Nozzle insert for a Yankee impingement hood
The present invention includes a nozzle insert for use in a drying machine of the type used in paper web drying. The nozzle insert of the present invention includes at least one intake having a central portion, wherein a pair of center vanes is disposed for directing airflow. The central portion is bounded by at least one turning vane adapted for directing airflow in a lateral direction. For each turning vane, there is at least one straightening vane adapted for curtailing swirling of the airflow. The vanes are oriented at optimal angles for directing the flow of the nozzle in a lateral direction, while permitting some air to penetrate the central portion through a series of ports. The intakes are bounded by a series of insulated bulkheads, which serve to direct airflow and contain heat-loss through thermal emission.
1. A nozzle insert for a web-drying machine of the type including a nozzle box for directing airflow at a web, the nozzle insert comprising:
an intake having a central portion;
at least one hollow bulkhead disposed lateral to the intake and filled with an insulating material;
a pair of center vanes which define a plurality of entry ports, such that the pair of center vanes are disposed within the central portion for directing;
a turning vane disposed lateral to the central portion, the turning vane adapted for directing airflow in a lateral direction; and
a straightening vane disposed on the turning vane, the straightening vane adapted for curtailing swirling of the airflow.
2. The nozzle insert of claim 1 wherein the insulating material is mineral wool.
3. The nozzle insert of claim 1 wherein the nozzle insert is comprised of a low emissivity material.
4. The nozzle insert of claim 3 wherein the low emissivity material is aluminized steel.
5. The nozzle insert of claim 1 wherein the turning vane defines a first surface, and further wherein the straightening vane is perpendicular to the first surface.
6. The nozzle insert of claim 1 wherein the pair of center vanes define a first angle, and further wherein the first angle is between 90 and 170 degrees.
7. The nozzle insert of claim 6 wherein the first angle is 144 degrees.
8. A web-drying machine comprising:
a crescent header;
a nozzle box receiving air from the crescent header and directing airflow at a web; and
a nozzle insert disposed within the nozzle box, the nozzle insert comprising an intake having a central portion, at least one hollow bulkhead disposed lateral to the intake and filled with a mineral wool insulating material, a plurality of entry ports defined by a pair of center vanes, such that the pair of center vanes are disposed within the central portion for directing airflow, a turning vane disposed lateral to the central portion, the turning vane adapted for directing airflow in a lateral direction, and a straightening vane disposed on the turning vane, the straightening vane adapted for curtailing swirling of the airflow.
9. The machine of claim 8 wherein the nozzle insert is comprised of a low emissivity material.
10. The machine of claim 9 wherein the low emissivity material is aluminized steel.
11. The machine of claim 8 wherein the turning vane defines a first surface, and further wherein the straightening vane is perpendicular to the first surface.
12. The machine of claim 8 wherein the pair of center vanes define a first angle, and further wherein the first angle is between 90 and 170 degrees.
13. The machine of claim 12 wherein the first angle is 144 degrees.