4  SPECIFIC PRINCIPLES TO COVER EXCEPTIONS AND ADDITIONS TO THE DESIGN, CONSTRUCTION AND CLEANING OF ALL BAKERY EQUIPMENT, AS DEFINED IN SECTION 3.

4.6  DESIGN REQUIREMENTS FOR HORIZONTAL AND VERTICAL MIXERS

4.6.1 Specific Design Requirements for Horizontal Mixers

4.6.1.1 Agitators and agitator shaft assemblies shall be designed and constructed to permit all surfaces to be effectively cleaned

4.6.1.2. Where machine faces are joined, the joints shall be made smooth, and shall be pressure-tight over the entire face of the joint. Fillers or bonding compounds shall not be used in the product zone.

4.6.1.3 Agitator ends shall have surfaces of minimum area immediately adjacent to the bowl ends and no longer than necessary to ensure proper incorporation of all ingredients into the mix.

4.6.1.4 Shaft seal rings shall be readily accessible and readily removable or retractable to permit cleaning of all product zone surfaces thereon, including the face of the agitator hub.

4.6.1.5 Surfaces on the shaft passing through the seals shall meet all product zone criteria.

4.6.1.6 Agitator shaft seals shall be provided with convenient means for adjustment to prevent leakage, and shall have complete drainage to the exterior to avoid accumulations of material in the event that leakage does occur.

4.6.1.7 Shaft seals shall be self-lubricating.

4.6.1.8 Openings provided for the addition of ingredients shall be of adequate size to prevent spillage, and shall be flanged outward 3/8 inch (10mm). The door or cover of the opening shall fit tightly when shut. Hinges shall be of the simple take-apart type, and shall be so constructed that when taken apart no cracks or crevices exist.

4.6.1.9 The diameter of the shaft opening in the bowl ends shall be at least 1½ inches (40mm) larger than the diameter of the shaft.

4.6.1.10 A minimum distance of 4 inches (100 mm) shall be provided between the mixer bowl head and the end frame housing.

4.6.1.11 The flour inlet gate assembly shall be readily removable and all component parts shall be removable.

4.6.1.12 Liquid ingredient inlets shall be of sanitary construction, and shall be no longer than twice their diameter, or shall be removable. Inlets shall not project into the bowl, and should be located in the cover or upper portion of the bowl. Check flaps shall not be used.

4.6.1.13 Liquid ingredient inlet pipes, valves and fittings shall be of sanitary take-apart type, and shall be removable back to the point where the line is normally continuously filled. Terminal lengths of such pipe lines shall be self-draining.

4.6.1.14 Potable water inlet lines shall terminate not less than 1 inch (25mm) or twice the inlet pipe diameter, whichever is greater, above the overflow level of the bowl.

4.6.1.15 Stationary mixer bowls shall drain completely. Close-coupled sanitary drain valves, which are accessible or removable, shall be provided.

4.6.1.16 Frame access openings shall permit easy access to all internal surfaces. Hinges shall be of the simple take-apart type, and shall be so constructed that when taken apart no cracks or crevices exist.

4.6.1.17 Closures for access openings to hollow spaces within the frame shall be designed and constructed to prevent the entry of water. Hinges and latches shall be of the simple take-apart type, and shall be so constructed that when taken apart no cracks or crevices exist.

4.6.1.18 Convenient access for cleaning outside surfaces of movable or pivoted mixer bowls shall be provided.

4.6.1.19 Gaskets between the bowl and cover shall be readily removable.

4.6.1.20 Vacuum mixers shall be equipped with a readily removable sanitary check valve to prevent the return of materials from the vacuum line to the mixing chamber. Vacuum lines between the check valve and trap shall be readily removable.

4.6.1.21 Traps in the vacuum lines shall be readily removable.

4.6.1.22 Vacuum relief valves shall be readily removable.

4.6.1.23 Electrical control cabinets mounted on the exterior of the mixer shall be watertight and sealed to the supporting member, or spaced sufficiently away from the member to permit cleaning of all surfaces. A minimum of ¾ inch (20mm) between the control cabinet and the supporting member shall be provided.

4.6.1.24 Bearings used to support rotating agitator roller bars may be fabricated from a nickel bronze alloy.

4.6.1.25 Bearing caps and split hub agitators may be secured with acorn, cap, or hex head bolts.

4.6.2 Specific Design Requirements for Vertical Mixers

4.6.2.1 Part numbers where required on beaters, shall be stamped on the top end surface of the shank or sleeve

4.6.2.2 Permanently joined metal surfaces with a total included internal angle less than 135 degrees on agitators shall have a radius of not less than 1/8 inch (3mm) tangential to both adjacent surfaces.

4.6.2.3 The requirements of a radius shall not apply to points of wire attachment and support on wire whip agitators. However, the space between wires at points of attachment shall not be less than two diameters of the wire, but in no case shall this space be less than ¼ inch (6mm).

4.6.2.4 Wire whip agitators shall be constructed so that all wires are held rigidly at the point of attachment and all other contact between wires shall be separable.

4.6.2.5 Scrapers shall be readily removable from the agitator.

4.6.2.6 Shaft seal rings of agitators passing through bowl or cover shall be readily accessible and readily removable or retractable to permit cleaning of all product zone surfaces thereon, including the face of the agitator hub. The diameter of the shaft opening in the mixer head shall be at least 1½ inches (40mm) larger than the diameter of the shaft.

4.6.2.7 Surfaces on the agitator shaft passing through the seals shall meet all product zone criteria.

4.6.2.8 Agitator shaft seals shall be provided with convenient means for adjustment to prevent leakage, and shall have complete drainage to the exterior to avoid accumulations of foreign matter in the event that leakage does occur.

4.6.2.9 Agitator shaft seals shall be self-lubricating.

4.6.2.10 Potable water inlet lines shall terminate not less than 1 inch (25mm) or twice the inlet pipe diameter, whichever is greater, above the overflow level of the bowl.

4.6.2.11 Stationary mixer bowls shall drain completely. Close-coupled sanitary drain valves, which are accessible or removable, shall be provided.

4.6.2.12 Bowl top rims shall be of one-piece construction, or shall be sealed to the mixer bowl.

4.6.2.13 All attachments to bowl exteriors shall be sealed.

4.6.2.14 Frame access openings shall permit easy access to all internal surfaces. Hinges shall be of the simple take-apart type, and shall be constructed that when taken apart no cracks or crevices exist.

4.6.2.15 Transmissions shall be adequately housed so that no leakage of lubricant occurs.

4.6.2.16 Covers for mixer bowls shall be constructed so that drainage from the exterior of the cover shall be to the outside of the bowl in all cover bowl positions.

4.6.2.17 Gaskets between the bowl and cover shall be readily removable.

4.6.2.18 Vacuum mixers shall be equipped with a readily removable sanitary check valve to prevent the return of materials from the vacuum line to the mixing chamber. Vacuum lines between the check valve and trap shall be readily removable.

4.6.2.19 Traps in the vacuum lines shall be readily removable.

4.6.2.20 Vacuum relief valves shall be readily removable.

4.6.2.21 Motors and accessory equipment sealed within the mixer housing shall be exempt from the requirements of Section 4.28.