Branch chamber

Abstract

To provide a branch chamber enabling a flow rate from an outflow port to become uniform without requiring an extra space on upper and lower sides and regardless of small pressure loss.SOLUTION: Within a chamber body of a branch chamber, when a surface in parallel with an inner surface of a tip wall part 24 is defined as an orthogonal surface, flow rate uniformizing means 40 for making a flow rate of air flowing on the orthogonal surface uniform is disposed before an outflow port formed at a position nearest to an inflow port 30, and guide means 50 for changing a moving direction by hitting part of air for guiding to the outflow port is disposed between the plurality of outflow ports 32A, etc.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a branch chamber for air conditioning.

Background Art

[0002] In a whole-building air conditioning system or the like, generally, a main duct extends from an air conditioner installed in a building, and conditioned air is supplied to each air conditioning area such as a living room through a branch duct connected to the main duct. A branch chamber is provided between the main duct and a plurality of branch ducts. This type of branch chamber is typically configured in a rectangular parallelepiped hollow box shape. In a branch chamber having such a configuration, an inlet for conditioned air is formed at one end side in the length direction, and a plurality of outlets are formed at the other end side. The flow rate is smaller at the outlet closer to the inlet and tends to be larger at the outlet farther from the inlet. The difference in the flow rate of the air flowing out from the outlets is maintained in the branch ducts and is adjusted at the air dampers directly connected to each air conditioning area such as a living room, and the flow rate is equalized. However, the adjustment work at the air dampers requires a lot of time, and moreover, there are also differences in the characteristics of individual air conditioners and variable air volume (VAV) control devices arranged in the previous stage of the branch chamber, so even more time is required for such adjustment work. In this regard, it is ideal if the flow rate from each outlet of the branch chamber is uniform, because the time required for the adjustment work at the air dampers is reduced.

[0003] On the other hand, a technique has been proposed in which the branch chamber is configured in a flat box shape with a height smaller than the width, an inlet is formed in one wall in the height direction (thickness direction) (for example, the wall constituting the bottom surface), and the air flowing in from the inlet is made to collide with the other wall in the height direction (for example, the wall constituting the ceiling surface) to achieve rectification (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In the technology of the above-mentioned Patent Document 1, since it is necessary to form the inflow port on one wall in the height direction, it is necessary to connect the main duct to the branch chamber from above or below. For this reason, in a place such as the ceiling space where the branch chamber is arranged, a space for piping is required above or below. Further, in the technology of Patent Document 1, until the air flowing into the branch chamber reaches the outlet, the traveling direction changes when the air hits the wall in the height direction, and further, the traveling direction changes again when the air collides with the wall on the back side in the length direction, which is the direction orthogonal to the height direction. Therefore, there is a problem that the pressure loss is large.

[0006] Based on the above, the present invention provides a branch chamber that can equalize the flow rate from the outlet without requiring extra space above and below, and with a small pressure loss.

MEANS FOR SOLVING THE PROBLEMS

[0007] The first invention is a branch chamber having a chamber body in the shape of a hollow box that is long in one direction. The chamber body has a front end wall portion, a rear wall portion, a first side wall portion, a second side wall portion, a bottom wall portion, and a ceiling wall portion. The first side wall portion and the second side wall portion are arranged at opposing positions, and the bottom wall portion and the ceiling wall portion are arranged at opposing positions. A peripheral wall portion is formed by the first side wall portion, the second side wall portion, the bottom wall portion, and the ceiling wall portion. The front end wall portion is arranged to close the front end portion of the peripheral wall portion, and the rear wall portion is arranged to close the rear end portion of the peripheral wall portion. An inlet for air to flow into the chamber body is connected to the front end wall portion. A plurality of outlets for air to flow out of the chamber body are connected to the first side wall portion and the second side wall portion at different positions in the longitudinal direction. Inside the chamber body, with the front end wall portion side as the front and the rear wall portion side as the rear, and a plane parallel to the inner surface of the front end wall portion and the inner surface of the rear wall portion as the orthogonal plane, flow rate equalizing means for equalizing the flow rate of air flowing in the orthogonal plane is arranged in front of the outlet closest to the inlet. Between the plurality of outlets connected to each of the first side wall portion and the second side wall portion, guide means is arranged so that a part of the air that has passed through the flow rate equalizing means hits and changes its traveling direction and is guided to the outlet. This is the branch chamber.

[0008] According to the configuration of the first invention, since the inlet is connected to the front end wall portion and the outlets are connected to the first side wall portion and the second side wall portion, there is no need for extra space for piping above and below the branch chamber.

[0009] Incidentally, the air flow rate is not always the same in each part of the opening surface (orthogonal surface) of the inlet, and there may be a bias in the flow rate. For example, generally, the flow rate at the center of the opening surface is larger than that of other parts. However, there may also be cases where the flow rate of the upper part of the opening surface is larger than that of other parts, or where the left or right part of the opening surface has a larger flow rate than other parts. The bias in the flow rate at the inlet continues inside the chamber body and becomes a factor for the difference in the air flow rate flowing out from the plurality of outlets. In this regard, according to the configuration of the first invention, the flow rate of the air flowing on the orthogonal surface is equalized by the flow rate equalizing means. As a result, since the air passes near the first side wall portion and the second side wall portion, it becomes particularly easy for the air to flow into the front outlet.

[0010] Further, when the air passes near the first side wall portion and the second side wall portion, a part of the air surely hits the guide means, changes its traveling direction, and is guided to the outlet located in front of the guide means.

[0011] In this way, the flow rate equalizing means has the effect of promoting the direct inflow of the air in the chamber body into the outlet. Further, the flow rate equalizing means has the effect of enabling the guide means to function effectively. And the air flowing into the outlet located in front of the guide means greatly changes its traveling direction toward the outlet only once when it hits the guide means, and the air flowing into the outlet located behind the guide means greatly changes its traveling direction toward the outlet only once when it hits the back wall portion. Thereby, it is possible to equalize the flow rate from the outlet without requiring an extra space vertically and with a small pressure loss.

[0012] The second invention is a branch chamber in which, in the configuration of the first invention, the flow rate equalizing means is a net-like member having an opening ratio of 50% or more.

[0013] According to the configuration of the second invention, since the flow rate equalizing means is a net-like member and the opening ratio is 50% or more, it does not cause a large resistance to the air flow.

