SeoJin Instech, Seojin , Seojin Instech Vietnam

ST-600 Float Type Level Transmitter


Float Type Level Transmitter
A circuit, in which the resistance and the reed s/w is serially connected in intervals of 1-2cm, is installed inside the pipe. When the float, equipped with the magnet, moves up and down the pipe by buoyancy, the reed s/w is cut short, and the total resistance value changes until the cutting is summed. The resistance value that had changed based on the level of the fluid is transformed into an electric current signal DC 4-20mA, and put out. This is the most general level control and instruction device. 

- Separately sold Control Unit 
Max. 6m
•304/316SS/PTFE : -10℃∼100℃
•PVC : -10℃∼60℃
•SUS304/316 : Max. 10㎏/㎠
•PVC/PTFE : Max. 2㎏/㎠
•Low cost
•Wide awareness and installation 
•Selection of the detection material 
regarding various substances to be 
•Remote control 
•Explosion proof type possible
(Ex d ⅡB T5 or T4)
4∼20mA DC
24V DC
•Water tanks installed in upper 
stories, Industrial water, Pure 
water, Sewage, Drinking water, Water 
reserves, Cooling water,
•LPG, Chemicals, Fuel tank, Paint,
Various strong acid and alkali fluid 
•Tanks for ships (Optional)
MAT'L : 304/316SS, PVC, PTFE


SGL Gear Type Liquid Level Transmitter


Gear Type Liquid Level Transmitter
액위의 변화에 따라 플로트가 부력에 의해서 상하부로 
이동하면서 기어의 치차값이 변화함과 동시에 가변저항값을 
변화시켜 그 변화된 신호를 전류신호인 DC 4∼20mA로 
변화되어 출력함으로써 레벨을 조절 및 지시할 수 있도록 동작
Max. 10m
ㆍ설치가 간단하며 천정고가 없는 탱크에도 설치가 용이 
ㆍ원격 지시/제어 
ㆍ콘트롤러와 조합하여 사용시 원격지시, 모터/밸브제어 및 경보기능
4∼20mA DC
24V DC


SDT-420 Torque Tube, Displacement Type Level Transmitter


Torque Tube, Displacement Type Level Transmitter
The change of power applied to the displacer according to the change of the fluid level is generated in the form of a twist stress to the Torque Tube, and the twist angle is changed into a straight movement through a complicated mechanism conveyed to the road cell in the form of a pressure change. The errors entailing the temperature change is fixed with a supplementary circuit, and put out in precise DC 4∼20mA of ± 0.2%.
Without the need to go on-site, remote device control is possible through a Two-wire type HART communication signal, and various measurement information and history information is logged through the HART Protocol, enabling the device to be used for the Process Control. It is the first intelligent transmitter in the nation, which was born through the joint research with the Korea Hydraulic Nuclear Power Co., Ltd.
Also, it supports a communication system that realizes the transmitter remote control system(FIMS)'s asset management solution(AMS) selected by Korea Hydro and Nuclear Power, and the communication.
Patent No.: 0361505 
ㆍMax. 450℃
ㆍMax. 200㎏/㎠ (@25℃)
•Korea Hydro and Nuclear Power's joint research development task 
•Max. pressure 100㎏/㎠
•Max. temperature 450℃
•Zero point/automatic adjustment of the measured scope 
•The measurement scope's setting change function 
•Precision of ± 0.2% F.S
•Continuous self-diagnosis function 
•Convenient level detection Scope change
•Remote control by two-wire type SMART + HART communication 
Information transmission and reception, Data Logging, 
Gauge history management 
•FIMS - AMS communication support (Emerson Co.) 
•Essential safety explosion proof(basic)/Pressure-endurable and 
explosion proof(Option) - (Ex ia ⅡC T4)/(Ex d ⅡB T4)

•In power plant facilities, it is generally used partially
with SDG-2000 and in HP,IP,LP Drums(refer to page 13)
•Korea Hydro and Nuclear Power quality grade : S Class
•The Chamber can be manufactured and provided based
on the power technology standard and pressurizer 
manufacturing technology standard(KEPIC) 
ㆍ4∼20mA with HART (Ver. 6.X)
ㆍ15∼30V DC HART
•Power plant HP, IP, LP Drum level control
•Condensed water storage tank, heat exchanger, Heater
•High temperature/pressure type Boiler tank
•chemical distillation tank
•Fuel/ oil tank
Mat'l : 304/316SS