JPH0830477B2 - Cross flow blower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cross flow fan in which an impeller is rotatably mounted in a casing.

(B) Prior Art As a structural example of a cross flow fan in which an impeller is rotatably installed in a casing, a structure disclosed in Japanese Utility Model Publication No. 58-24099 is disclosed.

According to this content, the guide member having the tongue portion of the impeller is arranged in the lower front portion of the impeller, and the back wall of the casing facing the impeller has a smooth spiral curved surface shape.

Then, by rotating the impeller, a vortex is formed near the tongue, and the vortex causes the air in the casing to be guided from the suction port to the discharge port.

(C) Problems to be Solved by the Invention In such a cross-flow fan, since the guide member is located in the lower front part of the impeller, the width dimension of the air duct formed by the guide member and the casing is determined. Could be smaller. When the width of the air passage is reduced in this way, the amount of discharged air may decrease.

The present invention is intended to suppress a decrease in the amount of air discharged from a cross flow fan to a small extent.

(D) Means for Solving the Problems In order to achieve this object, the present invention arranges the wall surface of the tongue portion substantially orthogonal to the line passing through the center point of the impeller, and determines the length of this wall surface. Dimension h is 10% to 35% of the outer diameter dimension D of the impeller
With the apex of this tongue and the line passing through the center point of the impeller as the horizontal axis, and the coordinates perpendicular to this horizontal axis and passing through the center point of this impeller as the vertical axis, (0.1D,
A circle with a diameter of 0.15D centered on (-0.15D) is (-0.4D,-
A circle with a diameter of 0.3D is drawn with the center at 0.1D), and the scroll part with the center point set in the area connecting both circles as the ends is formed on the casing of the impeller.

(E) Action By increasing the length of the wall surface of the tongue facing the impeller, the vortex flow generated by the rotation of the impeller is stabilized, and this vortex flow and the flow along the scroll of the casing have almost the same speed. It was designed to be

(F) Embodiment FIG. 1 is a vertical sectional view of an indoor unit 1 of a separation type air conditioner, 2 is a main body, and 3 is a front grille mounted from the front of the main body. This front grill 3 has a suction port 4 at the top.
However, the discharge ports 5 are provided in the lower portions, respectively.

The main body 2 includes a heat exchanger 6, a drain pan 7 for receiving drain water attached to the heat exchanger 6, and a cross flow fan for exchanging heat between a refrigerant flowing in the heat exchanger 6 and room air ( And an impeller) 8. The diameter D of this cross flow fan 8 is 90 mm. The back surface of the main body 2 also serves as a casing 9 of the cross flow fan 8 as a smooth curved shape (described later). Drain pan 7
The rear portion also serves as the tongue portion 10, and the wall of the tongue portion 10 is composed of the facing wall 11 facing the cross flow fan 8 and the outlet wall 12.

The dimensional relationship between the diameter D of the casing 9 and the cross flow fan 8 and the tongue portion 10 is as described below.
That is, the opposing wall 11 of the tongue portion 10 is arranged so as to be orthogonal to the x-axis 50 connecting the apex of the opposing wall 11 and the center point 14 of the cross-row fan 8, and the dimension h of the opposing wall 11 is 22 mm. 13 is a y-axis that is orthogonal to this x-axis and passes through the center point 14 of the cross flow fan. Reference numeral 15 is an area where the center points 17 and 18 of the scroll portion 16 of the casing are located, and this area 15 is determined as follows. Ie x-axis 50
And y-axis 13 as coordinate axes, draw a circle with a diameter of 13.5 mm centering on point A (9 mm, -13.5 mm), and point B (-36 mm, -13.5 m
m) is a circle with a diameter of 27 mm, and the upper and lower parts of both circles are connected by a straight line. The first scroll 19 is a part of a circular arc having a radius of 52 mm with the center point 17 as the center.
A second scroll 20 is connected to the first scroll 19 and is a part of an arc having a radius of 72 mm with the center point 18 as the center. Reference numeral 21 is a straight line portion and is connected to the second scroll 20. Further, 22 is an angle (enlargement angle) formed by the tangent line 23 of the first scroll 19 and the tangent line 24 of the cross flow fan 8 and is set to 17 °.

In the cross-flow blower arranged in such a dimensional relationship,
When the cross flow fan 8 is rotated, the air sucked from the suction port 4 is subjected to the heat exchange action in the heat exchanger 6, and then flows as shown by the solid line arrow in FIG. Ie tongue 10
A vortex 25 is formed diagonally above the opposing wall 11 of the. And the first
Air 26 flowing along the scroll 19 and the second scroll 20
Extends substantially concentrically with the center of the vortex 25. In this way, the air flowing along the scroll is straight part 21 and the outlet wall.
It is guided to the discharge port 5 at 12 and. FIG. 3 shows the experimental results of this cross flow fan, in which the horizontal axis represents frequency and the vertical axis represents noise value. From this figure, the noise is relatively low at almost any frequency, and is almost unnoticeable. It is considered that this is because the velocity of the air 26 flowing along the scrolls 19 and 20 is slightly lower than or equal to the velocity of the vortex 25. The dimension h of the facing wall 11 of the tongue portion 10 is 22 mm.
However, the range of this dimension h is 10% of the diameter D of the impeller 8.
~ 35% is good. Also, the angle between the opposing wall 11 and the x-axis 50 is
When the angle is around 90 ° ± 10 °, the vortex 25 formed obliquely above the facing wall 11 of the tongue portion 10 becomes stable. Further, when the centers of the scrolls 19 and 20 are set to the above-mentioned region 15, it is considered that air easily flows along the bulge of the scrolls 19 and 20 if the enlargement angle 22 is in the range of 5 ° to 25 °.

