arranged in parallel along the direction crossing the flow path, and a plurality of pores 41aF, 41bF (in the present application) that open toward the upstream direction of the flow rate control damper 1. (An example of a "first pressure measuring hole") is provided at equal intervals along the longitudinal direction of the pipe. One end of the pressure detection tube 40a communicates with the tube connection port 42aF provided on the side surface of the casing 10, and one end of the pressure detection tube 40b communicates with the tube connection port 42bF provided on the side surface of the casing 10. Then, a tube connected to a fine differential pressure sensor for measuring the flow rate of the fluid passing through the flow rate control damper 1 is connected to the tube connection port 42aF and the tube connection port 42bF, respectively. Therefore, the pressure detection pipe 40a and the pressure detection pipe 40b function as conduits for detecting the upstream pressure (total pressure = dynamic pressure + static pressure) of the differential pressure type flow meter. The pressure detection tube 40a also functions as a header for averaging the pressures obtained from the plurality of pores 41aF. The pressure detection tube 40b is the same as the pressure detection tube 40a. The pressure detection tubes 40a and 40b are provided over the entire width of the flow path, and are provided at positions that equally divide the vertical direction of the flow path. Further, pores 41aF and 41bF are formed in the pressure detection tubes 40a and 40b at equal intervals over the entire width of the flow path. With such a configuration, it is possible to accurately detect the pressure even if there are various biases in the airflow flowing into the flow path from the upstream side of the movable blades 20a and 20b.

The partition 30 is a plate-shaped member, and is arranged in the casing 10 in a state where the flow path between the movable blades 20a and the movable blades 20b is divided into two on the movable blades 20a side and the movable blades 20b side. ing. The partition 30 has an airfoil portion 31 whose thickness gradually decreases from the upstream side to the downstream side, and whose cross-sectional shape is an airfoil shape. The partition 30 is provided with inclined surfaces 31Ra and 31Rb whose thickness gradually decreases from the upstream side to the downstream side on both the upper and lower wing surfaces of the intermediate partition 30. Since the partition 30 has inclined surfaces 31Ra and 31Rb whose thickness gradually decreases from the upstream side to the downstream side, the partition 30 does not peel off from the blade surface including the pressure detection port even if the flow velocity of the air flow increases. Such an air flow can be formed along both wing surfaces of the partition 30. Further, the upper and lower front edge sides of the airfoil portion 31 are formed so that the thickness increases from the upstream side to the downstream side. The airflow separated from the blades 23a and 23b bends in the directions of the flat surfaces 24a and 24b, respectively, but flows along the increasing surfaces 31Fa and 31Fb of the airfoil portion 31, so that the airflow separated from the blades 23a and 23b Is easily attached to the partition 30. Further, the partition 30 has a slat portion 32 formed so as to protrude in the upstream direction from the leading edge of the airfoil portion 31. The leading edge of the slat portion 32 is manufactured so as to protrude upstream from the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b when the flow control damper 1 is fully closed.

FIG. 3 is a diagram showing the structure of the partition 30. The airfoil portion 31 of the partition 30 is hollow, and a plurality of pores 33aR are formed on the inclined surfaces 31Ra and 31Rb of the upper and lower airfoil surfaces whose thickness gradually decreases from the upstream side to the downstream side. , 33bR (an example of the "second pressure measurement hole" in the present application) is provided. One end of the partition 30 communicates with a tube connection port (not shown) provided on the side surface of the casing 10, and is connected to a fine differential pressure sensor (not shown) for flow rate measurement via a tube attached to the tube connection port. There is. Since the pores 33aR and 33bR are pores that open laterally with respect to the inflow direction of the fluid, the partition 30 functions as a conduit for detecting the downstream pressure (static pressure) of the differential pressure type flow meter. The partition 30 also functions as a header for averaging the pressures of the plurality of pores 33aR and 33bR.

