JPH0126010B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for sensing the pressure (total pressure and static pressure) of a fluid flowing in a conduit.

Pitot tubes are used to measure the pressure of fluid in pipes, but in the case of blower performance tests, the pipe cross-sectional area is divided into multiple equal parts, and the measured value at each division point of the pitot pipe is measured. The average pressure is calculated by taking the arithmetic mean of (Pitot tube equal area cross section method, JIS B8330).
Although this method is suitable for cases where accuracy is required, such as in blower performance tests, there are various problems in actual operating sites, such as in air conditioner rooms. In other words, the above method requires rectifying straight pipes approximately 10 times the diameter of the pipe at the front and rear of the measurement position, but such space cannot be taken in actual operation sites such as air conditioning equipment rooms, and the flow It is difficult to determine the angle and position of the pitot tube, and errors due to human factors are likely to occur. Further, the pressure distribution of the fluid with respect to the cross-sectional area changes from time to time, and there are problems such as the true average value cannot be measured unless measurements are made at each point simultaneously.

To solve this problem, a cylindrical rectifier tube with an opening in the flow direction of the pipe fluid is fixed at each measurement point divided by the Pitot tube equal area cross section method, and the rectifier tube has an opening in the fluid flow direction. A total pressure sensing part that senses total pressure and a static pressure sensing part that senses static pressure are provided at the downstream end, and the total pressure sensing parts of each rectifier tube are connected through a total pressure manifold, and the static pressure sensing part are connected by a static pressure manifold, and capillary tubes are installed inside these manifolds.To average the total pressure and static pressure, respectively, the total pressure is measured from the total pressure manifold, and the static pressure is measured from the static pressure manifold. There is a device designed to do this. However, this device has a complicated structure in which each manifold is a double tube, and the rectifier tube must be made longer to reduce measurement errors, which increases the overall length of the device. Ta.

In view of the above points, it is an object of the present invention to provide a fluid pressure sensing device that has a simple structure, shortens the length of the device, and reduces measurement errors.

For this purpose, the device of the present invention includes a partition member that divides the inside of a hollow body that is flattened in a direction perpendicular to the flow direction of the fluid in the pipe line into two chambers, an upstream side and a downstream side of the hollow body. Fixed in the direction perpendicular to the direction, said 2
A plurality of total pressure measurement holes are bored in the upstream end face of the hollow body having a chamber in the flow direction, and the upstream chamber of the hollow body is opened by the total pressure measurement holes, and the hollow body has a chamber in the flow direction. A plurality of static pressure measurement holes are bored in at least one of the parallel surfaces in a direction perpendicular to the flow direction, a chamber on the downstream side of the hollow body is opened by the static pressure measurement holes, and the static pressure A protruding member for assisting static pressure measurement is appropriately protruded outside the hollow body on the downstream side of the measurement hole in a direction perpendicular to the flow direction, and the total pressure is transferred from the chamber on the upstream side of the hollow body to the downstream side. This device is characterized in that static pressure is measured from the chamber.

The details of the present invention will be explained below based on the illustrated embodiments.

Fig. 1 shows an embodiment of the hollow body that is the basis of the device of the present invention, and Fig. 2 shows a perspective view of the fluid pressure sensing device 10 of the present invention, where the direction of arrow A is the flow direction of the fluid. be.

As shown in FIG. 1, the basic body of the device of the present invention is
A hollow body that is flattened in a direction perpendicular to the flow direction, and a partition member 1 fixed inside in a direction perpendicular to the flow direction, which separates an upstream chamber, i.e., a total pressure averaging chamber 2, and a downstream chamber, i.e., a static pressure averaging chamber. It is divided into two chambers. A plurality of total pressure measurement holes 4, 4, . . . are formed in the upstream end face in the flow direction, and the respective total pressure measurement holes 4, 4, . Therefore, the total pressures measured by the total pressure measurement holes 4, 4, . . . are averaged in the total pressure averaging chamber 2. Further, as shown in the cross-sectional view of FIG. 5, it is preferable that the upstream end face in which the total pressure measurement holes 4, 4, . . . are formed be formed into an arc shape.

