A VENTRY Fan set up on stairs, out of the way of firefighters. Click here for more photos from this training burn.
VENTRY Fans have specific advantages over conventional fans which all sit close to the ground.
Entrainment and Air Cones: The elevated position of a VENTRY Fan allows the geometry of aiming squarely at the entrance so a door seal or entrainment through the entry is much easier to establish. Whether you subscribe to the conventional Cone of Air / Door Seal or newly termed Straight Stream Airflow concepts, entrainment is happening if the fan is properly positioned and it leads to increased air volume. Air stream momentum is preserved (less of the fan air stream bounces off the ground) so fresh air drives deep into the structure instead of bouncing off the ceiling. Entrainment is illustrated in the above images (entrainment through the door, not through the shroud/guard/cage!) Click to enlarge them. Note: The illustrations are to scale; the fan is realistically sized in relation to the door.
Out-of-the-Way: We do a lot of engineering and design work on our propellers to create a uniform, tight air stream. Call it whatever you want (Power Stream, Pow-Air technology, whatever) but VENTRY Fans have always had a very narrow air stream which allows for placement very far back from the target, due to their propellers (12 feet or more is ideal and the farther the better in most cases!). Combined with all-terrain, independently adjustable legs, this means that you can put our fan back in the rose garden and let your firefighters use the sidewalk for advancing their hose line! VENTRY Fans should be placed farther away than most users believe, generally 8 to 12 feet from the entry point, out of the way. With VENTRY Fans, it is much better to be too far away than too close (click here for why). It is primarily the tight air cone of VENTRY Fans that allows them to be placed far back from the target.
Each leg on a VENTRY Fan adjusts, giving them endless versatility, as shown here, set up on the stairs and ventilating a wind turbine. Photo courtesy of Arturo Arnalich. More photos.
Legs: The tripod frames/legs on VENTRY Fansalso help allow them to be set further back, because they elevate the air stream over the stairs instead of needing to be tipped. (Legs also prevent the pickup/ejection of debris, allow greater air supply to the prop, and stand on uneven ground and over obstacles like hose…)
Standard fans must be propped up with additional items, or must be aimed upwards which often activates the engine oil alert features and shuts them down, just when they are most needed. By aiming horizontally/directly into the structure from a ways back, VENTRY Fans also provide minimal disturbance to the thermal balance – they don’t bounce the air off the ceiling but instead push fresh air directly into the lower portion of the structure.
Airstream Quality: Further, the quality of the air stream on a PPV Fan is very important. If you hold a handkerchief in front of any multiple-blade fan and move it around within the air stream, you will find that the strength of flow varies greatly within the circular plane. The strongest points are often at the outer edges of the circle and hit the outside of the door when properly sealed, thereby leaving the weakest points in the center to enter the structure. With VENTRY Fans, the air cone is very focused and uniform across the entire stream. You won’t lose the strongest part of the air stream on the edges of the door (or shadowed on the ground) – instead, the air is directed into the structure.
Instead of a VENTRY Fan, fire fighters were using a conventional fan (without legs) during ventilation training and noticed from the backside of the structure that not much air was coming out. When they checked on the fan, they found that it had sucked in leaves from all around in a 15-foot radius and was plugged, because it was on the ground. That won’t be a problem with their new VENTRY Fan! ~ As told by Fire Fighter Purk in Oak Harbor, Ohio