Further, the partition 30 has the following functions. FIG. 4 is a diagram showing the effect of the partition 30 on the air flow. If the flow control damper 1 is opened even slightly, the fluid flowing into the casing 10 passes through the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b. If the flow control damper 1 is not fully open but has an intermediate opening (for example, between several% and about 70%), the fluid that has passed through the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b Since the blades 23a and 23b are separated without flowing along the planes 24a and 24b, the airflow is not stable if there is no member for controlling the airflow such as the partition 30. For example, as shown in FIG. 4B, when a fluid in a rectified state with no bias in the flow velocity flows in, if there is no partition 30, the two blade portions 23a and 23b are slightly as described later. Due to the difference in the positional relationship, the fluid that has passed through the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b flows in an unexpected direction. Further, as shown in FIG. 4D, when a fluid in a drifting state in which the blade portion 23a side is faster than the blade portion 23b side flows in, the leading edge and the blade of the blade portion 23a are provided without the partition 30. The fluid that has passed through the gap with the leading edge of the portion 23b flows to the rear of the blade portion 23b. On the other hand, if the partition 30 is provided, as shown in FIGS. 4A and 4C, the fluid that has passed through the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b is inside. Since it flows along the blade surface of the partition 30, the air flow is stable. In particular, in the flow control damper 1 of the present embodiment, the cross-sectional shape of the leading edge of each blade portion 23a, 23b is sharp so that the fluid can be easily separated from the planes 24a, 24b of the blade portions 23a, 23b. , The fluid separated at the leading edges of the blade portions 23a and 23b easily flows along the blade surface of the partition 30.

The airflow flows so that the same pressure can be detected regardless of whether or not the fluid flowing in between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b is drifting. In this way, when the gas flow passing through the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b is stabilized, the downstream pressure (static pressure) of the differential pressure type flowmeter can be appropriately detected. .. That is, when a hole for detecting static pressure is provided at an appropriate position on the downstream side of the gap between the leading edge of the blade 23a and the leading edge of the blade 23b, the leading edge of the blade 23a and the blade If the fluid that has passed through the gap with the leading edge of the portion 23b does not flow stably, the static pressure detected through the hole will not be stable. On the other hand, if the airflow of the fluid passing through the gap between the leading edge of the blade portion 23a and the leading edge of the blade portion 23b is stable, the static pressure detected through the hole is also stable. In particular, in the flow rate control damper 1 of the present embodiment, the static pressure is detected through the pores 33aR and 33bR provided on the blade surface of the partition 30 that stabilizes the air flow, so that it is provided on the inner surface of the casing 10, for example. A more stable measurement flow rate can be obtained than when static pressure is detected through the pores. If the detected value of the differential pressure is stably obtained even if the opening degree of the flow rate control damper 1 changes, the correlation between the opening degree of the flow rate control damper 1 and the indicated value of the flow meter is uniquely determined. Appropriate control of the control damper 1 is possible.

Although FIG. 4 shows a state in which the blade portion 23a side is faster than the blade portion 23b side as an example of the drift, the partition 30 does not exert a rectifying effect only for such a drift. FIG. 5 is a diagram showing variations in drift. The partition 30 exerts a rectifying effect against a drift in a state where the blade portion 23a side is faster than the blade portion 23b side as shown in FIG. 5A, and the flow rate control damper 1 is used, for example, due to construction reasons. By installing the blades upside down, the same rectifying effect is exhibited even for a drift in a state where the blade portion 23b side is faster than the blade portion 23a side as shown in FIG. 5 (B). Therefore, in the flow control damper 1 of the present embodiment, the static pressure detected through the pores 33aR and 33bR provided on the blade surface of the partition 30 does not differ depending on the damper installation direction with respect to the duct shape on the upstream side. ..

FIG. 6 is a diagram showing the analysis result of the air flow. For example, when the airflow flows from the corner portion of the duct to the flow rate control damper (see FIGS. 6A and 6B), and when the airflow flows from the branch portion of the duct to the flow rate control damper (FIGS. 6C and 6D). ), The drift on the upstream side (primary side) of the flow control damper is larger when flowing from the branch portion than when flowing from the corner portion. However, the drift on the downstream side (secondary side) of the flow control damper having a partition (see FIGS. 6A and 6C) is the drift on the downstream side of the flow control damper without a partition (FIG. 6B). ) (See (D)). When there is a partition, the airflow flows along the partition. Therefore, if the pressure measuring hole provided in the partition is used, the pressure can be detected stably and the control of the flow rate control damper is stable.

