In the oil and gas industry, operators drill and produce hydrocarbons in all areas of the world. Many times, the operations are in offshore waters and/or remote regions. In some of these environments, the areas are in warm to hot climates. The need to keep employees cool during the hot months is not only for comfort but also safety, as heat exhaustion and stroke are real possibilities. In today's industry, operators may have a dedicated employee whose only job is to walk the location and give cold water to employees. Another tool used by operators to keep workers cool is the use of fans. Fans have been around for many years and they are driven by all types of power—mechanical, electrical, pneumatic, hydraulic, etc. The act of turning a fan blade directly or by belt is known in the art.
Hydraulic fans have been tried in the past for personnel cooling but the inevitable hydraulic leaks cause the fans to blow oil on the deck and onto personnel. As understood by those of ordinary skill in the art, drilling and production rigs have many safety regulations due to the hazardous working environment. Therefore, rigs and operating companies not wanting the liability, resorted to mostly electric fans. Evaporative fans are by far the most common and commercially available from several manufactures under the trade names such as Port-A-Cool and Cool Space. This is the preferred method used on drilling rigs. Low pressure misting fans are not used because the larger drops of the air create slicks. Mist fans are available but are not used because of this limitation. They are only available in 120V operation which limits the horse power and therefore the volume of air. The water available on land drilling rigs is very bad in quality as it comes straight out of the ground without any treatment. This water would stop up the mist nozzle which range from 0.008″ to 0.020″. More volume is needed because their area are located outside where wind can adversely affect the effectiveness of a misting of evaporative fan.
In general, portable fans consist of a motor and a blade. With the prior art portable evaporative fans (PEF) and misting fans, a means for introducing moisture (humidity) in the air stream is utilized. The moisture introduced in PEF's generally includes a cardboard with perforated holes placed in the suction side of the fan blades. Water is pumped on the top of the cardboard and the water flows down the length. Moisture is picked up as the air passes through the holes in the wet cardboard. Most common sizes come in 36″ and 48″ blades. The prior art fans tend to be large in size and weigh a significant amount. A misting fan sprays water and uses electrical motor to turn the fan blades. This is only available in 120V without filtration.
Also, prior art fans run off 120V system. A standard outlet is 15 amps or max of 20 amps, and hence two ⅓ HP motors are the maximum horsepower available, therefore, limiting the possible cubic feet per minute (CFM) airflow there through, since the horsepower and airflow (CFM) are directly related.
Additionally, with the PEF's, all of the air flow containing moisture flows over the electric motors, belt and pump causing motor failure at a high rate. As those of ordinary skill in the art will appreciate, the electric system has to be explosion proof when used on hazardous locations, which in turn adds to the cost, size and weight of the fans, and are limited to a single speed. As understood by those of ordinary skill in the art, safety is compromised because the electric cord is laying on a wet metal deck and is often cut by the moving of heavy equipment, as on a drilling and production rigs. The cardboard becomes less effective by the collection of dirt as is often common on locations with caliche or limestone, or in dry, desert like conditions. The water tank area also collects the dirt and blocks the pump suction. A typical misting fan would have an electric motor but would not be able to control the speed or amount of mist.