Cross flow fan system

In a cross flow type fan according to the present invention having a tongue section provided between the rear guide surrounding the cross flow fan, the back side and bottom side thereof and the front side of the fan, a projecting section (flow changing board) is provided on the rear guider, the shape of the tongue section is caused to be different at the middle section and at both ends of the axial direction of the fan, the boundary section of the suction opening and the discharge opening of the air is divided on the outward circumferential surface of the fan by the partition wall having continuous through holes, and the air flow direction control blade being curved toward the discharge side.

BACKGROUND OF THE INVENTION 
The present invention relates to a cross flow fan system which is utilized 
for air conditioners and various other types of air conditioning systems. 
Example 1 of the conventional cross flow fan: 
The cross flow fan used in a conventional air conditioner is equipped with 
a suction opening for air and a discharge opening 2 as shown in FIG. 4. 
This fan has a heat exchanger 5 and a cross flow fan 4 in the casing, and 
a tongue section 3 and a heat guider 6 for stabilizing the air flow. In a 
construction of a conventional cross flow fan such as this, in order to 
reduce the depth of the casing, the hear exchanger 5 is installed so that 
the lower end of the heat exchanger 5 is above the shaft of the fan. 
With the above-construction for a cross flow fan, the direction of the air 
flowing into the cross flow fan 4 is brought close to the vertical 
direction as shown by the actual line 9. The vortex flow above the part 7 
where the rear guider 8 and the outer circumferential surface of the fan 
are closest becomes difficult to generate. On the other hand, air which 
does not flow into the cross flow fan 4 from the part 7 increases as shown 
by the broken line. This air flows directly into the discharging direction 
along the rear guider 6, resulting in a deterioration of discharged air 
vollume and noise characteristic. 
Example 2 of the conventional cross flow fan: 
FIG. 6 is a structural diagram of a cross flow fan for a conventional air 
conditioner. As shown in FIG. 6, the conventional cross flow fan 
incorporates a cross flow fan 101 in a casing 103, and at a position close 
to the outer circumferential surface of the fan, a tongue section 102 is 
provided having the same cross section (which plays a role of dividing the 
suction side and discharge side) in an overall area in the direction of 
the shaft of the fan. Incidentally, 104 represents a discharge opening. 
In this case, the discharge flow rate at both ends 104a of the fan shown in 
FIG. 7 is less than that of the middle section 104b of the same fan. There 
is a possibility of generating a reverse suction flow depending on the 
shape of the tongue section 102, causing instability in the discharge flow 
rate of the fan. Furthermore, if a load 105 such as a heat exchanger is 
provided on the suction side of the fan, there is a possibility to easily 
generate surging of the discharged air flow particularly in the low air 
volume range. 
In order to solve the above-mentioned problems, there has been an attempt 
to stabilize the discharged air flow at both ends 104a of the fan by 
providing from the side plate a protruding portion (projection) 106 as 
shown by oblique lines on both ends 104a of the discharge opening. By 
using this method, the discharge flow rate of both ends 104a of the fan 
increases, making it difficult for surging to occur. However, depending on 
the position where this projection 106 is to provided or the shape 
thereof, detailed experiments become necessary and there was a possibility 
of reduced discharge flow rate in some cases. 
Example 3 of the conventional cross flow fan: 
As shown in FIG. 15, the conventional fan is provided with a suction 
opening 202 for taking in the open air at the front of the casing 201, a 
discharge opening 203 is provided thereunder, and a fan 204 is freely 
rotatably on a portion surrounded by a partition board 205 and a rear 
guider 201' in the air duct connected to the blow off opening 203 from the 
aforementioned suction opening 202. 
The partition board 205 provided between the aforementioned suction opening 
202 and the discharge opening 203 is intended to eliminate the 
short-circuit flow between the two openings and a blind patch is used for 
this purpose. 
In addition, in the above example of the conventional cross flow fan, when 
the fan 204 is rotated in the direction indicated by the arrow, the air 
flow "a" is generated and sent out from the discharge opening 203. In this 
case, eccentric eddy "b" having its center inside the fan is generated in 
a portion where the partition board 205 and the fan 204 are close to each 
other, so that turbulent flow "c" is generated to flow around the 
eccentric eddy "b" and to cause pulsating current to be generated in the 
discharged air flow or to reduce the discharged air volume. 