[0014] The third invention is a branch chamber which, in the configuration of the first invention, is such that the flow rate equalization means is a net-like member having an opening ratio of 60% or more and 95% or less.

[0015] According to the configuration of the third invention, since the flow rate equalization means is a net-like member having an opening ratio of 60% or more and 95% or less, it does not cause a large resistance to the flow of air.

[0016] The fourth invention is a branch chamber which, in the configuration of the first invention, is such that the net-like member is composed of a plurality of openings and a net body that divides the openings, the net body is composed of vertical line portions and horizontal line portions that are orthogonal to each other, and the cross section in a direction orthogonal to the longitudinal direction of each of the vertical line portions and the horizontal line portions is formed in a convex shape toward the inlet.

[0017] According to the configuration of the fourth invention, since the cross sections of the vertical line portions and the horizontal line portions are formed in a convex shape toward the inlet, the possibility that the air hitting the net body bounces back in the reverse direction is small. Thereby, the net-like member does not cause a large resistance to the flow of air.

[0018] The fifth invention is a branch chamber which, in the configuration of any one of the first to fourth inventions, is such that the guide means is a plate-like member, and when a line segment connecting the center of the inner surface of the tip wall portion and the center of the inner surface of the back wall portion is taken as the center line, the guide means extends in a direction from the first side wall portion and the second side wall portion toward the center line, and the portion extending in the direction toward the center line in the guide means is formed in an arc shape when viewed from the tip wall portion side, and is configured such that the portion corresponding to the center line protrudes most.

[0019] According to the configuration of the fifth invention, since the guide means is formed in an arc shape when viewed from the tip wall portion side and is configured such that the portion corresponding to the center line protrudes most, it is possible to efficiently guide the air to the outlet located in front of the guide means without excessively disturbing the flow of air.

Advantages of the Invention

[0020] According to the branch chamber of the present invention, without requiring extra space above and below, and despite having a small pressure loss, the flow rate from the outlet can be equalized.

Brief Description of the Drawings

[0021]

Figure 1

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Figure 20

Figure 21

Embodiments for Carrying Out the Invention

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that descriptions of configurations that can be appropriately implemented by those skilled in the art will be omitted, and only the basic configuration of the present invention will be described.

[0023] <First Embodiment> With reference to FIGS. 1 and 2, an outline of the configuration of the branch chamber 1 (hereinafter referred to as "chamber 1") will be described. FIG. 1(a) is a schematic perspective view showing the outer shape of chamber 1. FIG. 1(b) is a schematic perspective view in which the outer part is described by a dotted line to show the internal structure of chamber 1. FIG. 2(a) is a schematic perspective view showing the outer shape of the chamber body 20 (hereinafter referred to as "body 20"). FIG. 2(b) is a schematic perspective view in which the outer part is described by a dotted line to show the internal structure of body 20.

[0024] <Configuration of the Chamber Body> As shown in FIGS. 2(a) and 2(b), the body 20 is configured in a hollow box shape that is long in one direction. The body 20 has a front end wall portion 24, a rear wall portion 26, a first side wall portion 22A, a second side wall portion 22C, a bottom wall portion 22B, and a ceiling wall portion 22D. The first side wall portion 22A and the second side wall portion 22C are arranged at opposing positions. The bottom wall portion 22B and the ceiling wall portion 22D are arranged at opposing positions. The front end wall portion 24 and the rear wall portion 26 are arranged at opposing positions.

[0025] In this specification, in the direction connecting the front end wall portion 24 and the rear wall portion 26 (hereinafter referred to as the "longitudinal direction"), the front end wall portion 24 side is taken as the front, and the rear wall portion 26 side is taken as the rear. And the foremost part is called the front end portion, and the rearmost part is called the rear end portion. Also, the front end wall portion 24 side is taken as the front surface, and the rear wall portion 26 side is taken as the back surface. As shown in FIGS. 2(a) and 2(b), the main body 20 is formed in a rectangular parallelepiped shape that is long in the longitudinal direction.

[0026] As shown in FIGS. 2(a) and 2(b), the peripheral wall portion 22 is constituted by the first side wall portion 22A, the second side wall portion 22C, the bottom wall portion 22B, and the ceiling wall portion 22D. The front end wall portion 24 is disposed so as to close the front end portion of the peripheral wall portion 22. The rear wall portion 26 is disposed so as to close the rear end portion of the peripheral wall portion 22.

[0027] As shown in FIGS. 2(a) and 2(b), an inlet 30 for air to flow into the main body 20 is connected to the center of the front end wall portion 24. The air flowing into the main body 20 through the inlet 30 is, for example, air whose temperature and humidity have been adjusted by an air conditioner.

[0028] A plurality of outlets 32A, etc. are formed at different positions in the longitudinal direction on the first side wall portion 22A and the second side wall portion 22C, respectively. The outlets 32A and 32C are connected to the first side wall portion 22A, and the outlets 32B and 32D are connected to the second side wall portion 22C. Air flows out of the main body 20 from the outlets 32A to 32D. The outlets 32A to 32D are cylindrical members having the same diameter (inner diameter).

[0029] Note that an opening having a diameter substantially the same as the outer diameter of the inlet 30 is formed in the front end wall portion 24, and it is configured so that the inlet 30 can be fitted. Similarly, openings having a diameter substantially the same as the outer diameter of the outlets 32A to 32D are formed in the first side wall portion 22A and the second side wall portion 22C.

[0030] As shown in Fig. 2(b), conceive a line segment SL connecting the center of the tip wall portion 24 and the center of the rear wall portion 26 in the front view, conceive a plane orthogonal to the line segment SL, and set that plane as the orthogonal plane. That is, the orthogonal plane is a plane orthogonal to the longitudinal direction. In other words, the orthogonal plane is a plane parallel to the inner surfaces of the tip wall portion 24 and the rear wall portion 26. The orthogonal plane can be conceived at any position in the longitudinal direction of the main body 20.

[0031] As shown in Figs. 2(a) and 2(b), a net-like member 40 is disposed in front in the longitudinal direction of the outlet ports 32A and 32B formed at the position closest to the inlet port 30. The net-like member 40 is a member for equalizing the flow rate of air flowing in the orthogonal plane and is an example of a flow rate equalizing means. Note that "equalization" does not mean making the flow rate of air completely identical at all parts of the orthogonal plane. It means that the state after passing through the net-like member 40 is closer to having the same flow rate in the orthogonal plane than the state before passing through the net-like member 40.

