JPH0136830Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air nozzle that blows air onto a running web.

[Prior art]

Conventionally, in a web unwinding machine or winding machine, there is a dancer roll that absorbs tension fluctuations in the web and controls the tension to a constant level. Incidentally, in recent years, in the case of webs such as floppies and films for optical use, there is a problem of scratches on the surface, so it has been desired to perform the process without contact as much as possible. For this reason, there is a method of blowing air onto the web to perform the function of the dancer roll in a non-contact manner. An example of this is the device provided in Japanese Patent Publication No. 60-1258. This device is designed to blow air across the width of the web during the process of winding or unwinding the web.

In addition to the above devices, floater dryers are also used as devices for blowing air onto the web.

The air nozzles used in these devices are equipped with an outlet for blowing out air and an inlet for sucking the blown air, so that the air circulates.

In response to the air blown out from the outlet, the web is floated or pushed down depending on the orientation of the nozzle, and is pushed in the opposite direction of the nozzle and floated. In this case, if the wind speed of the blowout is high, the pressing force against the web will naturally be large. Therefore, if the tension is constant, the floating attitude of the web changes due to this variation in wind speed, and if the floating attitude is not constant, the tension changes. Therefore, in order to prevent such changes and fluctuations from occurring, it is only necessary to control the tension wind speed and temperature so that they are always constant, and this requires interlocking control of the tension and air pressure, which is a large-scale process. . In addition, the method of use that requires changing the tension, air volume, and speed depending on the purpose and the control method described above are contradictory, as there are problems such as web flapping and slight vibration, so the control method described above is not applicable. The range will be narrow. Furthermore, when tension fluctuations due to disturbances are applied to the web, the shock absorption effect is poor.

[Purpose of invention]

The present invention was devised in view of the above-mentioned circumstances, and the floating posture of the web is always constant and stable even if the supplied wind speed fluctuates, and the floating posture of the web is always constant and stable, and it is able to withstand fluctuations in the tension of disturbances applied to the web. On the other hand, the present invention provides an air nozzle that has a large shock absorption effect.

[Structure of the idea]

For this reason, the air nozzle of the present invention has an air nozzle that blows out air and an inlet that sucks the blown air, and a valve that opens when the outside pressure exceeds a certain level is installed with the inlet on the inside. This is what happens.

〔Example〕

Reference numeral 1 generally indicates an air nozzle, and reference numeral 2 indicates an outer frame thereof.The outer frame 2 has a substantially shaped cross-sectional shape and is long from front to back in FIG. Inside the outer frame 2, an inner frame 3 is disposed in the upper part,
An air supply passage 4 is formed in the lower cavity.

The inner frame 3 also has a substantially shaped cross-sectional shape, is attached along the longitudinal direction of the outer frame 2, and gaps are formed between the side surfaces 3a, 3a of the inner frame 3 and the side surfaces 2a, 2a of the outer frame 2. The gap is used as an air outlet 8.

A cover plate 4 is attached to the upper surface of the inner frame 3. A suitable number of air suction ports 5 are formed in the cover plate 4 at appropriate positions, and a valve 6 is attached to the inner surface of the suction port 5. Thus, an air exhaust passage 7 is formed in the cavity surrounded by the inner frame 3 and the cover plate 4.

Although not clearly shown in the drawings, both longitudinal ends of the outer frame 2 and inner frame 3 are surrounded by walls.

[Effect]

The air supplied to the air supply passage 4 is blown out from the air outlet 8. The ejected air hits the web W running on the front side of the air outlet 8 and presses it. Therefore, if the air outlet 8 is facing upward and the web W is traveling above it, the web W will be floated; When the web W is running, the web W is naturally pushed downward.

For example, when a plurality of air nozzles 1, 1 are arranged alternately in opposite directions as shown in FIG. 5, the web W assumes a wavy floating attitude.

The air hitting the web W is repelled and escapes from the longitudinal direction of the web and from the air nozzles 1, 1 side. When the flow velocity of the air blowing out from the outlet 8 is low, the back pressure of the air hitting the web W is also low, and although the valve 6 closes the suction port 5, the flow velocity of the air increases and becomes a high wind velocity. If the above-mentioned back pressure is increased, the valve 6 opens the inlet 5, air flows into the air exhaust passage 7 from the inlet 5, and the air exhaust passage 7
is released to the outside. (The passage is not shown.) In this case, the opening amount of the valve 6 to the inlet 5 depends on the magnitude of the back pressure, that is, the flow rate of the air. Therefore, as the air flow rate increases, the opening of the suction port 5 becomes larger, and the amount of air escaping from the suction port 5 also increases. Therefore, the pressing force against the web W does not increase in proportion to the increase in the air flow velocity.

[Effect of idea]

The present invention is as described above, and since a valve is provided at the suction port, even if the flow velocity of the air ejected from the discharge port fluctuates within a certain range, the pressing force of air against the web can be automatically controlled. The floating position of the web can be maintained stably. In other words, the range of application to fluctuations in air wind speed is widened.

In addition, when there is a tension fluctuation on the web due to a disturbance, the valve opens and closes as appropriate, so that the effect of absorbing tension fluctuations on the web is greatly increased.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an embodiment of the present invention;
The figure is a bottom view of the valve part in Figure 1, Figure 3 is a sectional view of Figure 2, Figure 4 is a plan view of Figure 1, and Figure 5 is a sectional view showing an example of the usage state of the present invention. It is.

Claims (1)

[Scope of utility model registration request] An air nozzle having an outlet for blowing out air and an inlet for sucking the blown air, the air nozzle having a valve installed inside the inlet that opens when the outside pressure exceeds a certain level.