The magnitude and position of the eddy of accessory current generated 
secondarily depend on the shape and installed position of the partition 
board 205 and the number of revolutions of the fan and other factors. In 
order to maintain these factors under stabilized conditions, the eccentric 
eddy is stabilized at a fixed position by adjusting the number of 
revolutions of the fan so that the discharged air flow without pulsation 
can be obtained. 
In such a case as above, it was extremely difficult to find an optimum 
shape and position for the partition board 205 according to the number of 
revolutions of the fan 204 and the load on the suction side. 
Example 4 of the conventional cross flow fan: 
As shown in FIG. 18(a) and FIG. 18(b), in the construction of the cross 
flow fan used conventionally for air conditioners and the like, an air 
flow direction control blade 305a which is a is provided at the discharge 
opening formed between the rear guide 302 enclosing the fan 301 and the 
stabilizer 303 of the front panel 304. The control blade 305a is flat 
board like blade which does not curve in either direction. When an upward 
air discharge flow is desired, the air flow direction control blade 305a 
is maintained almost horizontally as shown in FIG. 18(a). Therefore, 
because a large space is formed between the inward upper surface of the 
air flow direction control blade 305a and the upward piece 303' in this 
case, the air flow "b" such as cold air or hot air is obtained from the 
discharge opening between the lower surface of the air flow direction 
control blade 305a and the extended upper surface of the rear guide 302 
while the eddy like air flow "a'" is being generated in this space. In 
addition, when downward air flow is desired and the aforementioned air 
flow direction control blade 305a is set vertically as shown in FIG. 
18(b), the air flow "b'1" generated above the circumference of the fan 301 
collides with the air flow directin control blade 305a almost at a right 
angle because the air flow direction control blade 305a is flat. The air 
flow "b'1" is then blown downward by the internal pressure which increases 
after collision. 
In this case, as is apparent from the constructions shown in FIG. 18(a) and 
FIG. 18(b), when the air flow direction control blade 305a is set 
horizontally, the space formed by the aforementioned air flow direction 
control blade 305a and the upward pieces 303' of the stabilizer 303 
becomes wider causing stagnation. Therefore there is a possibility that 
sufficient air volume cannot be obtained at the discharge opening. 
Furthermore, when the aforementioned air flow direction control blade 305a 
is set vertically, the air flowing along the rear guide 302 collides with 
the aforementioned air flow direction control blade 305a almost at a right 
angle. This collision causes the force for pushing the air flow downward 
to be diminished, and therefore there is also a possibility in this case 
that sufficient air volume cannot be obtained and that this arrangement is 
not effective. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to solve the above-mentioned 
conventional problems. 
With respect to the example 1 of the conventional cross flow fan, the cross 
flow fan according to the present invention is provided with a flow 
changing board over the entire axial direction above the portion where the 
rear guider and the outward circumferential surface of the fan are closest 
to each other. 
With respect to the example 2 of the conventional cross flow fan, the cross 
flow fan according to the present invention is composed so that the shape 
of the tongue section in close vicinity to the outward circumferential 
surface of the fan is caused to be different at both ends of the fan and 
at the middle section of the fan. 
With respect to the example 3 of the conventional cross flow fan, the cross 
flow fan according to the present invention is provided with a partition 
board for short-circuiting which has continuous through holes at a 
position on the outward circumferential surface of the fan where the 
suction opening and the discharge opening of the air are separated. 
With respect to the example 4 of the conventional cross flow fan, the cross 
flow fan according to the present invention is provided with an air flow 
direction control blade which is curved in one direction and mounted 
freely pivotably at the discharge opening section formed between the rear 
guide enveloping the fan and the stabilizer of the front panel. 
In the first, above-described invention, because the air current which 
flows in without flowing through the fan from the neighboring section of 
the rear guide and fan is restricted and the air current flowing into the 
cross flow fan is increased, it is possible to increase the discharged air 
volume. 
In the second, above-described invention, by composing the shape of the 
tongue section in close vicinity to the outward circumferential surface of 
the fan to be different at the middle section and at both ends of the 
axial direction of the fan, it is possible to improve the instability of 
the air flow at both ends of the discharge opening and to increase the 
flow rate. 