[0032] Inside the main body 20, a guide member 50A is disposed on the first side wall portion 22A, and a guide member 50B is disposed on the second side wall portion 22C. The guide member 50A is disposed between the outlet ports 32A and 32C, and the guide member 50B is disposed between the outlet ports 32B and 32D. The guide members 50A and 50B are configured such that a part of the air passing through the net-like member 40 hits them, causing the traveling direction to be changed and being guided to the outlet ports 32A and 32B.

[0033] <Appearance configuration of the branch chamber> As shown in Figs. 1(a) and (b), a part of the main body 20 is covered with an outer frame 10 formed of a metal plate. Specifically, the tip wall portion 24, the rear wall portion 26, the first side wall portion 22A, and the second side wall portion 22C are covered with the outer frame 10. Most of the bottom wall portion 22B and the ceiling wall portion 22D are not covered with the outer frame 10 and are exposed.

[0034] The outer frame 10 is formed with an opening having a diameter substantially the same as the outer diameter of the inlet at a position corresponding to the inlet 30, and is configured to be able to fit the inlet 30. Similarly, the outer frame 10 is formed with openings having a diameter substantially the same as the outer diameter of the outlets 32A to 32D at positions corresponding to the outlets 32A to 32D.

[0035] The cylindrical inlet 30 is fitted to the main body 20 and the outer frame 10 in a manner passing through the openings of the main body 20 and the outer frame 10. Also, the cylindrical outlets 32A to 32D are fitted to the main body 20 and the outer frame 10 in a manner passing through the openings of the main body 20 and the outer frame 10.

[0036] <Air flow and dimensions in chamber 1> FIG. 3(a) is a schematic plan view of chamber 1, FIG. 3(b) is a schematic side view of chamber 1, and FIG. 3(c) is a schematic front view of chamber 1. As shown in FIG. 3(a), the air sent from the direction of arrow X1 flows into chamber 1 from the inlet 30, and flows out through the outlets 32A to 32D into the ducts 80A to 80D respectively connected to the outlets 32A to 32D. The amounts of air flowing out into the ducts 80A to 80D are substantially the same as shown by the arrows Y1A to Y1D. In this specification, the meaning of being substantially the same means that the deviation from the reference flow rate is within 10% (percent). The ducts 80A to 80D are, for example, sound-absorbing flexible ducts.

[0037] Referring to FIG. 4, the relative dimensions of each part of chamber 1 will be described. FIG. 4(a) is a schematic plan view seen through the inside of chamber 1. FIG. 4(b) is a schematic side view of chamber 1. FIG. 4(c) is a schematic front view of chamber 1.

[0038] As shown in FIGS. 4(a) and 4(c), the inner width of the outer frame 10 is width W1, while the width of the internal space of the main body 20 is width W2, and width W2 is smaller than width W1 by the thickness w22 (see FIG. 5(a)) of the microduct plates on both side surfaces constituting the main body 20. The thickness w22 is 25 millimeters (mm). Therefore, the thickness of the microduct plates on both side surfaces is 50 millimeters (mm). For this reason, width W1 is 400 millimeters (mm), and W2 is 350 millimeters (mm).

[0039] The diameter (inner diameter) of the inlet 30 is diameter d30, and the diameters (inner diameters) of the outlets 32A to 32D are diameter d32. Diameter d32 is smaller than diameter d30. Diameter d30 is 250 millimeters (mm), and diameter d32 is 175 millimeters (mm).

[0040] The width of the space between the guide members 50A and 50B is width W3. Width W3 is defined by the extent to which the guide members 50A and 50B extend toward the center line SL (hereinafter referred to as the "extension width"). The extension widths of the guide members 50A and 50B are defined as the length at which the air flowing in from the inlet 30 can flow out from the outlets 32A to 32D at a uniform flow rate in the configuration of the chamber 1. The extension width is width W8. The ratio of twice the extension width W8 to the width W2 of the internal space of the main body 20 (W8×2 / W2; hereinafter referred to as the "extension ratio") is in the range of 0.30 or more and 0.60 or less, preferably in the range of 0.35 or more and 0.50, and more preferably in the range of 0.40 or more and 0.50 or less. In the present embodiment, W8 is 80 millimeters (mm), and as described above, W2 is 350 millimeters (mm), so the extension ratio is approximately 0.46. And in the present embodiment, width W3 is 190 millimeters (mm).

[0041] As shown in FIG. 4(b), the height of the inner shape of the chamber 1 is H1, while the height of the internal space of the main body 20 is H2, and H2 is smaller than H1 by the thickness w22 (see FIG. 5(a)) of the microduct plates on the ceiling surface and the bottom surface constituting the main body 20. For this reason, H1 is 350 millimeters (mm), and H2 is 300 millimeters (mm).

[0042] The length of the inner shape of the chamber 1 is L1, while the length of the internal space of the main body 20 is L2, and L2 is smaller than L1 by the thickness w22 (see FIG. 5(a)) of the microduct plates on the front end portion and the rear end portion constituting the main body 20. For this reason, L1 is 750 millimeters (mm), and L2 is 700 millimeters (mm).

[0043] The width W1 is larger than the height H1. And the length L1 is larger than the width W1. For this reason, the general outer shape of the chamber 1 is a flat rectangular parallelepiped shape that is long in the direction of the line segment SL. Similarly, the width W2 is larger than the height H2. The length L2 is larger than the width W2. For this reason, the general outer shape of the main body 20 is a flat rectangular parallelepiped shape that is long in the direction of the line segment SL.

[0044] <Regarding each member> Next, each member constituting the chamber 1 will be described. FIGS. 5, 6, 7, 8, and 9 are diagrams showing the main members constituting the chamber 1.

[0045] FIG. 5 is a diagram showing a member formed by processing a microduct plate. The microduct plate is also called a glass board plate, and is a material in which glass fibers are hardened with a thermosetting resin and the outer portion is finished with an aluminum foil reinforced with glass yarn. The microduct plate is excellent in heat insulation and sound absorption, and can quietly carry air without greatly changing the temperature of the air. Also, the microduct plate is lightweight and is very lightweight compared to the iron plates generally used for ducts. The microduct plate of the present embodiment is about 64 kilograms per cubic meter (kg / m 3) That is. If the member formed by processing the microduct plate in this embodiment is made of a metal steel plate, the weight increases by about 35% (percent).

