Thermal Conductivity Flow Switch (Sensor) NK300A Type

Brand: Shanghai Zanke Automation Co., Ltd.
Model: NK300A

Product Description

Based on the thermal principle, the enclosed probe contains two resistors. One of them is heated as the detection resistor, and the other is unheated as the reference resistor. When the medium flows, the heat on the heating resistor is taken away, the resistance value changes, and the difference between the two resistors is used as the basis for judging the flow rate.

Product Features

No moving parts, maintenance-free, easy to install, one model is suitable for multiple pipe diameter requirements, the switching value is continuously adjustable, extremely low pressure loss, compact structure, and LED displays the flow trend and switch status.

Product Applications

Gas-liquid dual-purpose, can be used in pneumatic and hydraulic systems, can be used for flow interruption monitoring of circulating water, cutting fluid and lubricating oil, and pump idling protection.

Technical Parameters

• Setting range: Water - 1..150 cm/s; Oil - 3...300 cm/s; Air - 20...2000 cm/s

• Signal output: PNP, NPN, relay, analog (4...20 mA)

• Medium temperature change: ≤4°C/s

• Response time: 1...13 s, typical value 2 s

• Initialization time: Approximately 8 s

• Power supply: 24V±20%DC²) or 230V±15%AC

• Electrical protection: Reverse phase, short circuit, overload protection

• Medium temperature: -20...100°C

• Ambient temperature: -20...80°C

• Storage temperature: -20...90°C

• No-load current: Maximum 80 mA

• Maximum current when powered on: Maximum 400 mA (PNP or NPN type); Maximum 4 A (relay type), 24 VDC or 1 A, 230 VAC

• Flow indication: LED bar (6 pcs)

• Setting method: Potentiometer setting

• Wiring method: M12 connector / optional with 2-meter cable directly

• Pressure resistance range: 100 bar

• Material: Probe: Stainless steel; Shell: PBT

• Weight: 0.4 kg

1. The analog output type is only powered by DC.

2. The analog output type only has an M12 connector, and the AC-powered type only has a direct attached cable.

Wiring Diagram

• PNP: 1 (brown) - L+; 2 (white) - ; 3 (blue) - ; 4 (black) - PNP output

• RELAY (relay output): 1 (brown) - ; 4 (black) - NC; 5 (gray) - NO; 2 (white) - L+ (L); 3 (blue) - COM L- (L)

• NPN: 1 (brown) - ; 2 (white) - ; 3 (blue) - ; 4 (black) - NPN output

• 4...20 mA: 1 (brown) - L+; 3 (blue) - ; 4 (black) - 4...20 mA output

Installation Instructions

Insertion type flow sensor

Installation needs to be used with a welded sleeve or a tee.

Special attention:

• The straight distance from the elbow or intersection should not be less than 4 times the pipe diameter, i.e., a ≥ 4d.

• When the medium cannot be completely filled, the sensor should be installed at the bottom of the pipe.

• If there may be sediment in the pipe, install the sensor horizontally on the side and ensure there are no air pockets near the probe.

• Dual-probe types need to be installed according to the position shown in (D).

• When the monitored medium has the characteristic of low thermal conductivity (such as some oils and liquids with high fat content) and the temperature changes rapidly during monitoring, the position of the sensor and the direction of the fluid must be considered. For the insertion type compact sensor, the cable direction or probe A4 and symbol must be perpendicular to the fluid direction.

Introduction to Wholesale Manufacturer of Thermal Conductivity Flow Switch (Sensor) NK300A Type

Shanghai Zanke is a wholesale manufacturer of high-sensitivity special thermal conductivity flow switches. At this stage, the main products of Shanghai Zanke Co., Ltd. include flow switches, pressure switches, temperature switches, electromagnetic flowmeters, vortex flowmeters, turbine flowmeters, ultrasonic flowmeters, level (liquid) flowmeters and other instruments. Application industries: petroleum chemical industry, natural gas, machinery, electric power, metallurgy, building materials, food and pharmaceutical manufacturing, agriculture, environmental protection, etc. (Our company can customize instrument specifications according to users' special requirements and on-site working conditions, and provide installation and commissioning services.)