In the figure, reference numerals 5, 5, . . . indicate static pressure measuring holes, which are bored in a plane parallel to the flow direction, and the static pressure measuring holes 5, 5, . . . communicate with each other via the static pressure averaging chamber 3. Therefore,
The static pressures measured by the static pressure measurement holes 5, 5, . . . are averaged in the static pressure averaging chamber 3. Further, in the illustrated embodiment, the grooves are formed on both sides of the plane parallel to the flow direction, but they may be formed only on one side.

In addition, 6 and 7 in the figure indicate the total pressure that connects the pipes for guiding the average total pressure averaged in the total pressure averaging chamber 2 and the average static pressure averaged in the static pressure averaging chamber 3 to a measuring device such as a manometer, respectively. These are the outlet and the static pressure outlet. The outlet ports 6 and 7 may be threaded with female threads or provided with nipples for convenience when connecting pipes. Further, in this embodiment, the outlet is provided so that the pressure can be taken out from either side, but the outlet may be provided on either side.

The fluid pressure sensing device 10 of the present invention shown in FIG.
Similar to the one shown in Fig. 1, the interior of a hollow body that is flattened in a direction perpendicular to the flow direction is divided into two chambers, an upstream chamber and a downstream chamber, by a partition member 1, and the upstream side has a total pressure. There is an averaging chamber 2, and the downstream side is a static pressure averaging chamber 3.
A total pressure measuring hole 4 is formed in the total pressure averaging chamber 2, and a static pressure measuring hole 5 is formed in the static pressure averaging chamber 3. Also, 6 and 7 in the figure
are the total pressure outlet and the static pressure outlet, respectively. Reference numeral 8 in the figure denotes a protruding member for assisting static pressure measurement, which is protruded at an appropriate position on the downstream side of the static pressure measurement hole 5 on the outer surface of the hollow member. It is preferable that the static pressure measurement assisting protruding member 8 is continuous as shown in the figure, but it may also be provided separately for each static pressure measurement hole 5, or it may be a triangular piece as shown in the figure. It doesn't have to be a shaped thing.

In addition, in FIGS. 4 and 5, the length of the fluid pressure sensing device in the direction perpendicular to the fluid flow direction is L, the length in the flow direction is M, the thickness is d, and the static pressure measurement hole is measured from the leading edge. 5 is represented by N, and the distance from the static pressure measurement hole 5 to the static pressure measurement auxiliary protruding member 8 is represented by Q. The pitch of the total pressure measurement hole 4 and the static pressure measurement hole 5 is indicated by a subscript. It is represented by P, and P ₁ and
P ₇ is the distance from the nearest side edge surface, P ₂ , P ₃ ,
P ₄ , P ₅ and P ₆ are distances to adjacent measurement holes.

The state of use of the apparatus of the present invention having the above configuration will be explained below.

FIG. 6 shows fluid pressure sensing devices 10, 10, . . . of the present invention.
The number of devices required varies depending on the diameter of the pipe or the required precision of the measured pressure. Also, the fluid is at arrow B
The direction is the flow direction.

Fluid pressure sensing devices 10, 10... are installed in the pipe so that the total pressure measurement hole 4 faces upstream in the flow direction, and are installed outside the pipe to detect the total pressure collecting pipe 11 and the static pressure collecting pipe 12.
The total pressure averaging chamber 2 and the static pressure averaging chamber 3 of each fluid pressure sensing device 10, 10, . . . are communicated with each other. Therefore, the total pressure averaging chambers 2 and static pressure averaging chambers 3 of each fluid pressure sensing device 10, 10, . . . communicate with each other through the total pressure collecting pipe 11 or the static pressure collecting pipe 12. And a total pressure collecting pipe 11 and a static pressure collecting pipe 12
If it is connected to a measuring device 13 such as a manometer, the average total pressure and the average static pressure can be determined, and it goes without saying that the average dynamic pressure can also be determined. Further, in FIG. 6, the total pressure manifold 11 and the static pressure manifold 12 are provided on the side surface shown in the foreground, but the total pressure manifold 11 and the static pressure manifold pipe 12 are also provided on the opposite side.
2, and the total pressure and static pressure can be averaged by collecting pipes provided on both sides.