[0046] FIG. 5(a) shows a state where the peripheral wall portion 22 is unfolded. The peripheral wall portion 22 in the state shown in FIG. 5(a) is folded to become the peripheral wall portion 22 constituting the main body 20.

[0047] As shown in FIG. 5(a), the microduct plate is a plate-like member having a thickness w22. In this embodiment, the thickness w22 is 25 millimeters (mm). The microduct plate forms a peripheral wall portion 22 composed of a first side wall portion 22A, a second side wall portion 22C, a bottom wall portion 22B, and a ceiling wall portion 22D. Openings 22a and 22c having substantially the same diameter as the outer diameters of the outlets 32A and 32C are formed at different positions in the longitudinal direction (the direction indicated by the arrow X10) on the first side wall portion 22A.

[0048] Openings 22b and 22d having substantially the same diameter as the outer diameters of the outlets 32B and 32D are formed at different positions in the longitudinal direction on the second side wall portion 22C. In the longitudinal direction positions, the opening 22a and the opening 22b are formed at substantially the same position, and the opening 22c and the opening 22d are formed at substantially the same position. Grooves b1 and b2 for fixing the mesh member 40, and grooves c1 and c2 for fixing the guide members 50A and 50B are formed on the first side wall portion 22A and the second side wall portion 22C. A triangular groove a1 having a triangular cross-section for folding in the direction of the arrow Z1 is formed between the first side wall portion 22A and the bottom wall portion 22B. A triangular groove a2 for folding in the direction of the arrow Z2 is formed between the bottom wall portion 22B and the second side wall portion 22C, and a triangular groove a3 for folding in the direction of the arrow Z3 is formed between the second side wall portion 22C and the ceiling wall portion 22D.

[0049] FIG. 5(b) is a view showing the front end wall portion 24 and the back wall portion 26. The front end wall portion 24 and the back wall portion 26 are also formed by processing the microduct plate. The front end wall portion 24 is configured with an opening 24b formed in the main body portion 24a. The diameter of the opening 24b is substantially the same as the outer diameter of the inlet 30.

[0050] FIG. 5(c) is a view showing the guide portions 50A and 50B. The guide portions 50A and 50B are collectively referred to as the "guide portion 50". The guide portion 50 is also formed by processing a microduct plate.

[0051] FIG. 6 is a schematic view showing the respective members constituting the outer frame 10. The outer frame 10 is formed by processing a metal plate. The metal plate is, for example, a galvanized steel plate having a thickness of 0.6 millimeters (mm).

[0052] FIG. 6(a) is a schematic perspective view showing the first side frame 10a and the second side frame 10b. The first side frame 10a is a member for covering the first side wall portion 22A, and the second side frame 10b is a member for covering the second side wall portion 22C. As shown in FIG. 6(a), the first side frame 10a and the second side frame 10b each have an outer surface 12a and an inner surface 12b, and the upper end portion and the lower end portion are bent inward.

[0053] Openings 14a and 14c are formed at different positions in the longitudinal direction (the direction indicated by the arrow X10) in the first side frame 10a. The opening 14a is formed at a position and in a shape corresponding to the opening 22a of the first side wall portion 22A, and the opening 14c is formed at a position and in a shape corresponding to the opening 22c. Openings 14b and 14d are formed at different positions in the longitudinal direction in the second side frame 10b. The opening 14b is formed at a position and in a shape corresponding to the opening 22b of the second side wall portion 22C, and the opening 14d is formed at a position and in a shape corresponding to the opening 22d.

[0054] FIG. 6(b) is a schematic perspective view showing the front end frame 10c and the rear frame 10d. The front end frame 10c is a member for covering the front end wall portion 24, and the rear frame 10d is a member for covering the rear wall portion 26. As shown in FIG. 6(b), the front end frame 10c is configured such that an opening 16b is formed in the main body portion 16a. The opening 16b of the front end frame 10c is formed at a position and in a shape corresponding to the opening 24b of the front end wall portion 24. The rear frame 10d is composed of the main body portion 18, and no opening is formed in the main body portion 18.

[0055] FIG. 7(a) is a schematic perspective view showing the inlet 30, FIG. 7(b) is a schematic perspective view showing the outlets 32A to 32D, and FIG. 7(c) is a schematic perspective view showing the mesh member 40.

[0056] The inlet 30 and the outlets 32A to 32D are formed by processing a metal plate. The metal plate is, for example, a galvanized steel plate with a thickness of 0.6 millimeters (mm). The inlet 30 is composed of a cylindrical portion 30a and a flange portion 30b. The outlets 32A to 32D are composed of a cylindrical portion 32a and a flange portion 32b.

[0057] <<Regarding the mesh member>> The mesh member 40 is composed of a frame portion 40a and a mesh portion 40b. The mesh member 40 will be described in detail below with reference to FIGS. 8 and 9.

[0058] As shown in FIGS. 8(a) to 8(c), the mesh member 40 is configured by fixing the mesh portion 40b to the frame portion 40a. FIG. 8(a) shows the mesh member 40 in a front view, and FIG. 8(b) shows the frame portion 40a and the mesh portion 40b in a front view. FIG. 8(c) is a plan view of the mesh member 40 of FIG. 8(a) viewed from the direction of arrow Z11.

[0059] As shown in FIG. 8(b), the frame portion 40a is composed of a frame-shaped member 40a1 with a rectangular opening 40a2 formed in the center. In the frame-shaped member 40a1, the mesh portion 40b is fixed to the inner portion 40a1a along the opening 40a2.

[0060] As shown in FIGS. 8(a) and 8(b), the mesh part 40b is composed of a plurality of openings 40b2 and a mesh body 40b1 that divides the openings 40b2. In the present embodiment, the opening 40b2 is a square opening when viewed from the front. The frame part 40a is formed by processing a metal plate. The mesh part 40b is formed by punching a metal plate. The metal plate is, for example, a galvanized steel plate with a thickness of 0.6 millimeters (mm). Specifically, a mold with a square cross-section perpendicular to the punching direction and a side length of 20.0 millimeters (mm) is prepared, the mold is mounted on a turret punch press, and the metal plate is punched to form a square opening 40b2. By performing the punching of the metal plate a plurality of times, a plurality of openings 40b2 are formed. The metal plate is punched, and the remaining part becomes the mesh body 40b1.

