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APPLICATIONThe Thermco 3 gas mixer is designed to mix three nonflammable and non-corrosive
gases. A constant mixture ratio is maintained between the three
gases from shutoff to full flow conditions. The 3 gas mixing system
is normally used with a process where the supply gases are drawn
from bulk sources and the mixture is produced on site to supply
a process by a pipeline. The system is designed for applications
that require a very reliable production of mixed gas on a continuous
basis such as shield gases for welding.
Accuracy: ± 5% of the minor component for minor components larger
than 7.0%; ± 0.35% of the minor component absolute for components
from 1.0 to 7.0%. For components less than 1.0% consult the factory. Ambient Operating Temperature Limits: 32º - 100ºF (0º - 38º C) Supply Gas Pressures: 100-125 PSIG (6.9 - 8.6 BARG) All Models Mixed Gas Pressure Supplied by Mixer: 10-50 PSIG (0.7 - 3.4 BARG) All Models Supply, Mixed Gas Connection: ½" NPT female all ports for Models 8610, 8615, 1" NPT female all ports for Models 8110, 8115, 8210, 8215. Surge Tank: 5 gallon, Models 8610, 8615; 30 gallon, Models 8110, 8115; 60 gallon, Models 8210, 8215. All surge tanks are ASME coded and CRN registered with a pressure relief valve. Power Requirements: 115 VAC, 50/60 Hz, 0.5 amp. Acceptable voltage range 102-120 VAC. Available on Request, 220 VAC, 50/60 Hz, 0.25 amp. Acceptable voltage range 204-240 VAC.
Dimensions: Models 8610, 8615: 31.6" (81cm) height, 20.6" (52 cm) width, 10.3"
(26 cm) depth. Mounting: Models 8610, 8615 - wall or bench mounted OPTIONAL PRESSURE ALARM SYSTEM A pressure alarm system is available to alert personnel of low input gas pressure. When one of the input gas pressures falls too low to create an accurate mixture, a light specific to the low-pressure gas is illuminated on the front door, and a horn on the enclosure sounds. The operator can silence the horn with a horn silence button on the the front door. This alarm will help prevent the creation of an improper mixture if one gas source is exhausted, or low input pressure is caused by some other reason. |
FEATURES
PRINCIPLES OF OPERATIONThe gases to be mixed are supplied from bulk storage system to the gas mixer. Normally the required pressure will be between 100 and 125 PSIG. Within the gas mixer these gas streams are regulated to the same pressure. Downstream of the gas regulators, the major gas flows through a fixed orifice and the two minor gas flow through fine metering valves. After passing through these devices, the three gas streams are combined and pass into a surge tank. Once the pressure in the surge tank reaches the upper set point on the pressure switch, the gas supplies are automatically shutoff with a solenoid valve. As mixed gas is required, the pressure in the surge tank falls until it reaches the lower set point of the pressure switch. At this point the gas supplies are turned on and the cycle repeats. TYPICAL INSTALLATION 
CHANGING THE GAS MIXTURE The gas mixture proportion is set at the factory per the customer request. Since the gas mixer is designed with a fixed orifice for the major gas and metering valves for the two minor gases, the proportion can be changed by the user. If the user desires to make a change, the user can adjust the metering valves in the gas mixer to create a new proportion, but the user must use a gas analyzer to measure the resulting mixture. For information concerning the range of adjustability, please contact the Thermco factory. SPECIAL REQUIREMENTS Gas mixers utilizing the basic design can be engineered for special applications. These include applications, which require higher or lower pressures or the addition of special switches or gas analyzers. Consult Thermco for details on these special requirements. THE THERMCO QUALITY ASSURANCE PROGRAM All gas mixers are tested for a minimum of 24 hours on the actual process gases at the ordered pressure conditions. Each gas mixer is precisely tested with gas analyzers to verify the mixture accuracy. Thermco has available gas chromatography, infrared, paramagnetic and electrochemical types of gas analyzers to test the mixture. A copy of the inspection report is available on request. DOCUMENTATION A comprehensive instruction manual is provided with each gas mixer. A specific data sheet is made for each order, which specifies pressure settings, orifice sizes, critical components and recommended spare parts. A copy of the manual is kept on file at Thermco to assist in service help. WARNING Improper use of this product can cause death, serious injury, or property damage. Personnel dealing with this equipment should read and understand warning labels and instruction manuals provided by Thermco. Only personnel familiar with industrial gases should attempt to install or service this equipment. Gases from high-pressure cylinders must be reduced to the specified pressure before entering the gas mixing system to prevent the possibility of equipment damage and personal injury. NOTICE In the interest of continued product development, Thermco reserves the right to change design features without prior notice. Sale of this equipment is under the terms of the Thermco warranty available upon request. ORDERING INFORMATION Orders may be placed directly with Thermco or through many local gas suppliers. | |||||||||||||||||||||||||||||||||||||||||||||||
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