In the third, above-described invention, the air flow is generated from the 
suction opening to the discharge opening by rotation of the fan, and by 
causing a part of the air flow sent out from the discharge opening to flow 
back from the secondary side to the primary side of the aforementioned 
partition board by means of the through hole thereof, the position of the 
eccentric eddy is caused to be fixed by the short-circuit flow. 
In the fourth, above-described invention, when the direction of the air 
flow direction control blade is changed, by reducing the corner space 
formed by the stabilizer and by the curve of the aforementioned air flow 
direction control blade, a reduction in the air flow stagnation and an 
increase in the discharged air volume results. 
As has been described for the first embodiment, according to the present 
invention, by the flow changing board provided above the portion where the 
rear guider and outward circumferential surface of the fan are closest to 
each other, it is possible to increase the air flow which flows through 
the cross flow fan and to provide an excellent effect for increasing the 
discharged air volume. 
As have been described for the second embodiment, according to the present 
invention, it is possible to increase the discharge flow rate at both ends 
of the fan and to also achieve stabilization of the discharged air flow at 
these ends of the fan. In addition, considerable effect is achieved to 
improve, for example the overall instability of the discharged air flow in 
the low air volume range when a load such as a heat exchanger is provided 
on the suction side of the fan. 
The third embodiment is an invention of high practical value, which has an 
excellent effect such as, for example, to stabilize the eccentric eddy at 
a fixed position without being moved by factors such as changes in the 
number of revolutions and the fluctuation of the load at the suction 
opening of the fan and to cause the discharged air volume to increase by 
means of a simple construction because the cross flow fan of the present 
invention is composed in a manner as described above. 
Because the fourth embodiment is composed in a manner as described above, 
by using a air flow direction control blade of simple construction, it is 
possible to reduce the eddy current and to discharge the air at high 
efficiency when the aforementioned air flow direction control blade is 
held horizontally. 
In addition, when the air flow direction control blade is set vertically, 
the cross flow fan of the present invention is capable of reducing the 
resistance of the air flow at the discharge section so as to achieve 
efficient air blowing and to reduce the thickness of the cross flow fan 
because of simple construction. 
Further scope of applicability of the present invention will become 
apparent from the detailed description given hereinafter. However, it 
should be understood that the detailed description and specific examples, 
while indicating preferred embodiments of the invention, are given by way 
of illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent to those skilled in 
the art from this detailed description.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The first invention is accomplished in order to solve the problems of the 
example 1 set forth above for conventional cross flow fan and will 
hereafter be described with reference to the embodiment shown in FIG. 1. 
The same symbols in FIG. 1 as those used in FIG. 4 denote the same 
contents and therefore the descriptions thereof will now be omitted. That 
is to say, in this embodiment, a flow changing board 10 is provided over 
the entire axial direction of the fan above the portion 7 where the rear 
guider 6 and the outward circumferential surface of the fan are closest to 
each other. 
By providing the construction of above, the air current which flows in 
without flowing through the cross flow fan from the part 7 is restricted 
as shown by the streamline 8' and the air current flowing into the cross 
flow fan 4 increases. Therefore, it becomes possible to increase the 
discharged air volume. 
The cross flow fan 4 is rotated to suck the air into the body 1 from the 
suction opening 1. The air sucked into the body 1 gives and receives heat 
energy with the heat medium in the heat exchanger 5 while the air passes 
through the heat exchanger 5 and the air is further subjected to the 
driving action of the cross flow fan 4 to be discharged from the discharge 
opening 2. While the air is being discharged, the air current 8' flowing 
along the rear guider 6 in the casing collides with the flow changing 
board 10 to move toward the center of the casing, and then flows through 
the cross flow fan 4. 
FIG. 2 is a detailed diagram of the cross flow type fan shown in FIG. 1 
which is used to confirm the effect of the above embodiment through 
experiments and is provided with a flow changing board 10 having a width 
of 15 mm with respect to the diameter of 70 mm of the cross flow fan 4. 
FIG. 3 shows an example of the test results illustrating a relation between 
the number of revolutions and the air volume. 