[0061] As shown in FIG. 8(a), the frame part 40a of the mesh member 40 is a member with a width W4 and a height H3. The mesh part 40b is a member with a width W5 and a height H4. The width W4 is larger than the width W2 of the main body 20 (see FIG. 4(a)) and smaller than the width W1 of the outer frame 10 (same). The height H3 is substantially the same as the height H2 of the main body 20 (see FIG. 4(b)). The width W4 is 370 millimeters (mm), the width W5 is 312 millimeters (mm), the height H3 is 300 millimeters (mm), and the height H4 is 268 millimeters (mm).

[0062] FIG. 9(a) is a conceptual diagram showing an enlarged view of a region 40p1 that is a part of the mesh part 40b in FIG. 8(a). As shown in FIG. 9(a), the mesh body 40b1 is composed of a plurality of horizontal line parts 40b11 and vertical line parts 40b12. The horizontal line part 40b11 and the vertical line part 40b12 are perpendicular to each other. Specifically, the direction in which the horizontal line part 40b11 extends and the direction in which the vertical line part 40b12 extends are perpendicular to each other.

[0063] One surface 40b11s and 40b12s of the plurality of horizontal line portions 40b11 and the plurality of vertical line portions 40b12 is the surface in the direction (front side) where air flows into the chamber 1. In the mesh member 40, the side opposite to the front side is called the back side. Each surface 40b11s and 40b12s is configured to be convex toward the inlet 30. In other words, the cross-section in the direction orthogonal to the longitudinal direction of each horizontal line portion 40b11 and the cross-section in the direction orthogonal to the longitudinal direction of each vertical line portion 40b12 are smaller on the front side than on the back side. Specifically, the most protruding portions of the surfaces 40b11s and 40b12s are flat, but arcs are formed on both sides thereof (see FIG. 10).

[0064] FIG. 9(b) is a schematic view conceptually showing a region 40p1 which is a part of the mesh portion 40b of FIG. 8(a). The width w11 of the mesh body 40b1 is the width in the front view (the state viewed from the direction of the inlet 30) of the horizontal line portion 40b11 and the vertical line portion 40b12, and in the present embodiment, it is 2.5 millimeters (mm). The opening 40b2 is square in the front view, and the length w12 of one side thereof is 20 millimeters (mm). The aperture ratio of the mesh portion 40b is defined in a predetermined range of 50% or more, desirably 60% or more and 95% or less, and more desirably 75% or more and 95% or less. In the present embodiment, the aperture ratio is about 89%. The aperture ratio is the ratio occupied by the opening 40b2 in the entire mesh portion 40b. When the area of one opening 40b2 is s1, the aperture ratio is the ratio occupied by the total area of the area s1 in the entire mesh portion 40b.

[0065] The aperture ratio is basically defined by the ratio of the width w11 of the horizontal line portion 40b11 and the vertical line portion 40b12 constituting the mesh body 40b1 to the width w12 of the opening 40b2. The aperture ratio is substantially the same in each part of the mesh portion 40b. For example, as shown in FIG. 9(b), when the area of the portion including the four openings 40b2 is defined as the area s2, the aperture ratio is the ratio of the four areas s1 to the area s2. That is, as shown in Equation 1 of FIG. 9(b), the aperture ratio (s1×4 / s2) is defined as a value between a predetermined value V1 and V2. And the value V1 is 50. Desirably, the value V1 is 60 and the value V2 is 95. More desirably, V1 is 75 and V2 is 95.

[0066] Next, with reference to FIG. 10, the operation of the mesh portion 40b will be described. FIG. 10 is a conceptual diagram showing the operation of the mesh portion 40b when air flows into the chamber 1 from the suction port 30. In FIG. 10, arrows A1 etc. are vectors indicating the air flow.

[0067] As shown in Fig. 10(a), since the aperture ratio of the mesh portion 40b is as large as about 89%, most of the air passes through the opening portion 40b2 without hitting the mesh main body 40b1. However, a part of the air hits the mesh main body 40b1 and changes its traveling direction as shown by the dotted line. Then, the changed air flow affects the traveling direction of the air that has passed through the opening portion 40b2 without hitting the mesh main body 40b1. Eventually, the traveling directions of most of the air passing through the mesh portion 40b are directly or indirectly affected by the mesh main body 40b1. For example, the air flow A5 passes through the opening portion 40b2 without hitting the mesh main body 40b1, but is affected by the air flow A1 whose traveling direction has been changed by hitting the mesh main body 40b1 and changes its traveling direction. Here, paying attention to the area in the direction orthogonal to the longitudinal direction of the chamber 1 (orthogonal direction), the area of the chamber 1 is larger than the area inside the suction port 30. That is, with respect to the suction port 30, the chamber 1 has a larger space in the direction orthogonal to the longitudinal direction in the orthogonal plane. For this reason, each air molecule constituting the air flow moves in the longitudinal direction vector of the chamber 1 at the suction port 30, but when it enters the inside of the chamber 1, it comes to have a vector component in the orthogonal direction. Furthermore, when the air flow is divided by the mesh main body 40b1, there is a tendency for the air flow in the portion with a large flow rate to be drawn toward the air flow in the portion with a small flow rate. Furthermore, when a part of the air molecules hits the mesh main body 40b1, the air molecules passing through the mesh member 40 are directly or indirectly affected and come to have a larger vector component in the orthogonal direction. As a result, even when the air flows A1 to A8 are not of the same flow rate and are not uniform, when passing through the mesh portion 40b, they spread in the orthogonal direction and are made uniform.

[0068] In reality, the air flowing into chamber 1 from the suction port 30 does not have a uniform flow rate on the orthogonal plane. Generally, as indicated by the difference in the thickness of the arrows in Fig. 10(b), the flow rate in the central part is large. Air molecules that have passed through the mesh member 40 and have a vector component in the orthogonal direction tend to be drawn towards the direction where the flow rate of the air with a relatively low pressure is small. For example, the air flows A12, 13, A16, and A17 in the central part have a relatively large flow rate. In contrast, the air flows A11, A14, A15, and A18 in the peripheral part have a relatively small flow rate. Then, air molecules that have passed through the mesh member 40 and have a vector component in the orthogonal direction tend to be drawn towards the peripheral part. Therefore, even when the air flows A11 to A18 do not have the same flow rate and are not uniform, they are homogenized when passing through the mesh part 40b.