By the way, in the description of the above-described embodiment, the attachment structure of the partition 30 is not mentioned, but the partition 30 can be attached to the casing 10 as follows, for example. FIG. 7 is a structural diagram of a mounting portion of the partition 30. Further, FIG. 8 is a diagram showing a mounting portion of the partition 30 during mounting. In FIG. 8, a part of the flange 12F is cut out so that the mounting portion can be easily seen. The partition 30 is a hollow member whose both ends are open. Therefore, if there is a gap in the attachment portion at the end of the partition 30, a micro differential pressure sensor that connects the end of the partition 30 through the tube connection port 36, the tube, or the like is provided on the blade surface of the partition 30. The static pressure of the pores 33aR and 33bR cannot be obtained. Therefore, for example, as shown in FIG. 7, a flat plate material 34 having a size covering the end portion of the partition 30 is prepared, and a gasket 35 more flexible than the plate 34 is provided between the plate 34 and the partition 30. By covering the end portion of the partition 30 with the plate material 34 in such a way as to sandwich it, it is possible to suppress the possibility that a gap is formed in the attachment portion of the end portion of the partition 30.

Further, a mounting hole 13 slightly larger than the cross-sectional shape of the partition 30 and smaller than the plate material 34 is provided in the mounting portion of the partition 30 in the casing 10, and the mounting hole 13 is closed with the gasket 35 and the plate material 34. By doing so, the possibility that a gap communicating with the inside and outside of the casing 10 is generated at the mounting portion of the partition 30 and a gap communicating with the inside of the partition 30 and the inside of the casing 10 is suppressed as much as possible. can do. FIG. 9 is a diagram showing the size relationship between the plate member 34 and the mounting hole 13. If a mounting hole 13 larger than the cross-sectional shape of the partition 30 and smaller than the plate material 34 is provided in the mounting portion of the partition 30 in the casing 10 and the mounting hole 13 is closed with the gasket 35 and the plate material 34, the partition 30 can be mounted. There is almost no possibility that a gap leading to the inside and outside of the casing 10 will occur in the portion.

The drive system of the drive device 60 or the like that moves the movable blades 20a and 20b has the following mechanism. FIG. 10 is a diagram showing a control system of the flow rate control damper 1. Further, FIG. 11 is a diagram illustrating the operation of the movable blades 20a and 20b. The drive device 60 has a built-in stepping motor 61 that is directly connected to the rotating shaft 21a of the movable blade 20a. Movable blade 20
A fan-shaped gear 62a that spreads in a fan shape at an angle of about 90 degrees, which is the same as the movable angle of the movable blade 20a, is fixed to the rotating shaft 21a of a. A fan-shaped gear 62b having the same diameter as the gear 62a is also fixed to the rotating shaft 21b of the movable blade 20b. The gear 62a and the gear 62b are in mesh with each other. Therefore, when the stepping motor 61 rotates the rotation shaft 21a, the movable blades 20a and the movable blades 20b rotate at the same angle in the alternating rotation directions as shown in FIG. The term "rotation" as used in the present application means a movement centered on a rotation axis, and is not limited to a movement that exceeds one revolution around the rotation axis.

As shown in FIG. 10, the stepping motor 61 moves the rotation shaft 21a so as to have an angle θ commanded by the controller 70 that controls the flow control damper 1. The controller 70 is a control device for air conditioning installed near the flow control damper 1, and is derived from a command device such as a host device or a hand switch that controls the entire air conditioning equipment of the facility where the flow control damper 1 is installed. the difference between the airflow setpoint _{Q SP} sent, the pressure sensing tube 40a of the pores 41aF and pressure sensing tube 40b of the pores of the total pressure and medium divider 30 obtained through pores 41Bf 33aR, a static pressure obtained through 33bR The angle θ commanded to the controller 70 is calculated based on the difference from the actual air volume value obtained from the pressure ΔP. The differential pressure ΔP is obtained from the micro differential pressure sensor 71 connected to the tubes 36t and 42t connected to the tube connection ports 36, 42aF and 42bF.

