CEM-System Liquid Delivery System with Vapour Control - Bronkhorst - #1

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> Introduction In a number of processes two or more components must be mixed together. In instances where it comprises a vapour of a liquid in a carrier gas, traditional Bubbler Systems and the more recent Vapour Source Controllers have been used. These devices, however, can often not handle sufficient quantities of liquid with a low vapour pressure, or perform in an imperfect way. Moreover, they cannot instantaneously provide vapour of a mixture of liquids with different vapour pressures. Bronkhorst High-Tech B.V. have therefore developed a unique patented system to realise Mass Flow Control of Vapours with an innovation: the CEM-Liquid Delivery System (LDS). It can be applied for atmospheric, pressurized and vacuum processes, vaporising liquid flows from 0,25 to 1200 g/h of water; for most other fluids the maximum capacity will even be higher. > Description At room temperature the liquid, for instance TEOS, HMDSO, CupraselectTM or water, is drawn from a container with an inert gas blanket, or membrane, and measured by a liquid mass flow meter type ì-FLOW or LIQUI-FLOW®. The required flow rate is controlled to the setpoint value by a control valve (C) forming an integral part of the patented liquid flow and carrier gas mixing valve (M). The then formed mixture is subsequently led into the evaporator to achieve total evaporation (E). This explains the abbreviation of CEM viz.: Control - Evaporation - Mixing, the 3 basic functions of the Liquid Delivery System. A complete system also incorporates a readout/control unit, including power supply, for operation of the CEM-system devices. > Features u accurately controlled gas/liquid mixture u fast response u high reproduceability u very stable vapour flow u flexible selection of gas/liquid ratio u lower working temperature than conventional systems u optional control by PC/PLC (RS232/fieldbus) CEM Liquid Delivery System with Vapour Control Liquid Flow Control Carrier Gas Control CEM Mixing chamber for liquid and carrier gas with heat exchanger for total evaporation Liquids (selection of some references) • ETOH • SnCl4 • TiCl4 • HMDSO • TCA • TMB • HMDSn • TEOS • Water • SiHCl3 • TIBA • Zn(C2H5)2 • SiH3Cl • Cupraselect™ • Organic compounds (such as Acetone, Alcohol, Butanol, Ethanol, Hexane, Methanol, etc.)