Thermal Mass Flowmeter

Brief Introduction

Thermal Mass Flowmeter latest technology specially designed for air and N2 applications. It has more compact design, which means smaller enclosure and thinner insertion tube probe. Due to its small diameter insertion probe and shorter high-sensitive sensor, it can be used on pipes from DN25~DN500, or even larger pipe. In some higher pressure applications, it can be installed / removed without stopping the fluid, as the pipe is thinner, field engineers will be able to insert the meter to pipe very easily. Also, to fulfill the cost-saving demand in compressed air and N2 applications, will be the most cost-effect model in the market. Thermal Mass Flowmeter measures the gas mass flow base on thermal diffusion theory. It has two RTDs as its sensors, one of which sense the velocity of the gas flow (RH) and the other one will detect the temperature shift of the gas flow (RMG) . When the two RTD are in the gas flow ,the RH will be heated while the RMG will sense the temperature changing of the gas flow. More heat will be taken away as the velocity of the gas flow increasing ,so the temperature on RH will decline.According to King’s law, the heating power P, the temperature difference ΔT (TRH-TRMG) and the mass flow rate are mathematical related . P/△T=K1+K2 f(Q)K3 , the K1、K2、K3 are constants related to the properties of the gas. Series Thermal mass flow meter is designed base on constant power measuring method, thus the RTD is heated in a consistent power and will be more durable and stable. That is why flow meter has less problem of zero-off which may caused by a function failure of RTD due to over-heated in long term.

 Application

This application are specially designed for air and N2 applications, such as compressed air, venting air, aeration , process protection N2, combustion air etc.

Picture: LCD displayer of thermal mass flow meter

Product features

1) 100:1 turn down ratio in 5 ranges: 0.3~30 Nm/s, 0.6～60 Nm/s, 0.9~90Nm/s , 1.2~120Nm/s, 1.5~150Nm/s

2) Large LCD screen with dual-line display

3) Low cost economical model.

4) Online data logger optional

5) No pressure loss, suitable for pipe in any shape with known sectional area

6) For the insertion type, Quick and Fast Installiation.

7) Measure the mass flow and standard flow directly.

9) High accuracy data acquisition circuit to ensure outstanding repeatability and accuracy of the flow meter.

9) Electrical structure of total isolation to ensure a excellent EMC properties and avoid the interference from outside

10) High efficiency design of power supply, the total power consumption is only 100 mA @ 12 V DC

11) 12 V DC Power Supply.

12) Self-protection design of Zener safety barrier inside

 Process connection

The  Thermal Flow meter has two different installation types, one is insertion and the other is in-line type.

The insertion type can be installed and maintained on line. To install it, you have to weld and install a socket with screw thread outside on the pipe and install a 1 inch or 1/2 inch ball valve on the base. Then drill a hole of 13mm (or 22mm) diameter on the pipe with a special tool and install the flow meter on the pipe through the hole. The position and depth of how the sensor is fixed have already been set before delivery.

The fitting in diameter of pipe for insertion type: DN25～900mm (Please make sure to let us know if you need it for larger diameter)

The In-line type is delivered along with a pipe which has a same inner diameter as the pipe in field. Is should be installed through flange or screw thread. T.he flanges meet GB/T9119-2000 standard（or ANSI B16.5 or DIN or JIS standard）. The in-line type can fit in pipe with diameter from DN15mm to DN300mm. Or customer can simply choose to use a 3-way pipe to replace the flanged body
Sensor is made in 304 stainless steel and the pipe is made in 304 or 316 stainless steel. If users need them to be made in different material, please us know before order confirmed.

Each and every thermal mass flow meter will be calibrated on a sonic nozzle calibration system, which is the most accurate air calibration system (0.05%) in the world. The flow meter will be calibrated at 19 velocity points and verified at 8 velocity points. All meter factors are input to the meter automatically and checked by experienced engineers. We ensure you that every flow meter from  have been well cared for best accuracy, repeatability and durability.

Sonic nozzle calibration system

Specification

Remark:

The insertion probe of meter has 2 diameters, which are 11mm with 1/2” NPT and 19mm with 1” NPT.

 When pipe line is over DN400 or flow velocity is higher than 90Nm/s, will use 19mm probe.

Model Selection

Other ordering information

Measurement range

Standard: 0.6~60 Nm/s

Option 1: 0.3~30 Nm/s

Option 2: 0.9~90 Nm/s

Option 3: 1.2~120 Nm/s

Option 4: 1.5~150 Nm/s

Standard Volume flow rate range in popular sizes