Product Overview

The Mechanical Paddle Flow Switch NK01B is designed for reliable liquid flow monitoring in industrial pipelines up to DN125 (5″). The switch uses a spring-supported paddle mechanism that activates an internal SPDT micro switch when the flow reaches the preset switching point.

The modular paddle design allows flexible adjustment for different pipe sizes and flow ranges. With complete isolation between the mechanical sensing components and electrical contacts, the NK01B offers stable operation, good repeatability, low pressure loss, and strong resistance to contamination.

The factory-standard configuration includes five interchangeable paddles, allowing convenient adaptation to various pipeline diameters and operating conditions.

---

Working Principle

The NK01B operates using a mechanical paddle sensing principle.

As liquid flows through the pipeline, it pushes against the spring-supported paddle. When the flow force reaches the preset value, the paddle moves and actuates the internal SPDT micro switch, generating an electrical switching signal for flow monitoring, alarm, or equipment protection.

When the flow decreases below the switching threshold, the paddle returns to its original position under spring force and the switch resets automatically.

---

Product Features

• Mechanical paddle flow detection
• Adjustable switching point
• Spring-supported paddle design
• SPDT output (Normally Open + Normally Closed)
• Low pressure loss
• Good repeatability
• Wide adjustable flow range
• Five interchangeable paddles included
• Suitable for multiple pipeline sizes
• Strong anti-contamination capability
• Complete isolation between mechanical and electrical components
• Easy installation and on-site adjustment

---

Applications

Suitable Industries

• Water treatment
• Cooling water systems
• Industrial circulation systems
• Pump protection
• HVAC systems
• Machinery manufacturing
• General industrial process control

Typical Applications

• Flow monitoring
• Pump protection
• Cooling water detection
• Equipment interlock
• Process automation
• Liquid circulation systems

---

Technical Specifications

---

Materials

---

Adjustable Flow Range

The NK01B supports multiple paddle configurations for different pipe diameters and adjustable flow ranges.

Available Pipe Sizes

• 1″
• 1¼”
• 1½”
• 2″
• 2½”
• 3″
• 4″
• 5″
• 6″

The factory supplies five paddle sizes, which can be selected or combined according to pipeline diameter and required switching flow.

(Refer to the selection table for detailed adjustable flow ranges and hysteresis values.)

---

Selection Guide

Model Example

NK01B-025-M-L

Special customization is supported according to application requirements.

---

Installation Requirements

• Install in the direction of the medium flow.
• Ensure the paddle is correctly positioned inside the pipeline.
• Select the appropriate paddle according to the pipe diameter.
• Verify the required switching flow before installation.
• Adjust the switching point if necessary during commissioning.

---

Ordering Information

To ensure proper factory configuration, please provide the following information when placing an order:

For Liquid Applications

• Flow direction
• Medium type
• Pipe diameter
• Expected switching value

For viscous liquids, also specify:

• Medium viscosity
• Operating temperature
• Medium type

For Gas Applications

Please specify:

• Medium type
• Operating pressure (gauge or absolute pressure)
• Operating temperature

The switching point can be preset before shipment according to the supplied operating conditions.

Imported micro switches are available as an option upon customer request.

---

Why Choose the NK01B?

The NK01B provides a simple and reliable mechanical solution for liquid flow detection without requiring external calibration equipment or complex electronics.

Adjustable Paddle Design

Five interchangeable paddles allow one switch to accommodate multiple pipeline sizes and flow conditions.

Reliable Mechanical Operation

The spring-supported paddle mechanism provides repeatable switching performance while maintaining complete isolation between mechanical components and electrical contacts.

Low Pressure Loss

The paddle structure minimizes pressure loss during normal operation while maintaining effective flow detection.

Flexible Installation

The adjustable flow setting enables the switch to be adapted to different process requirements.

Easy Maintenance

The simple mechanical design allows convenient inspection and replacement when required.

---

Application Case

Cooling Water Pump Protection in Industrial Circulating Systems

In industrial cooling water systems, maintaining continuous liquid circulation is essential for protecting pumps and heat exchangers. The NK01B mechanical paddle flow switch can be installed in the pipeline to monitor whether flow reaches the required operating level.

When the liquid flow exceeds the preset switching value, the spring-supported paddle actuates the internal SPDT micro switch, sending a switching signal to the control system. If flow decreases below the preset value, the switch resets automatically, allowing alarms or equipment interlocks to help protect the system.

Its interchangeable paddle design enables the same switch to be adapted to multiple pipe sizes while maintaining stable operation and low pressure loss.

---

Frequently Asked Questions (FAQ)

1. What measuring principle does the NK01B use?

It uses a mechanical spring-supported paddle to detect liquid flow.

---

2. What output does the switch provide?

SPDT output including:

• Normally Open (NO)
• Normally Closed (NC)

---

3. What is the maximum working pressure?

The maximum working pressure is 16 bar.

---

4. What is the maximum medium temperature?

Up to 90°C.

---

5. What protection rating is available?

Standard protection rating is IP33, with IP67 protective housing available as an option according to the selection table.

---

6. How many paddles are supplied?

The standard package includes five interchangeable paddles.

---

7. Can the switching point be preset before delivery?

Yes. The factory can preset the switching value when operating conditions are provided.

---

8. What information is required when ordering?

Please provide:

• Medium type
• Flow direction
• Pipe diameter
• Expected switching value

For viscous liquids or gases, additional operating information should also be supplied.

---

Optional Services

• Factory preset switching point
• Multiple paddle configurations
• IP67 protective housing option
• Imported micro switch option
• Product customization according to operating conditions
• Installation and technical support

---

Industries Served

The NK01B Mechanical Paddle Flow Switch is suitable for:

• Water Treatment
• Industrial Water Systems
• HVAC
• Machinery Manufacturing
• Chemical Processing
• Power Generation
• General Industrial Automation