Gas cabinet

Photos of reconditioned gas cabinets

A gas cabinet is a metallic enclosure which is used to provide local exhaust ventilation system for virtually all of the gases used or generated in the Semiconductor, Solar, MEMS, NANO, Solar PV, Manufacturing and other advanced technologies.^[1]

The primary purpose of gas cabinets is to contain potential leaks in piping and fittings at the cylinder connection. The cabinet must be exhausted by a specifically designed fan and exhaust system. The cabinet exhaust system draws leaking hazardous gasses out of the cabinet. In the case of a flammable gas the cabinet will contain the flame for a period of time.^[2] One can use a newly reconditioned cabinet as well as non-reconditioned used gas cabinets depending on their requirements.^[3]

Features

There are a variety of gas cabinets available in the market in different gas cylinder configurations, such as 1, 2 and 3 bottle designs. They can be either new, used, or reconditioned. A gas cylinder cabinet can have many features depending on the specific gas. These features include gas sensor, sprinkler head, excess flow sensor, automatic operation with automatic purging and excess pressure sensor.

They should meet the Uniform Fire Code Specifications and the National Fire Protection Association. They need to adhere to the Compressed Gas Association and Semiconductor Equipment & Materials Institute codes. It is also important to know whether the cabinet is OSHA compliant. OSHA offers additional safety precautions involving the use of gas cabinets. In the absence of finite specifications or unknowns the user or designer should seek the assistance of an impartial consultant.

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Reconditioned gas cabinets can be more useful than non-reconditioned used gas cabinets because of the thorough process used in professionally reconditioning and testing to ensure all systems meet manufacturer’s specifications. Different types of gas cabinets can be used, depending on the gas type in the cylinder. Automatic gas cabinets with multiple sensors are useful and fulfill many other requirements.

A gas cabinet can also be manufactured specifically for a company's needs and at lower cost. It is required that a gas cabinet is used for fire safety for gas cylinders. The requirements vary by state. Many states have no advanced regulations for hazardous industrial gasses since there is little or no use of such gasses in that state. ^[5]

Types

The gas cabinets are categorized into four popular types based on the type of gas.^[6] The categories are:

Manual

These gas cabinets are used for inert, non-reactive and non-toxic gases. There are automatic gas cabinets also available and thus these cabinets are less useful when compared to automatic cabinets.

Fully automatic

These cabinets are available for corrosive, toxic and reactive gases. They provide safe and clean delivery of ultra-high purity gases. Such systems are designed to monitor a huge number of facility inputs and process sensors as per requirements.

Auto changeover

These gas cabinets are useful when uninterrupted gas flow is required. Auto changeover gas cabinets can be defined by mass or pressure inputs. There is software also available for multiple cylinder scales on each joint or bank. Purge down and purge up processes can also be performed without any interruption of connected cylinders.

Valve Ports

The port and valve specifications for gas cabinets and distribution systems are an important part of the selection process.

Valve Types

Gas cabinets may be distinguished by the types of valves used to control flow. Manual valves. Valves are manually adjusted or deployed via a control knob, lever, or other manual device. Solenoid valves. Valves are opened and closed via a solenoid magnet deployed by an electrical signal. Air pilot valves. Valves are deployed via a pneumatic signal.

Port Types

Ports are openings in the manifold or distribution system where the inlet and outlet connections are produced. Each opening is either an inlet (supply) port or an outlet port. The number of each corresponds to the requirements of the application. The quantity of supply ports specifies the number of independent fluid supplies that could be interfaced with the manifold or manifold system.

The number of outlet ports establishes the number of outlets in the system. This is frequently specified as number of ports or valves that are or can be attached to the manifold. For example, an 8-point manifold has 8 ports or valves. Ports are sized based roughly on tube or pipe size with some important choices. For industrial gases it is possible to purchase manifolds made of Stainless steel pipe or copper and brass although both these materials are giving way to Stainless steel tubing. (Note differences between Tubing and Pipe). Connection choices might be NPT, VCO, Flare or other types.

For gas service that is "Clean For Oxygen Service (CFOS)"  or for Ultra Pure service, manifolds and change over assemblies are typically made from 1/4" OD, 316 L, Electropolished tubing (the ID is Electropolished). The fittings used for ports and other connections are exclusively the "VCR" fitting. Training is needed to properly handle and install VCR connections using a variety of non-resuseable crushable metal gasket materials. Metal gaskets are essential in order to achieve high helium leak ratings.

