ValuMass Series 400 VAL Inline Flow Meters

The ValuMass Series 400 VAL inline flow meters are rugged, cleanable, thermal mass flow sensors. Our VALGEN-RD flow meters consist of a sensor assembly which utilizes two RTD (Resistance Temperature Detector) sensing elements. The sensors are constructed of reference grade platinum, ceramic, glass, and stainless steel. Two platinum resistance sensors position upon a ceramic substrate and then they receive a thin glass coating. The assembly then slips into a stainless-steel sheath for corrosion and abrasion resistance.

The sensor assembly is large, rugged, and relatively insensitive to dirt buildup. During operation, the temperature sensor constantly measures the ambient temperature of the gas. It also maintains a reference resistance on one side of a bridge circuit. The temperature sensor and bridge circuitry forces the second sensor through self-heating to a constant temperature above that of the gas stream. The bridge maintains the overheat temperature and counterbalances the temperature effects through proprietary temperature compensation techniques.

Municipal and Industrial Inline Flow Meters with Thermal Mass Flow Sensors

Our flow meters provide accurate, consistent, and rapid real-time flow measurement with a sensor that is both temperature and pressure corrective. Each flow meter is also calibrated using standards traceable to the National Institute of Standards and Technology (NIST).

• accuracy: ± 1% of reading + 0.5% of full scale + GTC
• repeatability: ± 0.2% of full scale
• sensor response time: 1 second to 63% of final value
• gas temperature coefficient (GTC): 0.02% full scale/˚C
• gas pressure effect: negligible over ± 50% of factory calibration pressure

ValuMass Series 400 VAL Inline Flow Meters

These thermal mass flow inline flow meters include a flow section that matches the user’s flow conduit. It then plumbs directly into the process line. The sensing elements mount directly in the flow section for exposure to the process gas. Our inline style thermal mass flow meters are available in sizes from 1/4″ pipe through 2″ pipe. The 3.5″ long flow sections also have MNPT ends as standard for easy mounting in the process line. You can contact us to inquire about pipe sizes over 2″.

Integral style thermal mass inline flow meters contain all the electrical components and connections within one enclosure. Furthermore, this enclosure offers a rating for hazardous environments. The enclosure mounts directly to the inline flow section or to the insertion probe assembly at the point of measurement. The enclosure includes all the electrical connections as well as the linearizing electronics and the display assembly. Each VAL Series 400 aluminum enclosure includes a powder-coat-painted die-cast base and lid with a seal. The ratings available for the enclosure are: IP66, NEMA 1, 2, 4, 4X.

EPI Thermal Mass Flow Meters

Thermal mass flow meters use the principle of convective heat transfer to directly measure mass flow. EPI’s proprietary thermal mass flow sensors use two ratiometric, reference-grade platinum Resistance Temperature Detectors (RTDs). The platinum sensing element wire is in a 316 Stainless Steel sheath or, if necessary, a Hastelloy C sheath.

Our microcontroller smart sensor technology preferentially heats one RTD. Then the other RTD acts as the temperature reference. First, the process gas flow dissipates heat from the first RTD. This causes an increase in the power necessary to maintain a balance between the RTDs. This increase directly relates to the gas molecular rate of flow. Our sensors are temperature also compensated for a wide process gas temperature range and insensitive to pressure changes. Therefore, the output signal is a true mass flow rate signal.