In a number of processes two or more components must be mixed together. In instances where it comprises a vapor of a liquid in a carrier gas, traditional Bubbler Systems and the more recent Vapor Source Controllers have been used. These devices, however, can often not handle sufficient quantities of liquid with a low vapor pressure, or perform in an imperfect way. Moreover, they cannot instantaneously provide vapor of a mixture of liquids with different vapor pressures.
Bronkhorst® have therefore developed a unique patented system to realize Mass Flow Control of Vapors with an innovation: the CEM-Liquid Delivery System (LDS). It can be applied for atmospheric, pressurized and vacuum processes, vaporizing liquid flows from 0.25 to 1200 g/h of water; for most other fluids the maximum capacity will even be higher.
At room temperature the liquid, for instance TEOS, HMDSO, Cupraselect™ or water, is drawn from a container with an inert gas blanket, or membrane, and measured by a liquid mass flow meter type μ-FLOW, LIQUI-FLOW™ or mini CORI-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
> accurately controlled gas/liquid mixture
> fast response
> high reproducibility
> very stable vapor flow
> flexible selection of gas/liquid ratio
> lower working temperature than conventional systems
> optional control by PC/PLC (RS232/fieldbus)
Liquids (selection of some for reference)
* 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.)
Challenged by their outdated recipe mixing systems, budgetary constraints and a turbulent economy, a leading European candy manufacturer, who depends on accuracy and repeatability to maintain the quality of product, sought out Bronkhorst Cori-Tech to help streamline and improve their processes and cut costs. Bronkhorst engineers identified current system weak points and recommended a CORI-FILL™ solution.
The flow controller's primary function is the dosing of three critical ingredients of the chewy treats; the aroma (fragrance), the flavor, and the color. By communicating directly with a supervisory automation and control system, the CORI-FLOW™ instruments are provided the precise dosing requirements for a particular recipe. The compact design of the Bronkhorst Cori-Tech instruments, where the Coriolis meter and controlling shut-off valve are mounted in one compact unit, was a key factor in selecting the Bronkhorst solution as separation of the meter and the control valve creates dead volume which can lead to inaccuracy, erratic results, and inconsistent quality.