Specifications

The specifications for a gas cabinet detail everything from gas flow rates to the physical size of the system.

Maximum pressure

Pressure describes the amount of force exerted on a system by the contained and pressurized gas. Most compressed gases will not exceed 2,000 to 2,640 pounds per square inch gage (psig), but some can reach pressures of 6,000 psig. The system's weakest point determines the pressure limit, so any parts weakened by heat, corrosion, or stress may potentially lower the maximum pressure of the system or cause the vessel to rupture. Many times this is at the point of welds.

Maximum flow

Flow rate details the maximum rate of flow of the gas through the operation, typically measured in standard cubic feet per minute (scfm).

Temperature range

Temperature range is the full mandated range of safe ambient or fluid operating temperatures, given in degrees Fahrenheit or degrees Celsius.

Dimensions

Size dimensions specify the physical size of the gas cabinet, distribution system, or its components. Cabinet size - Indicates the physical size of the gas cabinet or the body of the distribution system. Port/tube size - Indicates the physical size of the tubing or exhaust port connections in the system, typically given in inches based on a sizing standard such as National Pipe Thread (NPT). Sizing is important, as an undersized tube line will result in high pressure drops, while an oversized line will be unnecessarily expensive to install.

Materials

The materials used to construct the gas cabinet are an important part of proper system selection. The materials used for the casing and outer parts must have adequate structural strength, while the materials for the gas handling components must be compatible with the media, temperature requirements, and pressure ratings to prevent leakage, rupture, or contamination.

Aluminum

A light and fairly corrosion resistant metal which is most often anodized for increased corrosion and wear resistance. Aluminum is never used for tubing or fittings in modern industrial gas control & distribution systems since 316L stainless steel (optimum choice) is so available. Aluminum is not an ideal choice for purity. Aluminum in any form is never used for ultra pure industrial gas systems.

Copper

A soft, ductile metal with low hardness and excellent corrosion resistance. Copper is used commonly in tubes and pipes for its inertness and resistance to corrosion. Copper can be used for low air, oxygen and other inert non-critical gases such as medical CFOS systems. For ultra pure gasses 316L Stainless steel remains the optimum choice for many reasons.

Plastic

Any of numerous thermoplastic or thermosetting polymers of high molecular weight. Different grades (such as nylon, acetal, and polycarbonate) have varying properties, but most have strong chemical and corrosion resistance.

Steel

General purpose industrial metal with high physical strength and hardness. Steel is typically coated or finished to increase its corrosion resistance properties. Steel is used in the petroleum and metro-chem industries.

Stainless steel

316L Stainless steel became industry standard for fittings, piping and controls in gas cabinets and distribution systems in the early 1980s. The material is further improved by electropolishing to render wetted surfaces extremely impervious to the most reactive gasses creating a non-shedding surface. A large industry has grown around supplying these ultra-specialized components and materials.

References

↑ N.A. Downie (31 December 1996). Industrial Gases. Springer Science & Business Media. pp. 219–. ISBN 978-0-7514-0352-7.
↑ "Compressed Gas Safety". North Carolina State University. Retrieved 2015-02-21.
↑ "Toxic Gas Cabinets". Environment Health and Safety University of California,Berkley. Retrieved 2015-02-21.
↑ "OSHA Safety Precautions". USA Safety. Retrieved 2015-02-21.
↑ "Federal Gas Cabinet Opportunities". Fed Biz Opps. Retrieved 2015-02-21.
↑ "Gas Distribution Systems". Global Spec. Retrieved 2015-02-21.

Packaging

General topics	Active packaging Child-resistant packaging Disposable food packaging Food packaging Luxury packaging Modified atmosphere/modified humidity packaging Package pilferage Package testing Packaging engineering Pharmaceutical packaging Reusable packaging Shelf life Sustainable packaging Tamper-evident Tamper resistance Wrap rage

Containers	Aerosol Container Aluminium bottle Aluminum can Ampoule Antistatic bag Bag-in-box Bags and flexible containers Barrel Beer bottle Biodegradable bag Blister pack Boil-in-Bag Bottle Box Bulk box Carboy Carton Chub Clamshell Corrugated box design Crate Disposable cup Drum Envelope Flexible intermediate bulk container Foam food container Folding carton Growler Insulated shipping container Intermediate bulk container Jar Jerrycan Jug Juicebox Keg Multi-pack Oyster pail Packet (container) Padded mailer Pail Paper bag Paper sack Plastic bag Plastic bottle Popcorn bag Retort pouch Sachet Security bag Self-heating can Self-heating food packaging Shaker-style pantry box Shipping container Skin pack Spray bottle Tin can Tube Unit load Vial Wooden box