[0069] <<Regarding the guide member>> Next, the guide members 50A and 50B will be described with reference to Fig. 11. As described above, the guide members 50A and 50B are collectively referred to as the "guide member 50". Fig. 11(a) is a front view of the guide member 50, Fig. 11(b) is a plan view of the guide member 50 in Fig. 11(a) viewed from the direction of arrow Z12, and Fig. 11(c) is a side view of the guide member 50 in Fig. 11(a) viewed from the direction of arrow X12. As shown in Figs. 11(a) to 11(c), the guide member 50 is a plate-shaped member with a thickness of 50w1. The thickness 50w1 is the thickness of the microduct plate and is 25 millimeters (mm). The guide member 50 is configured with a height of 50h and a width of W6. The height 50 is 300 millimeters (mm), and the width W6 is 92.5 millimeters (mm).

[0070] Among the width W6, the width of the base part 50a is the width W7, and the width of the extending part 50b is the width W8. The base part 50a is the part fixed to the main body 20, and the extending part 50b is the part extending into the internal space of the main body 20. The outer edge of the extending part 50b is formed in an arc shape, and the central part 50c in the height direction protrudes the most. The width W7 of the base part 50a is 12.5 millimeters (mm), and the width W8 of the extending part 50b is 80.0 millimeters (mm).

[0071] Since the outer edge of the extending portion 50b is formed in an arc shape, it does not excessively impede the flow of air in the longitudinal direction within the main body 20. Also, although it is highly likely that the central portion has the largest flow rate on the orthogonal plane within the main body 20, since the central portion 50c in the height direction of the extending portion 50b protrudes the most, it is possible to change the traveling direction of the air near the central portion on the orthogonal plane within the main body 20 and guide it to the outlet ports 32A and 32B, so that the flow rate can be efficiently equalized.

[0072] <Manufacturing method of the branch chamber> Hereinafter, with reference to FIGS. 12 to 14, the outline of the manufacturing method of the chamber 1 will be described. As shown in FIGS. 12(a) and 12(b), in the state before folding the peripheral wall portion 22 shown in FIG. 5(a), the outlet ports 32A to 32D are inserted into the openings 22a to 22d from the inside. Also, the guide members 50A and 50B are fixed to the first side wall portion 22A and the second side wall portion 22C. Thereafter, the peripheral wall portion 22 is folded to form a cylindrical shape with a rectangular cross-section. In FIG. 12(a), for the sake of convenience of explanation, a state of folding without fixing the guide members 50A and 50B is shown. Actually, as shown in FIG. 12(b), after fixing the outlet ports 32A to 32D and the guide members 50A and 50B to the peripheral wall portion 22, the peripheral wall portion 22 is folded.

[0073] Next, slightly release the folded state of the peripheral wall portion 22, and fix the mesh member 40 at a position in front of the outlet ports 32A and 32B as shown in FIG. 13(a). Subsequently, as shown in FIGS. 13(b) and 13(c), insert and fix the cylindrical portion 30a of the inlet port 30 into the opening 24b of the tip wall portion 24. With the flange portion 30b in contact with the back surface of the main body portion 24a, the inlet port 30 is fixed to the tip wall portion 24. Next, as shown in FIG. 14(a), fix the tip wall portion 24 to which the inlet port 30 is fixed to the front end portion of the peripheral wall portion 22. Also, fix the rear wall portion 26 to the rear end portion of the peripheral wall portion 22. Thereby, the main body 20 is formed. Subsequently, as shown in FIG. 14(b), fix the outer frame 10 to the main body 20. Thereby, the chamber 1 is assembled. The outer frame 10 is fixed by screws or the like as appropriate. In the outer frame 10, actually, reinforcing metal fittings for connecting both the first side wall portion 22A and the second side wall portion 22C to strengthen the structure of the outer frame 10 and a hanging member for hanging the chamber 1 on the ceiling of the building are connected, but the description thereof is omitted in this specification.

[0074] <Measurement of Air Flow Rate> Next, with reference to FIGS. 15 and 16, the measurement of the air flow rate in the chamber 1 will be described. FIG. 15 is a schematic diagram showing the measurement method. As shown in FIG. 15(a), connect the chamber 102 to the blower 100 via the duct 120. Then, connect the chamber 102 and the chamber 1 via the duct 122. The chamber 102 is a configuration for adjusting the difference in diameter between the duct 120 extending from the blower 100 and the duct 122 connected to the chamber 1. The air blown from the blower 100 flows in the direction of arrow X1. In front of the chamber 1 (50 to 100 millimeters in front), a measurement probe 104 of a differential pressure gauge (mano-stager, for example, WO81 FS manufactured by Yamamoto Electric Works Co., Ltd.) and a measurement probe 106 of an anemometer (Anemomaster MODEL 6115 manufactured by Kanomax, Anemomaster measurement software MODEL 6000-40 manufactured by Kanomax) are arranged. The air volume is calculated based on the wind speed and the opening area of the passage.

[0075] As shown in FIG. 15(b), the wind speed is measured at the outlets 32A to 32D of the chamber 1. For each of the outlets 32A to 32D, the wind speed is measured at a plurality of positions P1 to P9 on the opening surface viewed from the arrows T1 to T4. The measurement probe 104 of the differential pressure gauge described above is also arranged at each of the positions P1 to P9 of the outlets 32A to 32D, and the difference from the static pressure in front of the chamber 1 is measured by the differential pressure gauge.

[0076] FIG. 16 is a diagram showing measurement data. The wind speed at the position in front of the chamber 1 where the measurement probe 106 was arranged was 5.5 meters per second (m / s). Also, the air volume was 980 cubic meters per hour (CMH: Cubic Meter per Hour).

[0077] At the four outlets 32A to 32D, a reference average wind speed is defined as 2.83 (m / s). If the deviation from the reference average wind speed at any of the outlets 32A to 32D is within 10%, it is assumed that the wind speed of the air flowing out from the outlets 32A to 32D is substantially the same and uniform. The average speed is the average speed of the wind speed measured at the positions P1 to P9 described above. In FIGS. 16(a) and 16(b), "A" indicates the outlet 32A, "B" indicates the outlet 32B, "C" indicates the outlet 32C, and "D" indicates the outlet 32D. The measurement results at each of the positions P1 to P9 are shown in FIG. 16(b). As shown in FIG. 16(a), the average speeds at the outlets 32A to 32D are from 2.76 (m / s) to 2.89 (m / s), and the deviation from the reference average wind speed of 2.83 (m / s) is within 3%. Therefore, it can be said that the wind speed of the air flowing out from the outlets 32A to 32D is substantially uniform.

