model S single tube flow metersmodel S single tube flow metersModel S single tube flow meters are similar to P meters in design, employing the same interchangeable flow tubes, valves, and accessories. Likewise they may be panel or bench mounted. The primary advantage of the S meter is convenience in applications, where frequent changing of tubes in meter cases is desired. An example is when several flow tubes are used in conjunction with a single meter case, or when because of the nature of the fluid, periodic cleaning necessitates disassembly.Aalborg’s exclusive TUBELOK™ design facilitates simple installation and replacement of tubes in mounting cases. As a result of the "non-rotating” adapter feature, glass flow tubes are prevented from turning during the tightening phase of the assembly procedure. Flow tubes for these variable area flow meters (rotameters) are available with two types of scales, suitable for different types of applications DIRECT READING SCALES Direct reading scales are indicating flow rates of liquids and gases,in engineering units such as [mL/min], standard cubic feet per hour [scfh] etc. Such scales are designed exclusively for a specific gas or liquid at a given set of pressure and temperature parameters, and are valid for the associated units of flow only. The convenience of direct reading scale designs should be weighed against the resultant limitations of applicability. Generally, direct reading scales are most suited to OEM applications. UNIVERSAL MILLIMETER (CORRELATED) SCALES Millimeter scales indicate the vertical position of the spherical float within the metering tube as the flow increases or decreases. It is necessary to use flow tables or graphs supplied, to correlate float referenced readings with actual volumetric flow rates. Alternatively the flow tables and graphs can be found using our online Flow-Tube Calibration Data Library by looking up your flow tube part number. The advantage of Universal type scales is the ability to utilize the use of a given flow meter for a great number of different fluids at diverse pressure and temperature conditions, generally preferred in applications in laboratories, etc. BUILT-IN VALVES Meters are available with built-in needle valves (CV™), high precision metering valves (MFV™) with “non-rising stems”, or with no valves. The higher cost of MFV™ valves is justified whenever high sensitivity control and resolution are desirable particularly in conjunction with metering tubes of very low flowrates. Generally, for gas metering it is recommended that valves are positioned at inlets (bottom) for liquids valves may be positioned either at inlets or outlets (top). For vacuum services, valves must be mounted at outlets. If unspecified at the time of ordering, meters will be shipped with valves mounted at the inlets.
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