An introduction to water flow switches that are common in chillers in HVAC engineering systems
Water flow switches play an important role in chillers, and they are often used to monitor and control cooling water flow. A chiller is a refrigeration device used in places such as industrial, commercial, and large buildings, and its main function is to transfer heat from one place to another to maintain the temperature of a particular area within the desired range. In the actual application process, there are mainly differential pressure water flow switches, target water flow switches, ** water flow switches, etc., among which the application of differential pressure and target water flow switches is more extensive.
1. Target-flow water flow switch.
A target-flow switch is a device used to monitor fluid flow, commonly used in water flow control and flow monitoring applications. It is also known as a flow rate switch or flow rate monitor. This type of water flow switch detects the speed at which the fluid flows through it to determine if the flow rate is within a set range in order to trigger the corresponding control action or alarm.
The structure of a target-type flow switch typically includes the following main components:
Pipe connector: This is the part where the switch connects to the piping system. It typically includes inlet and outlet connections that enable fluid to pass through the switch.
Target or baffle: This is the moving part in the switch and the heart of it. It is usually a plate-like or leaf-like structure that can move under the action of fluids. When the fluid velocity changes, the target moves under the influence of the fluid pressure.
Sensor: The sensor is used to detect the position or movement of the target to determine if the flow rate is within a preset range. Sensors can be mechanical, electronic, or other types of sensors. Mechanical sensors may use physical contact or mechanical connections to measure the position of the target. Electronic sensors may use resistance, Hall effect, or other techniques to measure the position of a target.
Control system: The control system is connected with the sensor, and the corresponding control operation is triggered according to the signal of the sensor. For example, if the flow rate exceeds the set range, the control system can close the valve, give an alarm signal, or perform other actions.
Adjustment device (optional): Some target-flow water flow switches may have a regulation device that allows the user to adjust the sensitivity of the switch or trigger threshold as needed. This allows the flow rate control to be optimized according to the actual application.
Enclosure and sealing: Switches are usually protected by enclosures to prevent damage from the external environment. Seals are used to prevent fluid from leaking or entering the inside of the switch.
The working principle of the target flow switch is as follows:
Structure: A target-flow switch usually consists of a pipe connector, a movable target (or baffle) and a sensor. Sensors can be mechanical, electronic, or other types and are used to detect the position or flow rate of the target.
Fluid flow: When the fluid passes through the pipe, it puts the target under pressure from the fluid, causing it to move. The amount of movement of the target is directly proportional to the velocity of the fluid. When the flow rate is within the preset range, the position of the target is maintained in a specific area.
Trigger Action: If the flow rate is outside the set range, the target moves to a specific position, which triggers the sensor and activates control actions such as closing the valve, sending an alarm signal, etc. This can help prevent problems caused by flow rates that are too high or too low, such as equipment damage or interruptions.
2. Differential pressure water flow switch.
A differential pressure flow switch is a device used to monitor differences in fluid pressure and is typically used to control and protect liquid flow systems. Suitable for different fluid media and applications, these switches can help ensure that the system operates within a safe range.
The structure of a differential water flow switch usually includes the following main components:
Connector: The connector is the part that connects the differential pressure flow switch to the piping system. It includes inlet and outlet connections that enable fluid to pass through the switch.
Pressure Sensor: A pressure sensor is a key component in measuring the pressure of a fluid at different locations. There are usually two or more sensors, each mounted in a different location. The sensor transmits the measured pressure signal to the control unit.
Control unit: The control unit is the part that processes the sensor signal and makes corresponding judgments. Based on the measured pressure differences, the control unit determines whether the system is operating within the normal range and then triggers the corresponding control actions, such as closing the valve or issuing an alarm signal.
Adjustment device (optional): Some differential pressure flow switches may have a control device that allows the user to adjust the sensitivity of the switch or the trigger threshold as needed. This helps to adapt to the needs of different applications.
Enclosure and sealing: Switches are usually protected by enclosures to prevent damage from the external environment. Seals are used to prevent fluid from leaking or entering the inside of the switch.
Display and control panel (optional): Some differential pressure flow switches may have a display panel that shows the current pressure difference or system status. It can also have control buttons that enable the user to manually control the switch operation.
The working principle of the differential water flow switch is as follows:
Construction: Differential pressure flow switches typically consist of a device or pipe connection, two or more pressure sensors, and a control unit. These pressure sensors are mounted in different positions and sense the pressure as the fluid passes through.
Differential pressure measurement: As the fluid passes through a device or pipe, the fluid generates different pressures at different locations. The pressure sensor measures the difference in pressure at these locations. If the fluid flow rate changes or the system becomes clogged, the differential pressure will also change.
Control operation: According to the change of pressure difference, the control unit will judge whether the system is operating within the normal range. If the pressure difference exceeds a preset threshold, the control unit may trigger actions such as closing the valve, giving an alarm signal or stopping the flow.
3. ** type water flow switch.
A *-type water flow switch is a heat-sensitive element-based device that monitors liquid flow and temperature and triggers control actions under specific conditions. These switches are commonly used in liquid flow systems to detect anomalies such as low or high flow rates during fluid flow.
The working principle of the *type water flow switch is as follows:
Construction: A water flow switch usually consists of a thermistor or cable, a temperature sensor, a control unit, and a connection circuit. **Typically located in a fluid channel, flow rate and temperature can be measured by the heat conduction of the fluid.
Heating: When the fluid flows through the device, it is heated. If the flow rate is normal, the fluid will take away the heat on the **, so that the temperature of the ** will be kept at a relatively stable level.
Temperature Measurement: The temperature sensor measures the temperature of **. If the flow rate decreases or is interrupted, the cooling effect of the fluid on ** will be weakened, and the temperature of ** will increase.
Control operation: The control unit will judge whether the flow rate is within the preset range according to the temperature change. If the temperature rises above the threshold, the control unit may trigger actions such as closing the valve, giving an alarm signal, or stopping the flow.
*The structure of the water flow switch usually includes the following main components:
*(Thermal element) :* is the core part of ** type water flow switch. It is usually a thermistor or thermal cable, which is placed in a fluid path. As the fluid flows through it, it is heated or cooled, causing its temperature to change.
Temperature Sensor: A temperature sensor is used to measure the temperature change of **. The sensor transmits the measured temperature signal to the control unit.
Control unit: The control unit is the part that processes the sensor signal and makes corresponding judgments. According to the temperature change of **, the control unit will judge whether the flow rate is within the preset range, and then trigger the corresponding control actions, such as closing the valve, sending out an alarm signal, etc.
Connection circuits: Connection circuits are used to connect **, temperature sensors, and control units together for signal transmission and data processing.
Display and control panel (optional): Some water flow switches may have a display panel that shows the current temperature change or system status. It can also have control buttons that enable the user to manually control the switch operation.
Enclosure and sealing: Switches are usually protected by enclosures to prevent damage from the external environment. Seals are used to prevent fluid from leaking or entering the inside of the switch.