[0078] Regarding the air volume, the reference average air volume is set at 245 CMH. If the air volume flowing out from any of the outlets 32A to 32D deviates from the reference air volume by within 10%, it is considered that the air volume flowing out from the outlets 32A to 32D is substantially uniform. The average flow rate of each of the outlets 32A to 32D is the average value of the flow rates calculated based on the wind speeds measured at the positions P1 to P9 described above and the respective opening areas of the positions P1 to P9. The measurement results at each of the positions P1 to P9 are shown in Fig. 16(b). As shown in Fig. 16(a), the average flow rates at the outlets 32A to 32D are from 238 CMH to 250 CMH, and since the deviation from the reference average wind speed of 245 CMH is within 3%, it can be said that the air volume flowing out from the outlets 32A to 32D is substantially uniform.

[0079] Regarding the pressure loss, the reference average pressure loss is set at 7 Pascals (Pa). If the actual pressure loss is 7 Pascals or less, it is evaluated that the pressure loss is sufficiently small. The pressure loss is calculated by averaging the differences between the static pressures in front of the chamber 1 and the static pressures at the respective positions P1 to P9 of each of the outlets 32A to 32D to obtain the pressure loss at each of the outlets 32A to 32D, and then averaging the pressure losses of the outlets 32A to 32D to obtain the final average value. As a result, the pressure loss was 3 Pascals. Therefore, it can be evaluated that the pressure loss is sufficiently small.

[0080] <Supplementary Explanation> Next, referring to Figs. 17 and 18, the air flow due to the configuration of chamber 1 will be described in comparison with the air flow outside the configuration of chamber 1. Figs. 17 and 18 are conceptual diagrams showing the air flow in chamber 1 and the like. In Figs. 17 and 18, the solid and dotted arrows indicate the air flow.

[0081] FIG. 17(a) is a conceptual diagram showing the air flow in chamber 1. Even if there are differences in wind speed or air volume at the orthogonal plane, the air flowing into chamber 1 from inlet 30 is made uniform by passing through mesh member 40. As a result, it becomes easier for air to flow into outlets 32A and 32B, and the air hits guide members 50A and 50B to change the traveling direction and easily flows toward outlets 32A and 32B. Since guide members 50A and 50B do not reach the central part in the width direction of chamber 1, some air flows toward the back wall part 26 side without hitting guide members 50A and 50B. As a result, some air directly flows into outlets 32C and 32D, and some air hits back wall part 26 to change the traveling direction and flows into outlets 32C and 32D. At this time, although the air as a whole flows from the front end wall part 24 side to the back wall part 26 side, when focusing on each air molecule, by passing through mesh member 40, it has a vector component in a direction different from the straight-ahead direction. For this reason, it is highly likely to hit at an angle other than 90 degrees instead of hitting the back wall part 26 at 90 degrees. Therefore, when the air hits the back wall part 26, it is highly likely to efficiently change the angle and flow into outlets 32C and 32D. As a result, the wind speed and air volume of the air flows Y1A to Y1D flowing out from outlets 32A to 32D are uniform, and since the pressure loss is small, it also saves energy.

[0082] FIG. 17(b) is a view showing chamber 1X. Unlike chamber 1, chamber 1X does not include the net-like member 40, and guide members 50A and 50B. When there are differences in wind speed or air volume on the orthogonal plane, the air flowing into chamber 1X from the inlet 30 flows through chamber 1X in that state toward the back wall portion 26. Here, even if there are no differences in wind speed or air volume on the orthogonal plane, since it is difficult for the air to diffuse in the orthogonal plane direction, the amount of air flowing along the first side wall 22A and the second side wall 22C sides is reduced. For this reason, it is difficult for air to flow into the outlets 32A and 32B. Most of the air directly hits the back wall portion 26, changes its traveling direction, and flows into the outlets 32C and 32D. For this reason, the air flows Y1AX and Y1BX flowing out from the outlets 32A and 32B are smaller in both wind speed and air volume than the air flows Y1CX and Y1DX flowing out from the outlets 32C and 32D. For example, in the case of air volume, the ratio of the front outlets 32A and 32B to the rear outlets 32C and 32D is approximately 2 to 8.

[0083] FIG. 18(a) is a diagram showing chamber 1Y. Different from chamber 1, chamber 1Y does not include guide members 50A and 50B. Even if there are differences in wind speed or air volume on the orthogonal plane, the air flowing into chamber 1Y from the inlet 30 is made uniform by passing through the mesh member 40. As a result, it becomes easier for air to flow into outlets 32A and 32B. However, most of the air flows toward the back wall portion 26 side. As a result, some of the air hits the back wall portion 26, changes its traveling direction, and flows into outlets 32C and 32D. At this time, although the air as a whole flows from the front end wall portion 24 side to the back wall portion 26 side, when focusing on each air molecule, by passing through the mesh member 40, it has a vector in a direction different from the straight-ahead direction. For this reason, it is highly likely to hit the back wall portion 26 at an angle other than 90 degrees. For this reason, when the air hits the back wall portion 26, it is highly likely to efficiently change the angle and flow into outlets 32C and 32D. In chamber 1Y, the air flows Y1AY and Y1BY flowing out from outlets 32A and 32B are smaller in both wind speed and air volume than the air flows Y1CY and Y1DY flowing out from outlets 32C and 32D. For example, in the case of air volume, the ratio of the front outlets 32A and 32B to the rear outlets 32C and 32D is approximately 3 to 7.

[0084] Figure 18(b) is a view showing chamber 1Z. Different from chamber 1, chamber 1Z does not include a net-like member 40. When there are differences in wind speed or air volume on the orthogonal plane, the air flowing into chamber 1Z from the inlet 30 flows in the state from the orthogonal plane toward the back wall 26 in chamber 1Z. Also, even if there are no differences in wind speed or air volume on the orthogonal plane, since it is difficult for the air to diffuse in the orthogonal plane direction, the amount of air flowing along the first side wall 22A and the second side wall 22C sides decreases. However, a part of the air hits the guide members 50A and 50B and changes the traveling direction to flow toward the outlets 32A and 32B sides. Since the guide members 50A and 50B do not reach the central part in the width direction of chamber 1, a part of the air flows toward the back wall 26 side without hitting the guide members 50A and 50B. As a result, a part of the air directly flows into outlets 32C and 32D, and a part of the air hits the back wall 26 and changes the traveling direction to flow into outlets 32C and 32D. For this reason, the air flows Y1AZ and Y1BZ flowing out from outlets 32A and 32B are smaller in both wind speed and air volume than the air flows Y1CZ and Y1DZ flowing out from outlets 32C and 32D. For example, in the case of air volume, the ratio of the front outlets 32A and 32B to the rear outlets 32C and 32D is about 4 to 6.

