JPS6325353Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a fan shaft/bearing cooling device for an air conditioning fan.

(Prior art) Conventionally, as shown in FIGS. 1 and 2, fan shafts 4, 4 supporting a fan 3 of a fan casing 2 installed in a chamber 1 are supported by bearings 6, 6 in the chamber 1. However, an air conditioning fan has been put into practical use that sucks air into the chamber 1 from the suction port 7 of the chamber 1 through the rotation of the fan 3, and discharges it out of the chamber 1 from the discharge port 8 of the fan casing 2. -Refer to Publication No. 3129).

When such an air conditioning fan is used as a smoke exhaust fan in the event of a building fire or as a heat exhaust fan in a high temperature workplace (such as a molten steel factory), the fan shaft 4 and bearing 6 are exposed to high temperatures.

Now, if we only think about Fanshaft 4,
There is a risk of damaging the bearing 6 due to thermal expansion.For this reason, it is possible to use a special fan shaft 4 with low thermal expansion, but this is expensive and has problems in terms of durability.

It is also possible to absorb the thermal expansion of the fan shaft 4 with the bearing 6, but it is necessary to set a large bearing clearance, and the smoke exhaust fan or exhaust heat fan must be In cases where it is also used as an air fan, the bearing clearance is too large because the fan shaft 4 does not normally expand thermally.
There are problems in that the fan 3 vibrates during rotation and generates noise, and the durability of the fan shaft 4 is reduced.

On the other hand, if we consider bearing 6, chamber 1
The influence from the ambient temperature inside the fan shaft 4
Since the bearings are simultaneously affected by heat conduction from the bearings, it is necessary to use water-cooled or oil-cooled bearings, or special bearings with an expensive heat-resistant structure using heat-resistant grease.

In addition, there is a type in which the fan shaft 4 is passed through a through hole formed in the side wall of the chamber 1 and supported by a bearing outside the chamber.In this type, the heat-resistant structure of the bearing is relatively simple, but the fan shaft is extremely It is extremely difficult to manufacture because it is long (approximately 3 meters or more).

Additionally, an intake duct is provided between the bearing outside the chamber and the chamber, and the fan shaft inside the intake duct is covered with a sleeve to cool the fan shaft with external air (Utility Model Publication No. 49-111209).
(see Japanese Utility Model Publication No. 103602/1983), and a method in which a heat insulating cover is provided on the bearing inside the chamber and the bearing is cooled with external air (see Utility Model Application Publication No. 103602/1983), but the external air is not supplied to the sleeve or the heat insulating cover. There was a problem that heat loss occurred in the conditioned air because the air was constantly introduced from the air.

(Purpose of the invention) The present invention aims to effectively cool the fan shaft and the bearing to minimize the thermal expansion of the fan shaft and the thermal influence on the bearing, and at the same time to suppress the heat loss of the conditioned air. This is the purpose.

(Structure of the invention) Therefore, in the present invention, the bearing inside the chamber is installed in the bearing cover, and the bearing cover is communicated with the outside of the chamber by the first wind guide member, and the bearing cover is connected to the fan shaft. A second wind guide member is provided extending inward of the chamber across a predetermined wind guide gap along the side, while an equal amount adjusting plate and an emergency air supply valve are provided for the first wind guide member. It is something.

When the inside of the chamber becomes negative pressure due to the rotation of the fan, the first air guide member uses the suction negative pressure to introduce cooling air (room temperature) outside the chamber into the bearing cover. A cooling air layer (air curtain) is formed around the outer circumference of the covered bearing, which blocks heat from the high-temperature wind inside the chamber while also effectively cooling the inside of the bearing.
The second wind guide member introduces the cooling air introduced into the bearing cover further along the fan shaft, thereby uniformly cooling the outer circumference of the fan shaft covered by the wind guide member. An air layer (air curtain) is formed, which blocks heat from the high-temperature wind inside the chamber and at the same time effectively cools the inside of the fanshaft. In addition, the cooling air discharged into the chamber from the tip end of the second wind guide member is sent out along the fan shaft to the front end of the fan shaft because the guide passage in the wind guide member is sufficiently long. , the fan shaft is cooled over almost its entire length.

