Aqueous Degreasing Tank

The Air Force is looking for one heated, insulated, ventilated tank that will hold an alkaline cleaning solution (concentration 10-30% in water, pH above 9), and must operate up to 180°F. Note: this tank will be operated 24hrs/day, 7 days/wk). Tank Interior dimensions: Depth: 110” Width: 44” Length: 116” Fitting within an overall footprint not to exceed: Depth: 130” Width: 74” Length: 136” (including ventilation ducts, insulation, and required plumbing installed). Tank to be constructed of 0.25” (or thicker) carbon steel with a minimum of three 4” wide carbon steel reinforcing channel girths that are appropriately spaced to ensure no visible bulging of the tank when it is filled and heated to operating temperature (180°F). The tank must also have a carbon steel channel rim at top that is 4” wide and minimum ¼” thick. Note: The tank must not leak when filled with water and heated to 180 degrees F. More than three channels may be required in order to ensure no visible bulging of the tank (at the discretion of the contractor). Channel girths must be at least a minimum 0.25” thickness. The four vertical sides of the tank must be completely insulated on the exterior with rigid insulation that is at least 2” thick with a 16 gauge (or thicker) steel sheath covering the insulation. A steam heat exchanger of plate or tube design shall be mechanically mounted to the tank and must be two dimensional in design, capable of maintaining a working tank temperature of 180 degrees F, mounted approximately 3” from the back wall (the back wall is the long end that has the ventilation, see diagram). Steam heat exchanger and the supply and condensate lines shall be plumbed above the back wall of the tank with inlet/outlet lines plumbed above the ventilation duct work, standard fittings must be provided to facilitate ease of connection. Steam lines shall be insulated on all areas above the top level of the ventilation channel. Steam lines shall minimally interfere with ventilation (the steam line shall not be plumbed with a horizontal section that interferes with the ventilation collection slot). Steam heat exchanger must be equipped with a Watlow controller. The controller shall be rated for industrial duty in wet/corrosive environments, have a digital readout, and be manually programmable. A thermocouple shall be provided that is mounted to the tank and wired to the Watlow controller to facilitate control and feedback of the solution temperature. Steam supply is approximately 20 psi. The tank must be fitted with CPVC ventilation duct work. Ventilation must exhaust the back (steam coil) side of the tank. Hood shall extend the length of the tank (116" long) length with (1) collection slot 3" high extending the length of the tank, two (2) exhaust plenums 13” wide X 28” deep, 2” drip lip into process tank I.D., two 12” dia. outlet connections with butterfly dampers and to extend 14” below the hood plenum. The ventilation ductwork must be reinforced as necessary to withstand up to 2” (water) pressure drop. The top (horizontal surface) of the ductwork must be at least ½” thick CPVC. The tank must be fitted with CPVC push air piping mounted to the front (long side opposite the steam coils) of the tank. Push air piping will be 2” diameter pipe or minimum 2” square (see diagram). Push air holes do not need to be drilled by the contractor, they will be drilled on site by the government. The push air piping must include a vertical 2” feed pipe and ball valve. The tank must be supplied with a fill line and associated plumbing. The plumbing shall be minimum 1” internal diameter and must include four 90 degree elbows and 8 feet of minimum 1” internal diameter pipe. The contractor shall supply one 90 degree ball valve (1” size) and one manually actuated 1” valve that is spring loaded and normally in the closed position (requiring the operator to physically hold the spring loaded handle in the open position to allow water to fill the tank). The contractor shall supply any couplings or other hardware necessary for assembly. Line supply water pressure is 100 psi. The spring loaded valve must be made of metal. All valves and piping supplied must be compatible with eachother for easy assembly. The tank must be supplied with a tank level sensor that has a manually adjustable limits (min/max). The tank must be supplied with mechanical agitation that the Air Force will mount to the short (44”) side of the tank. Mechanical agitation must be sufficient enough to create a rolling turnover of the tank contents. Intensity or speed of mechanical agitation must be user adjustable via a variable speed drive or other similar means. Impellers used must be shielded by using a cage or section of steel pipe or other similar means for protecting any components lowered into the solution from making contact with the moving mechanical parts. Chem-flowtronics has developed similar systems for the Air Force in the past and they may be able to assist with this application. Our current tanks rest on two length-wise I-beams which are each 6.5” wide with 24” between them. The new tank must be engineered to sit on these I-beams.