FIG. 4 shows another embodiment of the cross flow fan of the present invention,
The center points 29 and 30 of the first scroll 27 and the second scroll 28 are set within the area 15 and the enlargement angle is set to 6 °, respectively. Then, by rotating the cross flow fan 8, the fifth
It is considered that the air flows as shown in the figure, and in this case as well, the flow 31 along the scrolls 27 and 28 is considered to spread concentrically in the center of the vortex 32 as in the case of the wind flow shown in FIG. .

Next, five types of cross-flow blowers in which the center of the arc of the scroll is set outside the area 15 will be described. In FIG. 6, the center points 35 and 36 of the scrolls 33 and 34 are set above the area 15 and the enlargement angle is set to -1 °. In this case,
Since there is no bulge in the scrolls 33 and 34, the flow 37 near the scrolls becomes faster, and it is considered that the vortex 38 also becomes faster accordingly (see FIG. 7). As a result, a high frequency sound (peak sound) of 33.7 dB was generated at 715 Hz as shown in FIG.

Similarly to FIG. 6, FIG. 9 also shows the center points of the scrolls 39 and 40.
41 and 42 are set above the region 15 and the enlargement angle is set to 5 °. Also in this case, since the casings 39 and 40 have no bulge, the flow 43 near the casing is shown in FIG. As a result, high-frequency sound is expected to be generated.

In FIG. 11, the center point 45 of the scroll 44 is set below the area 15 and the enlargement angle is set to 30 °. In this case, the bulge of the scroll 44 is too large, and as shown in FIG. A part of the air 46 in the vicinity of 44 does not follow the scroll 44 and a vortex 47 is generated, the flow velocity of the air 46 in the vicinity of the scroll 44 decreases, and the amount of air blown from the discharge port 5 decreases.
Further, as shown in FIG. 13, a high frequency sound (peak sound) of 28.6 dB was generated at 732 Hz.

14 and 16 also scroll below area 15.
The center points 50, 51, 54 and 55 of 48, 49, 52 and 53 are set, and the enlargement angles are set to 17 ° and 18 °, respectively. All of them are scrolled as shown in Fig. 11. The bulge is large and vortices 55 and 56 are generated inside the scroll (see FIGS. 15 and 17), and a decrease in the amount of air blown from the discharge port 5 is expected.

If the center point of the scroll is set outside the area 15 as shown in FIGS. 6, 9, 11, 14 and 16, the shape of the scroll does not follow the flow of air. Becomes

The table below shows the air volumes of the blower of the present invention (Fig. 1) and the blower used in the experiment (Figs. 6 and 11).
The blower of the present invention obtained a larger air volume.

(G) Effect of the Invention As described above, according to the present invention, the length of the wall surface of the tongue portion facing the impeller can be increased to make the vortex flow generated by the rotation of the impeller stable. It is possible to suppress a decrease in the amount of air blown. Moreover, since the shape of the casing of the impeller is substantially concentric with the vortex, the speed of this vortex and the speed of the flow along the scroll are substantially the same, and the noise discharged from the discharge port can be suppressed to a low level.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a heat exchange unit using a cross-flow fan according to an embodiment of the present invention, FIG. 2 is an explanatory view showing the flow of air in the unit, and FIG. 3 is a view showing the use of this blower. FIG. 4 is a noise characteristic diagram, FIG. 4 is a sectional view of a heat exchange unit using a cross-flow fan according to another embodiment of the present invention, and FIG. 5 is an explanatory view showing the flow of air in the blower shown in FIG. 6 and 9
FIG. 11, FIG. 14, FIG. 14 and FIG. 16 are cross-sectional views of the blower in which the center point of the scroll is set outside the region shown in the present invention, respectively, FIG. 7, FIG. 10, FIG. 15 and 17 are explanatory views showing the flow of air in the blower shown in FIGS. 6, 9, 11, 14, and 16, respectively, and FIG. 8 and FIG. 6
FIG. 12 is a noise characteristic diagram when the blower shown in FIG. 11 is used. 7 ... Guide member, 8 ... Cross flow fan, 9 ... Casing, 10 ... Tongue, 15 ... Area, 17, 18 ... Center point, 19, 20 ... Scroll.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-49-80608 (JP, A) “Study on cross-flow fan (1st report) Transactions of the Japan Society of Mechanical Engineers (Part 2) No. 41, 347 (Showa) July 1975) P.2062 "Study on cross-flow blowers (2nd report) Proceedings of the Japan Society of Mechanical Engineers (Part 2) Volume 41, No. 347 (July 1975) P.2076-P.2089

Claims (1)

[Claims] 1. A cross flow fan in which an impeller is housed in a casing, and a guide member serving as a tongue portion of the impeller is arranged in front of the impeller, wherein a wall surface of the tongue portion is located at the center of the impeller. They are arranged substantially orthogonal to the passing line, and the length dimension h of this wall surface is 10% to 35% of the outer diameter dimension D of the impeller.
In the coordinates with the horizontal axis as a line passing through the apex of the tongue and the center point of the impeller and the vertical axis as a line orthogonal to the horizontal axis and passing through the center point of the impeller, (0.1D , −0.15D)
Draw a circle with a diameter of 0.15D centering around, and a circle with a diameter of 0.3D centering around (-0.4D, -0.1D), and use the scroll with the center point in the area where both circles are connected to each other. A cross-flow blower formed in a casing.