Since the flow rate control damper 1 of the present embodiment employs the drive mechanism 60 as described above, for example, the angle of the movable blade 20b can be adjusted as compared with the case where the drive mechanism according to the following comparative example is adopted. It can be adjusted more precisely. FIG. 12 is a diagram illustrating the operation of the movable blades 20a and 20b when the drive mechanism according to the comparative example is adopted. For example, in the case of a drive mechanism in which the rotating shaft 21b is made to follow the movement of the rotating shaft 21a by a link mechanism, the angle of the movable blade 20b is set to the angle of the movable blade 20a, although it depends on the length and rigidity of the link and the machining accuracy of the connecting portion. Matching is not technically easy. Therefore, for example, the angle of the movable blade 20b may be 85 degrees even though the opening degree is fully open and the angle of the movable blade 20a is 90 degrees.

In the flow rate control damper 1 of the present embodiment, in order to optimize the flow rate measurement, a partition 30 that divides the flow path between the movable blades 20a and the movable blades 20b is adopted, so that the two movable blades 20a are used. If the openings of 20b and 20b do not match, each airflow flowing through the two flow paths partitioned by the partition 30 may become unbalanced. Such an imbalance of airflow is remarkable when the opening degree of the damper is close to fully closed. For example, when the angle of the movable blade 20b is 7 degrees even though the angle of the movable blade 20a is 10 degrees, the following airflow imbalance occurs.

FIG. 13 is a diagram showing a state of airflow when the opening degrees of the two movable blades 20a and 20b do not match. Further, FIG. 14 is a diagram showing a state of airflow when the opening degrees of the two movable blades 20a and 20b are the same. For example, as shown in FIG. 13, when the angle of the movable blade 20b is slightly smaller than that of the movable blade 20a whose angle is adjusted by the stepping motor 61, the gap between the front edge of the movable blade 20b and the partition 30 Is narrower than the gap between the front edge of the movable blade 20a and the partition 30, and the flow rate of the fluid flowing on the movable blade 20b side is smaller than the flow rate of the fluid flowing on the movable blade 20a side. When such an airflow imbalance occurs, the pressure of the gas passing through the pores 33aR and the pressure of the gas passing through the pores 33bR become unbalanced, which may make the measurement of static pressure in the differential pressure type flow meter unstable. There is. The instability of static pressure measurement caused by the imbalance of airflow is noticeable when the damper opening is near fully closed. On the other hand, in the flow control damper 1 according to the present embodiment, the movable blades 20b are adapted to follow the movement of the movable blades 20a by the gears 62a and 62b, and the amount of angular deviation is larger than that of the link mechanism method of the comparative example. small. Therefore, for example, as shown in FIG. 14, the flow rate of the fluid flowing on the movable blade 20b side is substantially the same as the flow rate of the fluid flowing on the movable blade 20a side. Therefore, the measurement of static pressure in the differential pressure type flow meter is stable.

In the flow rate control damper 1 of the present embodiment, the difference between the total pressure obtained through the pores 41aF of the pressure detection tube 40a and the pores 41bF of the pressure detection tube 40b and the static pressure obtained through the pores 33aR and 33bR of the partition 30 Since the pressure ΔP is used, it is important to appropriately set the position for detecting the static pressure obtained through the pores 33aR and 33bR of the partition 30.

FIG. 15 is a diagram showing a comparative example of the flow rate control damper. The flow rate control dampers 101A, 101B, 101C, and 101D according to the comparative example all have movable blades 120a, 120b having an obtuse angle in the leading edge, unlike the movable blades 20a, 20b of the flow rate control damper 1 according to the above embodiment. Be prepared. Further, the flow rate control dampers 101A, 101B, 101C, 101D according to the comparative example include the partition 30A, 130B, 130C, 130D having a different shape from the partition 30 of the flow control damper 1 according to the above embodiment. The partition 130A included in the flow control damper 101A is a mere plate material whose cross-sectional shape is not a blade shape. Further, the intermediate partition 130B included in the flow control damper 101B has the same cross-sectional shape as the intermediate partition 30, but the front and rear are reversed so as to gradually increase in thickness from the front edge side to the rear edge side, and the movable blade 120a , 120b is located upstream. Further, the intermediate partition 130C provided in the flow control damper 101C is arranged at the same position as the intermediate partition 30, but gradually becomes thicker from the leading edge and the trailing edge toward the central portion, with the central portion as a boundary. The leading edge side and the trailing edge side have a symmetrical cross-sectional shape. Further, the middle partition 130D included in the flow control damper 101D is arranged at the same position as the middle partition 30, but gradually becomes thicker from the leading edge and the trailing edge toward the center, and is the same as the middle partition 30. It has a cross-sectional shape, but the front and back are reversed so that it gradually becomes thicker from the leading edge side to the trailing edge side.

