Midwest Mixing Inc., builds Vertical Mixers in various styles and designs: direct drive, geared, electrical or air driven (at speeds suitable) for the impellers used, the tank dimensions, the mixing objectives, and the fluids involved). Mountings can be furnished for use on tanks made of steel, fiberglass, wood or other materials, open or closed, with or without vacuum or pressure, jacketed or non-jacketed, with or without internal heating elements. Tanks should preferably be cylindrical, with height equal to diameter. Otherwise, power requirements and number of mixers may vary. Propellers may not be used in extremely shallow tanks. Shaft diameters are selected with critical speed considereations in mind. Steady or foot bearings or stabilizers may also be required. Other factors such as flash point, settling rates, head room, viscosity, uniformity, sensitivity to shear, particle size reduction, etc., must be considered in selecting the proper mixer type and size.
Motors are constructed to NEMA standards, and are available: continuous duty; foot or face mounted constant/multi/variable speed; AC, D.C.; open; totally enclosed or explosion-proof, as required. Motors can include all standard electrical characteristics and are used either directly, or with speed reducers, to provide the speed required by the application and the impeller used. AIR MOTORS may be a very important alternative to electric motors. Hydraulic motors can also be supplied.
Speed Reducers conform to AGMA standards and are designed specifically for mixing applications for the service class indicated. Gear housings are made of close-grained free machining aluminum alloy or close-grained semi-steel machined to interchangeable tolerances and close bearing-fits. Seals are double lipped and suitable for the lubricant used. Provision is made for easy addition or drainage of lubricant used. Provision is made for easy addition of drainage of lubricant and measurement of its level. Helical and/or spiral bevel gears are normally used (with hardened and ground teeth for strength and long wear). Where thrust loads require them, tapered roller output shaft bearings are used. Compact design high mechanical efficiency and smooth, quiet operation are always our prime objective.
Variable Speed may be accomplished electrically through the use of DC motors and SCR rectifier/speed controllers, for operation from AC sources; or through AC motors and variable frequency controllers. Mechanically, speed may be varied with variable pitch pulleys or with various cone, disc or fluid speed variators (with or without gear reducers), depending on the speed range desired. We invite your inquiries.
Pedestal Supports may be made of cast aluminum of cast iron from our own patterns designed for mixing applications; or fabricated from steel. They are designed for rugged, rigid, support of the motor/reducer drive weight, to provide maximum protection of personnel from moving parts, and to maintain strict alignment of the impeller shaft with the reducer output shaft or motor shaft.
Impellar Shafts are selected for straightness, concentricity, and freedom from mars due to mishandling. They can be supplied for any length required, although splicing couplings may be necessary. Critical speeds are closely watched; shaft diameters are used, which in conjunction with impeller number, weight, and locations, avoid critical speed by plus or minus 25%. Shaft materials are selected to properly handle the corrosive conditions of the specific job requirements.
The Flange Cartridge Bearing is a doubly sealed ball bearing mounted in a grey iron casting with an accurately machined tenon drilled for bolting to the flange (and with a collar having a pair of set screws or a locking ring for locking to impeller shaft), and a grease fitting.
The Stuffing Box is usually welded to the flange center on top side and contains a lantern ring of suitable material for distribution of lubricant (Teflon impregnated asbestos or other suitable packing comptible with tank contents); a grease fitting which may be replaced with a ram for automatic lubrication; a packing gland designed to stay put; and with the standard number of bolts for the pressure involved.
The Mechanical Seal for Vertical Mixers is double, with a provision for coolant lines. Rotating head and stationary seat materials are selected for the specific application. A wear sleeve can be supplied through the seal which increases the effective shaft diameter. Shaft bearing support is installed close to seal and rigid alignment is maintained as is required by such seals.
Couplings, if flexible, used between motor and reducer input, are either of the rubber spider type of flexible steel grid type, in order to transfer full motor torque with a maximum misalignment of 3 degrees. Motors are shimmed for proper alignment. If rigid, as used between reducer output and impeller shaft, they are flanged and rabbeted for absolute alignment. Screws are recessed for safety and tapered split bushings are used for solid grip of keyed shafts. For larger mixers, both halves are pinned to support the shaft/impeller weight. all couplings are shielded, as are all moving parts.