This series of cooling effects by the cooling air minimizes thermal expansion of the fan shaft, heat conduction, and thermal effects on the bearings.

(Effects of the invention) According to the invention, the bearing is effectively cooled by the air curtain formed by the bearing cover via the first wind guide member, so even if the bearing is installed inside the chamber, there is no direct contact with the bearing. Thermal effects are now suppressed to a minimum, and the fan shaft is effectively cooled over almost its entire length by the air curtain formed by the second wind guide member, reducing thermal expansion of the fan shaft. will be kept to a minimum.

Therefore, even when used as a smoke exhaust fan or a heat exhaust fan, standard specification fan shafts, bearings, etc., which are inexpensive and easy to maintain, can be used as they are, and durability is greatly improved.

Of course, even when used as a normal air blowing/exhausting fan or return air fan, there is no need to provide a large bearing clearance, so the fan will not vibrate and generate noise.

Furthermore, the introduced air is narrowed down by the air volume adjustment plate, and the cooling air passes uniformly around the outer periphery of the bearing and fan shaft, promoting cooling. Since it opens only in emergencies, outside air is introduced only in emergencies, thereby suppressing heat loss.

(Example) Portions having the same structure and function as those of the prior art shown in FIGS. 1 and 2 are given the same numbers, and explanations thereof will be omitted.

As shown in FIGS. 3 and 4a and 4b, the bearings 6, 6 in the chamber 1 are covered with a hollow bearing cover 10,
Installed within 11.

The bearing cover 10 on the left side in the figure is located away from the side wall 1a of the chamber 1, so the fan shaft 4
The through hole 1b of the side wall 1a formed coaxially with the through hole 10b of the bearing cover 10 is connected to the first wind conduit 12.
Connect via.

Since the bearing cover 11 on the right side of the figure is connected to the side wall 1a of the chamber 1, the through hole 1b formed in the side wall 1a and the through hole 1 facing the bearing cover 11
1b directly. This direct connection portion constitutes a first wind conduit.

On the other hand, through holes 10c and 11c formed on the other sides of the left and right bearing covers 10 and 11 have pipe-shaped holes extending inwardly into the chamber 1 along the fan shaft 4 with a predetermined uniform air guide gap t between them. The second wind pipes 13, 13 are connected.

The length of the second wind conduit 13 is preferably set as long as possible without interfering with the rotation of the fan 4.

When the air guide gap t is used as a smoke exhaust fan, the temperature of the bearing 6 is maintained even when there is heat conduction from the fan shaft 4 and thermal influence when the ambient temperature inside the chamber 1 reaches 560°C. The amount of cooling air introduced is set so that the fan shaft 4 is cooled to a temperature below 100°C.

In addition, the through holes 1b, 1b of the left and right side walls 1a, 1a
For this purpose, it is preferable to provide air volume adjusting plates 14, 14 for narrowing down the introduced air so that the cooling air passes uniformly around the outer periphery of the bearings 6, 6.

Note that the fan shaft 4 and bearing 6 are of standard specifications.

When the fan 3 is rotated by a motor (not shown) via the fan shaft 4, smoke or hot air is sucked into the chamber 1 from the suction port 7 of the chamber 1 along with air, and from the discharge port 8 of the fan casing 2. It is ejected out of chamber 1.

When the inside of the chamber 1 becomes negative pressure due to the rotation of the fan 3, suction negative pressure acts on the through hole 1b of the side wall 1a, and the cooling air (normal temperature) outside the chamber 1 is supplied to the first air guide through the air volume adjustment plate 14. When introduced into the bearing covers 10 and 11 via the member 12, the bearing 6
An air curtain is formed around the outer periphery of the bearing 6, so that heat from the high-temperature wind inside the chamber 1 is cut off, and at the same time, the inside of the bearing 6 is also cooled.

