Dynasonics TFXM Series Ultrasonic Multi-Channel Flow Meter - Manual (Page 101)

Description: Installation and Operation Manual Addendum
Series TFX Heat Flow Meter
Origin Date: 02/10/00
Revision: none Revision date: none Page 1 of 3
Addendum — Heat Flow
Dynasonics Series TFX Heat Flow
General
The TFX flowmeter with the optional heat flow module installed is designed to meas-
ure the rate and quantity of heat delivered to a given building, area or heat exchanger.
The instrument measures the volumetric flow rate of the heat exchanger liquid (water,
water/glycol mixture, brine, etc.), the temperature at the inlet pipe and the temperature
at the outlet pipe. Heat delivery is calculated by the following equation:
Rate of heat delivery = Q*(Tin – Tout)*c
Where
Q
= volumetric flow rate
Tin = temperature at the inlet
Tout = temperature at the outlet
c = specific heat of the liquid
The RTD module installed in the TFX measures the differential temperature of two
1000-ohm three-wire platinum RTDs. The three-wire configuration allows the tem-
perature sensors to be located several hundred feet away from the TFX meter without
influencing system accuracy or stability. The TFX transit time flow meter can also tol-
erate large distances between the flow measurement transducers and the electronic
instrument.
The RTDs included with the TFX heat delivered flowmeter have been factory cali-
brated and are marked with an identification as to which terminal, #1 or #2, the RTD
has been calibrated. The RTDs are 1000-ohm platinum and are designed to be
mounted on the exterior surface of the pipe. The RTDs are rated for a temperature
range of –50 to +130 C.
Installation
1. Follow the instructions outlined in the standard TFX manual for proper installation
of the flow measurement transducers. After installation, verify that the Signal
Strength is greater than 4-5% and, if possible, perform a Zero flow calibration on
the pipe. Please note that all readings require a full pipe of liquid.
2. Select areas on the inlet and outlet pipes where the RTDs will be mounted. Re-
move or peel back the insulation all the way around the pipe in the installation
area. Clean an area slightly larger than the RTD down to bare metal on the pipe.