Most restaurants use bulk quantities of cooking oil for frying food and require a method or apparatus for bulk storage of both fresh and spent (used or waste) oil. Waste cooking oil can be recycled for use in cattle feed, bio-fuels, soap and other products. There are a multitude of recyclers willing to collect waste cooking oil from restaurants on a routine basis. In some instances, restaurants would deposit their waste cooking oil in drums that were typically stored outside where they were picked up when full.
Many attempts have been made to transport waste oil from cooking fryers to metal holding containers that made it easier for recyclers to collect the waste oil. These attempts have various disadvantages associated therewith, as handling and storing of waste cooking oil at restaurants is labor intensive, hazardous, and wasteful. Restaurant personnel were subject to hot oil burns, slipping on greasy floors, or injury due to lifting and pouring waste oil into a holding tank. Additionally, conventional tank storage systems may have been bulky or heavy.
Service providers that collect waste cooking oil from restaurants for recycling have an incentive to provide improved equipment for the handling and storage of waste cooking oil. Un-warmed waste oil must be heated to make it sufficiently fluid to be poured or pumped out of the holding container into a tanker truck for removal. Waste oil that is temporarily stored outside the restaurant can attract animals, become contaminated, and cause a slick hazardous walking surface.
Today there are service providers that provide their restaurant customers improved equipment that make it safer, less labor intensive and cleaner to transfer the waste oil from the fryers to the oil holding tank for periodic collection. These tank storage systems are sufficiently translucent so that the oil level can be viewed from outside the tank so that when the oil level reaches a predetermined level, the service provider may be contacted for collection. These systems may also include a liquid level sensor or switch that can signal a high level or overflow condition to make restaurant personnel aware that the service provider should be contacted immediately. The use of a high level alarm is particularly useful for automatic storage tank systems that include a pump to transfer heated waste cooking oil directly from the fryers or cookers to the holding tank. Automatic storage tank systems are convenient for restaurants but can cause problems due to unexpected equipment failure such as failed pumps, automatic valves, heaters, and stuck or clogged liquid level sensors or switches.
Accordingly, there is a need for a storage tank assembly and control system that addresses the various issues presented with conventional storage tank assemblies.