From FIG. 3, the effect of this embodiment is shown as an increase in the 
air volume of about 1 m.sup.3 /min for the same number of revolutions. 
According to the present invention as described above, it is possible to 
increase the discharged air volume of a cross flow type fan by means of an 
extremely simple construction, and the industrial effect thereof is very 
large. 
For the shape of the tongue section of the example 2 of the conventional 
cross flow fan, the one shown in FIG. 5(1) is common and is designed so as 
to obtain high air volume. As compared with the shape of the tongue 
section of FIG. 5(1), FIG. 5(2) shows the shape of the tongue section 
whose space with the outward circumferential surface of the fan is widened 
by tilting (107') the portion of the tongue section (tip of the tongue 
section) 107 in close vicinity of the outward circumferential surface of 
the fan so as to move away from the outward circumferential surface of the 
fan than the portion 107 shown in FIG. 5(1). 
With regard to the shape of the tongue section shown in FIG. 5(1) and FIG. 
5(2) respectively, FIG. 8 shows a comparison of experimental results for 
the static pressure distribution at the discharge opening 4. From the 
results shown in FIG. 8, it is known that the shape of the tongue section 
shown in FIG. 5(2) has higher static pressure distribution than that shown 
in FIG. 5(1). 
In the second invention, the shape of the tongue section shown in FIG. 5(2) 
is provided at both ends 104a of the fan, the entire tongue section is 
composed in the middle section 104b by using the shape of the tongue 
section shown in FIG. 5(1), and by increasing the static pressure of the 
discharged air flow at both ends 104a of the discharge opening higher than 
that at the middle section 104b, the pressure characteristic of the 
discharged air flow at both ends 104a is improved so as to obtain better 
stability. 
FIG. 9 is a diagram in which the wind velocity distribution of the 
discharged air flow in the axial direction of the fan is compared between 
the case where the tongue section according to the present invention is 
used and the case of the tongue section of the conventional cross flow 
fan, and it is known that the flow rate at both ends 104a of the present 
invention is increased. 
As described above, according to the present invention, it is possible to 
improve the instability of the air flow at both ends 104a of the discharge 
opening which has conventionally been a problem. In addition, a 
considerable improvement, for example in the overall instability of the 
discharged air flow in the low air volume range is obtained when a load 
such as a heat exchanger is provided on the suction side of the fan. 
As a transformed embodiment of the present invention, in the case of the 
circular arc tongue section as shown in FIG. 10(1), the same effect can be 
obtained by providing at both ends 104a the tongue section which is tilted 
in the shape 108' so as to move the tip 108 of the tongue section shown in 
FIG. 10(1) from the outward circumferential surface of the fan as shown in 
FIG. 10(2). 
The third invention will be described in detail by the embodiment shown in 
FIG. 11. The suction opening 202 for taking in the open air is provided at 
the front section of the casing 201 of the fan as shown in FIG. 11, the 
discharged opening 203 is formed thereunder, the fan 204 is freely 
rotatably at a portion surrounded by the lower edge 202' of the suction 
opening and the rear guider 201' in the air duct connected from the 
aforementioned suction opening 202 to the discharge opening 203. In the 
corner section between the aforementioned fan 204 and the aforementioned 
lower edge 202' of the suction opening and on the aforementioned lower 
edge 202' of the suction opening, the partition board 205a is formed with 
continuous through holes 206a, 206a . . . comprising one or a plurality of 
slots which are fixed as shown in FIG. 12(a). The short circuit flow is, 
therefore, caused to be generated between the suction side, that is the 
primary side and the discharge opening, that is, the secondary side. 
Furthermore, the aforementioned continuous through holes 206a, 206b . . . 
are provided on the plane 207 formed on the partition board 205a so as to 
intersect almost at a right angle with the outward circumferential surface 
of the fan 204. In addition to the aforementioned continuous through hole 
206a, circular continuous through holes 206b, 206b, . . . may be drilled 
as shown in FIG. 12(b). 
The operation of the aforementioned fan will be described. 
