A 40 KL milk storage silo shall be a vertical, cylindrical, insulated and refrigerated sanitary stainless-steel tank having a nominal storage capacity of 40,000 litres, suitable for storage of raw or pasteurized milk at approximately 2–4°C. The product-contact parts shall be manufactured from SS 304/304L stainless steel or SS 316L where specifically required, with smooth hygienic internal surfaces, typically Ra ≤ 0.8 µm, fully welded and polished to eliminate crevices and dead legs. The silo shall be provided with suitable thermal insulation, preferably 75–100 mm PU/PIR insulation, with an SS external cladding/jacket. The tank shall have a sanitary top section with manway, filtered air vent, vacuum/pressure protection, CIP spray device/rotary jet head and top-entry sanitary agitator. The bottom shall be suitably sloped or dished to ensure complete drainage and shall be provided with a sanitary milk outlet. The silo shall include hygienic milk inlet and outlet connections, CIP supply and return connections, sampling valve, sanitary butterfly/seat valves, temperature sensor, level transmitter, high- and low-level protection, and suitable load-cell weighing arrangement if required. The cooling system shall be designed to maintain the milk at the specified storage temperature and shall be sized according to milk inlet temperature, required cooling time, ambient temperature, insulation performance and filling rate. The agitator shall provide uniform milk circulation without excessive foaming and shall be suitable for continuous or intermittent operation. All gaskets shall be food-grade EPDM, silicone or PTFE and compatible with the specified CIP chemicals. The silo shall be mounted on a suitable structural support with access ladder and platform where required. All product-contact welding shall be hygienic TIG/orbital welding as applicable, and the complete system shall be suitable for automatic CIP using caustic, acid and sanitizing solutions. The supplier shall provide GA and fabrication drawings, material certificates, welding and inspection records, pressure/vacuum test certificates, surface-finish certificates, FAT/SAT documentation, electrical drawings, operation and maintenance manuals, and all necessary commissioning documentation. The design and fabrication shall comply with applicable 3-A sanitary standards, EHEDG hygienic-design principles and relevant Indian/international standards, with final tank dimensions, shell thickness, refrigeration capacity, agitator power, nozzle sizes and structural design to be confirmed by the manufacturer based on process and site conditions.
