Table of Contents
Advertisement
Introduction
January 2023
Figure 1-8: Optional local display and glass endcap
The Rosemount 3812 Liquid Ultrasonic Flow Meter is a two-path (four
transducers) in-line meter designed to measure the difference in signal transit
time with and against the flow across one or more measurement path(s). A signal
transmitted in the flow direction travels faster than one transmitted against the
flow direction. Each measurement path is defined by a transducer pair in which
each transducer alternately acts as transmitter and receiver. The meter uses
transit time measurements and transducer location information to calculate the
mean velocity.
Computer simulations of various velocity profiles demonstrate that multiple
measurement paths provide an optimum solution for measuring asymmetric
flow. The Rosemount 3812 Liquid Ultrasonic Flow Meter utilizes two cross-bore,
parallel-plane measurement paths, offers a high degree of repeatability, bi-
directional measurement and superior low-flow capabilities without the
compromises associated with conventional technologies.
The Rosemount 3812 Liquid Ultrasonic Flow Meter's U.L. safety listing is
accomplished through the combination of an explosion-proof Transmitter
Electronics Enclosure that houses the CPU Module, Power Supply board, I.S.
Barrier board, Backplane board and optional LCD Display board.
Note
The optional LCD Display requires firmware v1.04 and Uboot version, January 31,
2013.
The Base Electronics Enclosure is intrinsically safe and houses the Acquisition
Module, the acquisition cable and wiring. The Intrinsically safe transducers and
cable assemblies are designed for Class 1, Division 1, Groups C and D areas
without need of further protection when installed in accordance with the field
wiring diagram (refer to Rosemount drawing DMC-004936, see
Drawings
14
and
Safety
conditions).
Installation manual
00825-0100-3812
Engineering
Rosemount 3812 Liquid Ultrasonic Flow Meter
Advertisement
Table of Contents