When the flow control dampers 101A, 101B, 101C, and 101D related to such a comparative example were analyzed, the static pressure detected in each of the comparative examples was unstable. From this analysis result, the cross-sectional shape of the leading edge of the blades 23a and 23b is sharpened so that the fluid can be easily separated from the movable blades 20a and 20b as in the flow control damper 1 of the present embodiment, and further, from the leading edge side. A partition 30 having a blade-shaped cross section whose thickness gradually decreases toward the trailing edge side is provided between the movable blades 20a and the movable blades 20b, and static pressure is provided through pores 41aF and 41bF provided on the blade surface of the partition 30. It can be seen that if the above is detected, the static pressure can be detected more stably than the flow control dampers 101A, 101B, 101C, and 101D according to the comparative example. That is, as in the flow control damper 1 according to the present embodiment, the leading edge of the blade portion has a cross-sectional shape that is easy to peel off, the partition has a blade shape, and the pressure is detected on the downstream side thereof, thereby stabilizing the condition. It can be seen that the pressure can be detected. However, the flow rate control dampers 101A, 101B, 101C, and 101D according to these comparative examples can detect pressure more stably than the flow rate control dampers without at least a partition.

In addition, since the position of the hole for pressure measurement was verified, the verification result will be described below. FIG. 16 is a diagram showing the position of the pressure measuring port. In this verification, the suitability of the position of the pressure measurement port for detecting the downstream pressure (static pressure) of the differential pressure type flow meter is verified, and the following three points are targeted for verification. That is, when the pressure measuring ports are provided symmetrically on the inner wall surface of the casing 10 on the downstream side of the partition 30 as shown by the reference numeral A in FIG. 16 (A) (hereinafter, referred to as “pattern A”). As indicated by reference numeral C1 in FIG. 16B, the pressure measuring port is provided on the inclined surfaces 31Ra and 31Rb of the upper and lower wing surfaces of the partition 30 in which the thickness gradually decreases from the upstream side to the downstream side. When provided (corresponding to the pores 33aR and 33bR of the above embodiment, hereinafter referred to as "pattern C1"), the pressure measuring port is located on the upper side and the lower side of the partition 30 as shown by the reference numeral C2 in FIG. 16 (B). When provided on the thickest portion of both wing surfaces of the above (hereinafter referred to as "pattern C2"), there are three locations. Then, in this verification, in addition to the three patterns A, C1 and C2, pressure measuring ports are provided in both the reference numerals C1 and the reference numeral C2 in FIG. 16B, and the average value thereof is taken (hereinafter, "" (Pattern C3) was also verified. As for the pattern A, a cover that opens toward the downstream side is attached so as to cover the pressure measurement port on the inner wall surface so as not to pick up the dynamic pressure as much as possible.

FIG. 17 is a graph showing the verification results. Further, FIG. 18 is a diagram showing a pattern of drift in the present verification. The "straight pipe" in the graph of FIG. 17 is data when the duct on the upstream side of the flow control damper is straight and there is no drift. Further, "horizontal elbow axis" in the graph of FIG. 17 means that there is an elbow that bends to the right or left on the upstream side of the flow control damper, and when viewed along the horizontal direction as shown in the left figure of FIG. It is the data when the drift is generated in. Further, "vertical elbow axis" in the graph of FIG. 17 means that there is an elbow that bends upward or downward on the upstream side of the flow control damper, and when viewed along the vertical direction as shown in the right figure of FIG. It is the data when the drift is generated in. Each data is data when pressure detection is performed 100 times. Each data shows its mean value at the position of the circle and its standard deviation of 2 sigma by the length of the arm extending from the circle. In each pattern, the position of the circle means the difference in the pressure detection value between the straight pipe and the elbow condition (the smaller the difference is better), and the standard deviation means the variation in the detected pressure (the smaller the better). The measurement was performed under the conditions that the back pressure between the air supply fan provided on the upstream side of the flow rate damper and the flow rate damper was 400 Pa and the control wind speed was 2 m / s.

