ASME Vessels. Generally refers to pressure vessels and alloy high-pressure vessels, the design of which conforms to specifications, materials, and requirements of pressure vessel code adopted by the American Society of Mechanical Engineers. A pressure vessel is a closed container designed to hold gases or liquids at a pressure that is different from the ambient pressure. These vessels, usually cylindrical, have a body with end caps, called heads, fitted to the ends of the body. Pressure vessels are designed to operate safely at a specific pressure and temperature, referred to as the “Design Pressure” and “Design Temperature.”
Things to Consider: Volume of gas or liquid, Design and construction according to ASME code, Material, Design pressure, Design temperature, In and out connections, Dimensions, Weight, Repair history documentation if vessel is used equipment, Warranty.
Cryogenics Vessels. These vessels are designed to handle liquified gases, such as liquid nitrogen and liquid helium, at the lowest attainable temperatures. Some specialty vessels are designed to store cryogenic fuels, such as hydrogen and oxygen. Most cryogenic vessels are made from carbon or stainless steel, and are designed in accordance with ASME specifications.
Things to Consider: Height with lid, Diameter, Neck diameter, Liquid nitrogen capacity vapor phase, Average static liquid nitrogen consumption rate vapor phase (liters/day), Static holding time vapor phase (days), System capacity (cryovials), Racks included with vessel, Boxes per rack, Box capacity, Box dimensions, Boxes needed for system, Liquid nitrogen level alarm, Autofill controller, Electrical requirements, Shipping weight, Warranty.
Fiberglass Vessels. These vessels can be either pressure vessels designed to operate safely at a specific pressures and temperatures, or non-pressure vessels designed for use in gravity controlled and low-pressure systems. Fiberglass vessels are often chosen for corrosive process systems. They can withstand higher temperatures and pressures than ordinary thermoplastic materials. Their corrosion and chemical resistance makes them well-suited for general chemical processing applications. Fiberglass vessels can be used in a wide variety of corrosion resistant conditions, have low thermal conductivity, and low long-term maintenance costs.
Things to Consider: Solution being stored or processed, Solution temperature, Capacity, Vacuum or pressure, Wind load, Seismic forces, Corrosion allowances, Loads imposed by agitation or platforms, Lift and hold down lugs, Nozzle flanges, Corrosion resistance, Dual laminate construction with thermoplastic liner for extremely aggressive liquids, Maximum temperature for solution in tank typically 150-170F for isophthalic polyesters and 200-220F for vinyl esters, Required wall thickness calculated using ASME RTP-1 guidelines,Vessel geometry, Liquid specific gravity, Wall thickness losses due to erosion, Placement of tank above or below ground affects internal and external pressures, External stiffening ribs, Dual containment requirements, Leak detection systems, Pigmented topcoat or natural resin coloration, Shipping restrictions for oversized vessels, Prefabricated vessel sections option, Dimensions, Weight, Warranty.
Field Fab Vessels. These are vessels, or storage tanks, that have been specially designed to be quickly erected on location in the field, instead of being fabricated in a factory and shipped to location. Field fabricated vessels include structures such as: stainless steel tanks, pressure vessels, evaporators, columns and equipment for use in the dairy, food, grain, ethanol, chemical, beverage, wine and brewing industries. Experienced providers can field fabricate tanks with capacities of up to 500,000 gallons.
Things to Consider: Foundation loading (static and dynamic loads), Soils report, Storage capacity, Modular construction, Field-weld decks and hoppers, Code requirements including radiograph examination of welds, Local building codes, Transportation logistics, Local fabrication skills availability, Warranty.
Glass Lined Vessels: Glass lining is a form of porcelain enamel, much like the material applied to bath tubs and sinks. It forms a permanent chemical and physical bond with the metal surface. The finished surface is extremely smooth and very hard, making glass-lined vessels ideal for handling chemicals that tend to adhere to the inside of bare metal vessels. The glass lining is non-permeable; resistant to corrosion, abrasion, high temperatures, and thermal shock; and has a wide pH range.
Things to Consider: Volume of liquid, Maximum allowed working pressure rating at a specified temperature, Top cover pressure rating, Manway hatch option, Dimensions, Repair history documentation if vessel is used equipment, Weight, Warranty.
Kettles. These are top loaded vessels designed to apply radiant heat to the vessel’s external surface. Some, supplied with pressure covers, can be used at high pressure. Heating elements radiate uniform heat directly to the outer surface walls of the vessel from which it transfers to the material being heated. Industrial kettles, usually made from welded carbon steel, stainless steel, or copper, and jacketed with high-grade insulation, can support temperatures up to 650°F. All are supplied with appropriate control instrumentation, and some are provided with motor-driven agitators or scraper blades.
Things to Consider: Capacity (gallons), Material (typically stainless steel), Heating method, Agitator assembly type, Reinforced rim, Pouring lip, Tilt handle, Faucet, Electrical control box, Etch markings for measuring quantity of fill, Polished interior (specify emery grit finish), Exterior finish for ease of cleaning and bright appearance, ASME code, UL listing, Maximum working pressure, Sanitary requirements, NSF listing, Kettle temperature range, Power requirement, Rust inhibitors, Thermostat, Built in contactor, Pressure gauge, Front mounted water sight glass, Heating indicator lamp, Agitator on-off and variable speed control switch, Safety tilt cut-off, Pressure relief valve, High limit pressure switch, Low water cut off, 24V control system, Agitator safety tilt cut off, Thermostatically controlled, Automatic shut off when desired temperature is reached, Automatic turn on when product temperature falls below desired setting, One person tilt capability (even when kettle is full to capacity), Hot & cold faucets, Basket insert option, Lift off cover option, Holder for lift off cover option, Stand mounting option, Kettle brush kit, Dimensions, Weight, Installation requirements, Warranty.
Mechanical Vessels: Expansion Tanks & Air Receivers. An expansion tank is a small tank used in closed water heating systems and domestic hot water systems to absorb excess water pressure caused by thermal expansion or water hammer. An air receiver delivers or stores short-term demand that either exceeds or is less than an air-compressor’s capacity.
Things to Consider: Expansion tank: Tank volume and acceptance volume requirements, Water heater capacity, Water supply pressure, starting and ending water temperatures, Maximum pressure setting of relief valve, Multiple tanks option, Dimensions, Weight, Warranty; Air receiver: Compliance with CSA B51, Pressure relief valve quality, Lubrication oil specifications, Expiry date (if present) indicates receiver is exempted from CSA B51 but must be discarded immediately after expiry date, Dimensions, Weight, Warranty.
Polypropylene Vessels. These vessels can be either pressure vessels designed to operate safely at specific pressures and temperatures, or non-pressure vessels designed for use in gravity controlled and low-pressure systems. These vessels are lighter than those made from other materials. Their smooth inner walls resist the formation of deposits. Though they do not have the strength of metal vessels, they have enough tensile and burst strength to withstand operating pressures encountered in most service conditions. They can withstand external shocks that could cause failure in more brittle materials. They are resistant to water, nearly all acids, alkalis, salt solutions, and other corrosive liquids and gases.
Things to Consider: Volume of liquid, Gasketed lip for sealing cover, Reinforcement ribs around perimeter of tank for additional wall support, Specific gravity of fluids, Safety factor, Ultimate load safety factor from destructive burst testing, Water column rating with and without positive ventilation, Reinforced and gasketed top, Support for mounted equipment, Support for one 200 lb person without significant deflection, Dimensions, Weight, Repair history documentation if vessel is used equipment, Warranty.