[0085] From the above, it is clear that the configuration of chamber 1 including the net-like member 40 and the guide members 50A and 50B is useful for equalizing the air flow rates flowing out from outlets 2A to 32D.

[0086] <Second Embodiment>

[0087] Next, referring to FIG. 19, a second embodiment will be described. The description of the parts common to the first embodiment will be omitted, and only the parts different from the first embodiment will be described.

[0088] As shown in FIG. 19(a), in the second embodiment, instead of the mesh member 40 of the first embodiment, a mesh member 40X is provided. The mesh body 40b3 is composed of a plurality of horizontal line portions 40b31 and a plurality of vertical line portions 40b32. Each surface 40b31s and 40b32s of the horizontal line portion 40b31 and the plurality of vertical line portions 40b32 is configured to be convex toward the inlet 30. Specifically, the surfaces 40b31s and 40b32s form an arc.

[0089] As shown in FIG. 19(b), the horizontal line portion 40b31 and the vertical line portion 40b32 are each formed with a semi-circular cross-section in their longitudinal directions. This reduces the possibility that the air hitting the mesh body 40b3 of the mesh member 40X receives a force in the opposite direction. <Third Embodiment>

[0090] Next, referring to FIG. 20, the third embodiment will be described. The description of the parts common to the first embodiment will be omitted, and only the parts different from the first embodiment will be described.

[0091] As shown in FIG. 20, in the third embodiment, instead of the mesh member 40 of the first embodiment, a mesh member 40Y is provided. The mesh body 40b4 is configured by combining a plurality of horizontal line portions 40b41 and a plurality of vertical line portions 40b42. Each surface 40b41s and 40b42s of the horizontal line portion 40b41 and the plurality of vertical line portions 40b42 is configured to be convex toward the inlet 30. Specifically, the surfaces 40b41s and 40b42s form an arc.

[0092] The horizontal line portion 40b41 and the vertical line portion 40b42 are each formed with a circular cross-section in their longitudinal directions. This reduces the possibility that the air hitting the mesh body 40b4 of the mesh member 40Y receives a force in the opposite direction. <Fourth Embodiment>

[0093] Next, referring to FIG. 21, the fourth embodiment will be described. The description of the parts common to the first embodiment will be omitted, and only the parts different from the first embodiment will be described.

[0094] As shown in FIG. 21, in the fourth embodiment, instead of the guide member 50 of the first embodiment, a guide member 51 (51A, 51B) is provided. Among the widths W6, the width of the base portion 51a is the width W7, and the width of the extending portion 51b is the width W8. The base portion 51a is a portion fixed to the main body 20, and the extending portion 51b is a portion extending into the internal space of the main body 20. The outer edge of the extending portion 51b is formed in a rectangular shape.

[0095] Note that the branch chamber of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. Further, the above embodiments can be appropriately combined as long as there is no technical contradiction.

Explanation of Reference Numerals

[0096] 1 Branch chamber 10 Outer frame 20 Main body 22 Peripheral wall portion 22A First side wall portion 22B Bottom wall portion 22C Second side wall portion 22D Ceiling wall portion 22a, 22b, 22c, 22d Opening 24 Tip wall portion 24b Opening 26 Rear wall portion 30 Inlet 32A, 32B, 32C, 32D Outlet 40, 40X, 40Y Mesh member 50A, 50B, 51A, 51B Guide member

Claims

1. A branch chamber having a chamber body in the shape of a hollow box that is long in one direction, wherein the chamber body has a tip wall portion, a rear wall portion, a first side wall portion, a second side wall portion, a bottom wall portion, and a ceiling wall portion, the first side wall portion and the second side wall portion are arranged at opposing positions, the bottom wall portion and the ceiling wall portion are arranged at opposing positions, a peripheral wall portion is formed by the first side wall portion, the second side wall portion, the bottom wall portion, and the ceiling wall portion, the tip wall portion is arranged so as to close the tip of the peripheral wall portion, the rear wall portion is arranged so as to close the rear end of the peripheral wall portion, an inlet for air to flow into the chamber body is connected to the tip wall portion, a plurality of outlets for air to flow out of the chamber body are respectively connected to the first side wall portion and the second side wall portion at different positions in the longitudinal direction, inside the chamber body, when the tip wall portion side is taken as the front and the rear wall portion side is taken as the rear, and a plane parallel to the inner surface of the tip wall portion and the inner surface of the rear wall portion is taken as the orthogonal plane, a flow rate equalization means for equalizing the flow rate of air flowing in the orthogonal plane is arranged in front of the outlet formed at the position closest to the inlet, between the plurality of outlets respectively connected to the first side wall portion and the second side wall portion, guide means is arranged so that a part of the air that has passed through the flow rate equalization means hits and changes the traveling direction and is guided to the outlet, a branch chamber.

2. The branch chamber according to claim 1, wherein the flow rate equalization means is a mesh member having an opening ratio of 50% or more.

3. The branch chamber according to claim 1, wherein the flow rate equalization means is a mesh member having an opening ratio of 60% or more and 80% or less.

4. The mesh member is composed of a plurality of openings and a mesh body that divides the openings, the mesh body is composed of a longitudinal line portion and a transverse line portion that are orthogonal to each other, the cross section of each of the longitudinal line portion and the transverse line portion in a direction orthogonal to the longitudinal direction is formed in a convex shape toward the inlet, the branch chamber according to claim 1.

5. The guide means is a plate-like member, when a line segment connecting the center of the inner surface of the tip wall portion and the center of the inner surface of the rear wall portion is taken as the center line, the guide means extends in a direction from the first side wall portion and the second side wall portion toward the center line, In the guide means, the portion extending in the direction toward the center line is formed in an arc shape when viewed from the tip wall portion side, and is configured such that the portion corresponding to the center line protrudes the most. The branch chamber according to any one of claims 1 to 4.

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