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Doc. no. : HTMF_Kor_2016, Rev. 0
Issued date : 2016. 11
HITROL Co., Ltd
1. Overview
HTMF-MF is a multipoint thermal dispersion–type gas flow meter. It enables measuring of gas
flow even at an installation location where flow distribution is not even based on multipoint gas
flow measurements. It is designed to have a microprocessor in the flow transmitter for high
accuracy and a self-diagnosis function. It is also designed such that it can measure flow
continuously by excluding abnormal sensors when some of the multipoint sensors of the flow
element become abnormal.
1.1
Operating Principles
Each flow element of this flow meter comprises a reference sensor and an active sensor, which
utilize a reference RTD and an active RTD, respectively. The reference sensor measures the fluid
temperature, while the active sensor having a heater measures temperatures higher than the
fluid temperature. When flow occurs in the fluid, the temperature measured by the active sensor
drops, which generates temperature difference, △T, between the reference sensor and the active
sensor. The flow element converts △T into resistance element △R from the reference RTD and
the active RTD, and sends △R to the flow transmitter. The flow transmitter calculates mass flow
and volume flow from △R and its relationship with gas mass.
1.2
Specifications
1.2.1
Flow measurement range: 0.1–100,000 SCFM (user specifiable).
1.2.2
Input power voltage: 110–130 VAC, 50–60 Hz, ±10%, 20 W maximum.
1.2.3
Number of sensor lines: 1–8 (user specifiable).
1.2.4
Measurable fluid: Gas (air, nitrogen, oxygen, carbon dioxide, methane, etc.).
1.2.5
Output signal level: 4–20 mA.
1.2.6
Operating pressure: Max 10 bar (higher pressure available upon user’s request).
1.2.7
Operating temperature: Flow element (
−
5℃ to 150 ℃), transmitter (0 to 60℃).
1.2.8
Accuracy: ±1.0% FS.
1.2.9
Repeatability: ±0.5% FS.
1.2.10
Response time: Max 1.0 sec.
1.2.11
Straight pipe size: Front end 15 D, rear end 10 D.
(minimum front end 5 D, minimum rear end 3 D)