As can be seen from the graph of FIG. 17, it can be seen that the detected pressures of the patterns C2 and C3 are different from those of the patterns A and C1 depending on the state of the air flow. Therefore, it can be seen that pattern A or pattern C1 is desirable in order to suppress the influence of the detected pressure due to the shape of the duct on the upstream side of the flow control damper. In view of the fact that the pattern A is provided with a cover for preventing the dynamic pressure from being picked up, the pattern C1 which does not require a cover and can utilize the hollow partition 30 as a header for pressure equalization. Is structurally more advantageous than pattern A. That is, the pressure detection port has an inclined surface 31Ra, which gradually becomes thinner from the upstream side to the downstream side of both the upper and lower wing surfaces of the partition 30 like the pores 33aR and 33bR of the above embodiment. It turns out that it is advantageous to provide it in the portion of 31Rb.

As another pattern that can be considered as a verification target, for example, a large number of pressure detection ports such as pattern A are provided on the inner wall surface of the casing 10, and a header or the like for equalizing the pressure from each pressure detection port is provided. However, there are structural problems such as pressure loss due to the installation of a cover covering each pressure detection port, interference with the drive device 60 on the outer surface of the casing 10, and an increase in manufacturing cost. Therefore, it is rational to provide the pressure detection port on the blade surface of the partition 30 like the pores 33aR and 33bR of the above embodiment.

1,101A, 101B, 101C, 101D ... Flow control damper: 10 ... Casing: 11F, 11R ... Opening: 12F, 12R ... Flange: 13 ... Mounting holes: 20a, 20b, 120a, 120b ... Movable blades: 21a, 21b ... Rotation axis: 22a, 22b ... Side surface: 23a, 23b ... Blades: 24a, 24b ... Flat surface: 25a, 25b ... Curved surface: 30, 130A, 130B, 130C, 130D ... Partition: 31 ... Airfoil: 31Fa, 31Fb ... Increasing surface: 31Ra, 31Rb ... Inclined surface: 32 ... Slat: 33aR, 33bR, 41aF, 41bF ... Pore: 34 ... Plate material: 35 ... Gasket: 36, 42aF, 42bF ... Tube connection port: 36t, 42t ... Tube: 40a, 40b ... Pressure detector tube: 50aF, 50aR, 50bF, 50bR ... Guide member: 51aF, 51bF ...・ Gasket: 60 ・ ・ Drive device: 61 ・ ・ Stepping motor: 62a, 62b ・ ・ Gear: 70 ・ ・ Controller: 71 ・ ・ Slight differential pressure sensor

Claims (8)

A casing that is connected to a duct to form a fluid flow path,
A pair of movable blades that control the flow rate by increasing or decreasing the distance between them in the casing, and have a sharp cross-sectional shape at the leading edge.
A pipe arranged so as to cross the flow path on the upstream side of the pair of movable blades, and a pressure detection pipe having a first pressure measurement hole used for pressure measurement of a differential pressure type flow meter on the outer peripheral surface. When,
A plate-shaped member that divides the flow path between the pair of movable blades into one movable blade side and the other movable blade side, and is a second pressure measurement used for pressure measurement of the differential pressure type flow meter. A flow control damper with a partition having a hole for the blade surface. The first pressure measuring hole opens in the upstream direction of the flow path.
The flow rate control damper according to claim 1. The pressure detector tube has a plurality of holes for the first pressure measurement.
The flow rate control damper according to claim 1 or 2. The pressure detector tube is arranged on each upstream side of the two flow paths between the pair of movable blades partitioned by the partition.
The flow rate control damper according to any one of claims 1 to 3. The partition is a plate-shaped member formed of a hollow member.
The second pressure measuring hole is formed so as to communicate with the inside and outside of the partition.
The flow rate control damper according to any one of claims 1 to 4. The partition has an airfoil portion whose thickness gradually decreases from the upstream side to the downstream side and whose cross-sectional shape is an airfoil shape.
The flow rate control damper according to any one of claims 1 to 5. The second pressure measuring hole is formed on an inclined surface whose thickness gradually decreases from the upstream side to the downstream side.
The flow rate control damper according to claim 6. The partition has a slat portion formed so as to protrude upstream from the leading edge of the airfoil portion.
The flow control damper according to claim 6 or 7.

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