In addition, the cooling air in the bearing covers 10 and 11 flows through the wind guide gap t between the fan shaft 4 and the second wind pipe 13.
When the air is introduced from the inside of the fan shaft 4, an air curtain of uniform thickness is formed around the outer circumference of the fan shaft 4, which blocks heat from the high temperature air inside the chamber 1 and at the same time cools the inside of the fan shaft 4. will be done.

Furthermore, the cooling air discharged from the tip end 13a of the second wind conduit 12 is sent out along the fan shaft 4, so that it is cooled to the tip side of the fan shaft 4, and eventually the fan shaft 4 reaches almost the entire length. It will be effectively cooled.

As a result of the heat resistance test, the atmospheric temperature of chamber 1 was
In the case of 560℃, the temperature of the bearing 6 was 300 to 560℃ in the conventional method shown in FIG. 1, but in this embodiment shown in FIG.
The temperature was below 100℃.

There is no problem when the smoke exhaust fan or heat exhaust fan with the above configuration is used also as a normal ventilation fan, but when it is used also as a ventilation fan or return air fan, the ventilation hole 1b of the side wall 1a is Since cooling air is constantly introduced, a heat loss of 1 to 2% occurs in the conditioned air.

For this reason, the air pipe 1 is only used in emergencies (smoke exhaust fan when a fire occurs, heat exhaust fan when high temperature occurs).
It is preferable to configure the cooling air so that it is introduced from the rear end port 12b of No. 2.

Therefore, in the case of a smoke exhaust fan, chamber 1
An emergency air supply valve 16 may be provided that opens the through hole 11b when the ambient temperature inside reaches 80° C. or higher.

Further, for both the smoke exhaust fan and the heat exhaust fan, a system may be adopted in which the emergency air supply valve 16 is opened in conjunction with a temperature sensor or manually.

5 and 6 are modified examples in which the first air pipe 12 of the bearing cover 10 on the left side of the figure is bent into an L shape and connected to the through hole 1b of the upper wall 1c of the chamber 1. , a plate-shaped second wind conduit 13 is connected to the through hole 10c of the bearing cover 10.

In the above embodiment, a double suction type air conditioning fan in which the two fan shafts 4, 4 of the fan 3 are supported by two bearings 6, 6 is taken as an example. Needless to say, the present invention can also be applied to a single suction type air conditioning fan in which the fan shaft is supported by one bearing 6.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of a conventional fan shaft cooling device for an air conditioning fan, Fig. 2 is a side sectional view of Fig. 1, and Fig. 3 is a fan shaft/bearing cooling device for an air conditioning fan according to the present invention. Front sectional view, Figure 4a is an enlarged view of the left bearing in Figure 3, Figure 4b is the third
FIG. 5 is a front sectional view of a modified fan shaft/bearing cooling device, and FIG. 6 is an enlarged view of the left bearing in FIG. 5. 1... Chamber, 1a... Side wall, 1b... Through hole, 2... Fan casing, 3... Fan, 4
...fan shaft, 6 ... bearing, 7 ... suction port, 8 ... discharge port, 10, 11 ... bearing cover,
12...First wind pipe, 13...Second wind pipe, 16
...Emergency air supply valve, t...Wind guide gap.

Claims (1)

[Claim for Utility Model Registration] A fan shaft that supports a fan of a fan casing installed in a chamber is supported by a bearing in the chamber, and air sucked into the chamber from the suction port of the chamber by rotation of the fan,
The air-conditioning fan discharges air out of the chamber from the outlet of the fan casing, wherein the bearing is installed in a bearing cover, the bearing cover is communicated with the outside of the chamber by a first wind guiding member, and the bearing cover is connected to the bearing cover. A second wind guide member is provided along the fan shaft and extends inward of the chamber across a predetermined wind guide gap, while an air volume adjustment plate is provided for restricting the introduced air to the first wind guide member, and only in an emergency. A fan shaft/bearing cooling device for an air conditioning fan, characterized by being provided with an emergency air supply valve that opens an inlet.