In the figure, reference numeral 14 denotes a damper that adjusts the flow rate by changing the opening degree of the pipe line and is provided downstream of the fluid pressure sensing devices 10, 10, . . . . The damper 14 changes the opening degree by changing the angle of the damper blade 15 with respect to the pipe by turning a handle 17 provided outside the pipe.
In this case, if the measuring device 13 is a flow meter, the flow rate can be adjusted while checking the flow meter, and it is also possible to automatically control the flow rate using the measured pressure as a signal. In the figure, numeral 18 is a rectifier installed upstream of the fluid pressure sensing device using a wire mesh or the like. In the figure, R indicates the distance from the front edge of the fluid pressure sensing device 10 to the damper shaft 16 of the damper 14.

Furthermore, although FIG. 6 shows a case in which the tube is installed in a rectangular conduit, when it is installed in a circular conduit, it may be installed radially from the center.

As mentioned above, in actual operation sites such as air conditioner rooms, straight rectifier pipes may not be available, and the diameters of the pipes may vary. Therefore, a test was conducted to determine whether the device of the present invention could be put to practical use, assuming an actual driving site, and the test results will be described below.

First, we performed the following tests on a pipe with a pipe diameter of □300 x 200 mm and examined the results.

(1) How the optimal length of the fluid pressure sensing device 10 in the fluid flow direction in the pipeline and the protruding position of the static pressure measurement auxiliary protruding member 8 affect static pressure measurement. , static pressure was measured and studied by changing the average wind speed. The external dimensions of the fluid pressure sensing device 10 subjected to the test correspond to the symbols in FIGS. 4 and 5, and are as follows.

L = 280 mm M = 254 mm d = 10 mm P ₁ = P ₇ = 40 mm P ₂ = P ₆ = 100 mm P ₃ = P ₄ = P ₅ = 0 mm (none) Diameter of static pressure measurement hole 5 φ1 mm Also, fluid pressure sensing device The distance N from the front edge of No. 10 to the static pressure measurement hole 5 was a position that was an integral multiple of the thickness d, and measurements were taken at positions from 1d to 25d. 25d from the leading edge of the fluid pressure sensing device 10
The protruding member 8 for static pressure measurement assistance was provided protrudingly at a distance of 20d from the test piece, and tests were conducted on each protruding position. The protruding height of the static pressure measurement auxiliary protruding member 8 was approximately 2 mm. In addition, a straight pipe portion was appropriately selected for the pipe, and an 8-mesh wire mesh was used as a rectifier 18 upstream of the fluid pressure sensing device 10. The results are shown in FIGS. 7 to 9. The figure shows the measured value at the static pressure measurement hole 5 at position 1d, normalized to -1.0mmAq/mmAq, and in each figure, 〇, ○†

Claims (1)

[Claims] 1 A partition member is fixed in a direction perpendicular to the flow direction inside a hollow body that is flattened in a direction perpendicular to the flow direction of the fluid in the pipe line, dividing the hollow body into two chambers on the upstream side and the downstream side. , a plurality of total pressure measurement holes are bored in the upstream end face of the hollow body having two chambers in the flow direction, and the upstream chamber of the hollow body is opened by the total pressure measurement holes,
A plurality of static pressure measurement holes are bored in at least one of the planes parallel to the flow direction of the hollow body in a direction perpendicular to the flow direction, and a chamber on the downstream side of the hollow body is opened by the static pressure measurement holes. A protruding member for assisting static pressure measurement is provided in a direction perpendicular to the flow direction and protrudes appropriately from the outside of the hollow body on the downstream side of the static pressure measurement hole. A fluid pressure sensing device that measures total pressure and static pressure from a downstream chamber.