When the fan 204 is rotated in the direction of the arrow, the air current 
"a" sucked in from the suction opening 202 is blown off from the discharge 
opening 203 as the air current "a'". And, by the rotation of the fan 204, 
the eccentric eddy "b" is generated by the influence of the intersecting 
section formed by the aforementioned partition board 205a and the 
aforementioned fan 204. While the eccentric eddy "b" is being generated, 
the outer layer thereof collides with the plane 207 of the partition board 
205a and tries to flow outward through the discharge opening 203, but 
because of the existence of the aforementioned continuous through hole 
206a or 206b, a part of the air current on the secondary side blows back 
to the primary side to form the stabilized short circuit flow "d". Because 
the eccentric eddy "b" is retained at a fixed position by the stabilized 
short circuit flow "d" formed in the primary side, the influence upon the 
main air current "a" by the fluctuation of the aforementioned eccentric 
eddy will be eliminated. 
FIG. 14 (where A represents the case of FIG. 13 and B th case of FIG. 15) 
shows that characteristics of the number of revolutions versus the air 
volume of the fan 204 of the cross flow fan used for testing shown in FIG. 
13, in which the diameter of the continuous through hole 206b is .phi.1=4 
mm, the distance between the fan 204 and the inner edge of the partition 
board 205b is L.sub.2 =7 mm, the diameter of the aforementioned fan 204 is 
.phi.2=70 mm, and the distance between the fan 204 and the rear guider 
201' is L.sub.1 =4 mm. In the case of the present invention, however, as 
compared with the conventional cross flow fan, more discharged air volume 
is obtained per the same number of revolutions by about 0.5 m.sup.3 /min, 
and further a stabilized proportional characteristic is demonstrated with 
respect to the number of revolutions of the fan. 
In the above, the length of the continuous hole 206a or the diameter and 
the number and other factors of the circular continuous hole 206b are not 
limitative of the above embodiment. 
With respect to the fourth embodiment, as shown in FIG. 17, a discharge 
opening such as for example for warm or cool air is formed between the 
rear guide 302 surrounding the fan 301 and the stabilizer 303 of the front 
panel 304, and between the stabilizer and the frontal section 302' of the 
rear guide 302 the air flow direction control blade 305. One end section 
305' of the blade 305 is curved upwardly (15' in this case) and the blade 
305 is installed to be held horizontally or vertically. 
That is to say, the most essential point of the present invention is that 
when the air flow direction control blade 305 is held horizontally, the 
direction of the curve and inclination of the blade 305 is such that the 
tip 305' thereof is caused to curve on the circumference of the fan 301 in 
a direction directly facing the rotational direction of the fan 301 and 
that when the end section 305' of the air flow direction control blade 305 
is held vertically, the other end section is composed to curve inward from 
the outer surface of the front panel 304 so as to extend toward the 
direction of the stabilizer 303. 
Now, the operation of the air flow direction control blade of the present 
invention according to the above construction will be described. When the 
air flow direction is to be directed upward, because the end section 305' 
of the air flow direction control blade 305 and a part of the corner of 
the upward piece 303' of the stabilized 303 is reduced by the curve of the 
end section 305' and the air current stagnation is reduced as a result of 
setting the air flow direction control blade 305 horizontally as shown in 
FIG. 18(a), the scale of the eddy current "a" caused by the stagnation is 
reduced and it becomes possible to obtain sufficient air current "b" from 
the discharge opening formed between the air flow direction control blade 
305 and the tip section 302' of the rear guide 302. 
Furthermore, when the air flow direction is to be directed downward, by 
directing vertically the end section 305' of the air flow direction 
control blade 305 as shown in FIG. 17(b), the air current "b.sub.1 " 
generated by the fan 301 blows strongly along the tip section 302' of the 
rear guide 302 and the upper part of the air flow direction control blade 
305 is inclined inwardly from the front surface of the front panel 304. 
Therefore, because the end section 305' of the air flow direction control 
blade 305 does not intersects with the air current "b.sub.1 " at a right 
angle and becomes inclined toward the direction of the discharge opening, 
thereby reducing the flow resistance and the scale of the eddy current 
"a.sub.1 ". 
The present invention is designed to smooth the air current in a manner as 
described above by providing a curve at the tip of the air flow direction 
control blade and to prevent stagnation of the air flow. 
While only certain embodiments of the present invention have been 
described, it will be apparent to those skilled in the art that various 
changes and modifications may be made therein without deparing from the 
spirit and scope of the present invention as claimed.