Industrial upblast and hooded roof propeller fan ventialtors. Sales of power roof and wall ventilators for air exhaust and make-up, as well as replacement props.
Buffalo Fan Company



Canada Blower Co. has developed Low Profile Positive Pressure Ventilators that have been designed to fit in tight compartments and small spaces without sacrificing performance or features. These compact ventilation blowers are available is both gasoline driven configuration and with 115/230V single phase electric motor:
           
The Positive Pressure Blower is a high volume fan use to pressurize a burning structure, in case of fire, in order to force the smoke out. Positive Pressure Blowers are portable, gasoline powered fans, most of which utilize a 5.5 horsepower engine.
 
The theory of positive pressure ventilation is based on the principal of even pressure distribution. Once a structure is pressurized, air and smoke can be forced out through any opening (similar to escaping from an inflated balloon).
 
Electric smoke ejectors (negative pressure ventilation) can be used for smoke removal but this has proven to be inferior to positive pressure ventilation:
 
What makes Positive Pressure Ventilation superior to negative pressure ?
 
* The risk of injury from the engaged structure is reduced while placing the fan in operation.
* Positive pressure ventilation is faster to set up and requires fewer personnel.
* The Positive Pressure Blower has a self contained power source, while electric fans require cords and adaptors.
* Smoke and heat is removed from all levels of the structure unlike negative pressure which can result in localized extraction.
* Quicker results. After initial knockdown, positive pressure ventilation can be initiated and will show immediate improvements in the interior conditions.
* It allows replacement of contaminants with vital cooler, cleaner air - especially in sealed or windowless buildings. It's also very effective in large and compartmentalized buildings, warehouses, schools, etc.
* Quick results allow firefighters faster entry due to lower heat levels and improved visibility.
 
The following criteria should be considered for effective use of Positive Ventilation:
 
- The cone of air must cover the intake opening.
 
The fan must be placed the correct distance from the structure such as that the cone of air forms a seal around the opening.

- The size and location of the discharge is important.
 
The discharge, if at all possible should be as high and far away from the intake as is practical. The discharge size should be between 3/4 to 1/2 times the intake. This may not always be possible as the fire may have already dictated discharge locations and sizes; but whenever there is a choice, the above criteria should be used.

- It is important to control the air flow between the intake and discharge.
 
Positive pressure ventilation can move air long distances if proper control is maintained by opening and closing doors, windows, etc. It is important that firefighters understand not to open the structure too much: ie breaking windows, etc.
 
The standard features of Canada Blower Positive Pressure Ventilators include: fold down "T" handle; 8" pneumatic tires with full width axle; a "tilt and lock" device that allows the unit to be angled 20 degrees up or down with infinite positions in between; sturdy and light 1 inch wrap around frame. Explosion proof electric motors are available as drivers too.
 
The optimum ventilator placement distance on most 6' 6" doors is about five to six feet away. If placement is too close, the seal won't be achieved. If placement is too far away, the cone of air will be hitting well outside the opening.


























































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Roof ventilators work in both summer and winter.  In summer, roof ventilators reduce the build up of heat in the ceiling spaces, reducing the heat load on your insulation, meaning that the insulation works more effectively.  In turn, you will save on your electricity bills as the air-conditioning systems will not have to work as hard.  In winter, it reduces the amount of condensation that forms when warm, moist air from exhaust fans meets cold surfaces.  Roof ventilators will also reduce the amount of corrosion and timber that occurs because of condensation.   Roof ventilators should be installed where there is sarking underneath tiled roofs, when metal deck roofing is used, and when there is evidence of condensation in the roof spaces or ceilings.

Proper building ventilation requires that there be a movement or circulation of the air within the space and that the temperature and humidity be maintained within a range that allows adequate evaporation of perspiration from the skin. It was formerly believed that the discomfort, headache, and lethargy commonly associated with poor ventilation were caused entirely by the increase in the amount of carbon dioxide and the decrease in the oxygen content of the air. There is evidence to show, however, that the deleterious effects result largely from interference with the heat-regulating mechanism of the body. Lack of air currents and the increase in relative humidity and temperature (especially noticeable in crowded, poorly ventilated places) prevent normal evaporation of perspiration and loss of heat from the surface of the skin.

A simple roof ventilator is essentially an opening in the roof with a cover to keep out rain and to prevent winds from interfering with its functioning. Natural convection is an appreciable aid to ventilation in a large building only if it contains sources of large amounts of heat. A further useful adjunct is a fan fan, device for agitating air or gases or moving them from one location to another. Mechanical fans with revolving blades are used for ventilation, in manufacturing, in winnowing grain, to remove dust, cuttings, or other waste, or to provide draft for a fire. The addition of distribution ducts to the fan and a system for forcing air into the building provides greater efficiency. Outlets are designed to attain maximum mixing of air and to move large amounts of air at low velocity so that temperature layers are eliminated. Factories have special suction hoods and enclosures to draw away localized dust, fumes, and heat. Incoming air may be cleaned of dust by filters or electrostatic precipitators.

Natural ventilation depends on winds outside and convection currents inside a building. Winds raise air pressure slightly on the windward side of a building and lower it slightly on the lee side. The pressure difference promotes circulation into the building on the windward side and out of it on the lee side. Convection currents are caused by the sinking of colder and therefore heavier air, which displaces the warmer air. A building may have a roof ventilator to allow the rising warm air to escape. If there is an opening to the outside at the bottom of the building, fresh, cool air will be drawn in.

Deep mines, underwater tunnels, and other subterranean and submarine environments require elaborate mechanically operated systems for maintaining the air supply in a healthful condition. The lives of those working in, or traveling through, such areas depend upon a constant supply of fresh air; not only must the systems used be highly efficient, but there should be provision for emergencies in case of failure of the apparatus in operation. An outgrowth of studies of problems of ventilation is the development of methods of air conditioning heat pump is a reversible device that does mechanical work to extract heat from a cooler place and deliver heat to a warmer place. The heat delivered to the warmer place is, approximately, the sum of the original heat and the work done.

Such systems, unlike ordinary methods of ventilation, are independent of outdoor atmospheric conditions and can, therefore, maintain the indoor atmosphere at the most healthful temperature and humidity and can free the air of dust and other undesirable materials. They accomplish this, however, at a considerable cost in energy.