Materials and components	Adhesive Aluminium foil Bioplastic Biodegradable plastic BoPET Bubble wrap Bung Cellophane Closure Coated paper Coating Corrugated fiberboard Corrugated plastic Cushioning Desiccant Double seam Foam peanut Glass Hot-melt adhesive Kraft paper Label Linear low-density polyethylene Liquid packaging board Low-density polyethylene Metallised film Modified atmosphere Molded pulp Nonwoven fabric Overwrap Oxygen scavenger Packaging gas Pallet Paper Paper pallet Paperboard Plastic film Plastic pallet Plastic wrap Polyester Polyethylene Polypropylene Pressure-sensitive tape Screw cap Screw cap (wine) Security printing Security seal Shock detector Shock and vibration data logger Shrink wrap Slip sheet Staple (fastener) Strapping Stretch wrap Susceptor Tear tape Temperature data logger Time temperature indicator Tinplate Velostat

Processes	Aseptic processing Authentication Automatic identification and data capture Blow fill seal Blow molding Calendering Canning Coating Containerization Curtain Coating Die cutting Die forming (plastics) Electronic article surveillance Extrusion Extrusion coating Graphic design HACCP Hermetic seal Induction sealing Injection molding Laminating Laser cutting Molding Papermaking Plastic welding Plastics extrusion Printing Quality assurance Radio-frequency identification Roll slitting Shearing (manufacturing) Thermoforming Track and trace Vacuum forming Ultrasonic welding Vacuum packaging Verification and validation

Machinery	Barcode printer Barcode reader Bottling line Calender Can seamer Cartoning machine Case sealer Check weigher Conveyor system Extended core stretch wrapper Filler Heat gun Heat sealer Industrial robot Injection molding machine Label printer applicator Lineshaft roller conveyor Logistics automation Material handling equipment Mechanical brake stretch wrapper Multihead weigher Orbital stretch wrapping Palletizer Rotary wheel blow molding systems Shrink tunnel Staple gun Tape dispenser Turntable stretch wrapper Vertical form fill sealing machine

Environment, post-use	Biodegradation Environmental engineering Glass recycling Industrial ecology Life-cycle assessment Litter Paper recycling Plastic recycling Recycling Reusable packaging Reverse logistics Source reduction Sustainable packaging Waste management

Anesthesia (outline)

Types	General Sedation Twilight anesthesia Local Topical Intercostal nerve block Neuraxial blockade Spinal Epidural Dental Inferior alveolar nerve

Techniques	Airway management Anesthesia provision in the US Arterial catheter Bronchoscopy Capnography Dogliotti's principle Drug-induced amnesia Intraoperative neurophysiological monitoring Nerve block Penthrox inhaler Tracheal intubation

Scientific Principles	Blood–gas partition coefficient Concentration effect Fink effect Minimum alveolar concentration Second gas effect

Measurements	ASA physical status classification system Baricity Bispectral index Direct Fick method Entropy monitoring Fick principle Goldman index Guedel's classification Mallampati score Neuromuscular monitoring Thyromental distance

Instruments	Anaesthetic machine Anesthesia cart Boyle's machine Gas cylinder Laryngeal mask airway Laryngeal tube Medical monitor Odom's indicator Relative analgesia machine Vaporiser Double-lumen endotracheal tube Endobronchial blocker

Complications	Emergence delirium Allergic reactions Anesthesia awareness Local anesthetic toxicity Malignant hyperthermia Perioperative mortality Postanesthetic shivering Postoperative nausea and vomiting Postoperative residual curarization

Fields of study	Cardiothoracic Geriatric Oral sedation dentistry

Professions	Anesthesiologist Anesthesiologist assistant Nurse anesthetist Operating Department Practitioners Certified Anesthesia Technician Certified Anesthesia Technologist Anaesthetic technician

History	A.C.E. mixture Helsinki Declaration for Patient Safety in Anaesthesiology History of general anesthesia History of neuraxial anesthesia History of tracheal intubation

Organizations	American Association of Nurse Anesthetists American Society of Anesthesia Technologists & Technicians American Society of Anesthesiologists Anaesthesia Trauma and Critical Care Association of Anaesthetists of Great Britain and Ireland Association of Veterinary Anaesthetists Australian and New Zealand College of Anaesthetists Australian Society of Anaesthetists International Anesthesia Research Society

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