Description
Plastic Threaded Rotameter for Water – 10 to 100 LPH
The Plastic Threaded Rotameter for Water, Range 10 to 100 LPH is a compact, economical, and reliable variable-area flow meter designed for accurate visual measurement of water flow in industrial, commercial, laboratory, and utility applications. This rotameter combines a polycarbonate flow body, ABS threaded end connections, and SS 316L float to provide a practical solution for applications where dependable flow indication, easy installation, and cost-effective operation are required.
With a flow measurement range of 10 to 100 Litres Per Hour (LPH), this model is particularly suitable for relatively low-flow water applications. Its 1/2-inch BSP (M) threaded connections at the top and bottom allow convenient inline installation, with the inlet at the bottom and outlet at the top. This vertical installation arrangement follows the operating principle of a conventional rotameter, where the float rises or falls according to the flow rate passing through the tapered flow passage.
The rotameter is designed specifically for water with a specific gravity of 1. It can operate at a maximum temperature of 60°C and a maximum operating pressure of 5 kg/cm², making it suitable for a broad range of general-purpose water-flow monitoring applications.
A rotameter, also known as a variable-area flow meter, provides flow indication based on the position of a float inside a specially designed flow tube. As water enters from the bottom, it causes the float to rise. The float stabilizes at a position where the upward force generated by the flowing fluid balances the downward force acting on the float. The operator can then read the corresponding flow rate directly from the graduated scale.
This design provides a simple method of monitoring flow without requiring electrical power, making the Plastic Threaded Rotameter an attractive option for applications where straightforward and continuous visual flow indication is required.
10 to 100 LPH Flow Measurement
The specified flow range of 10 to 100 LPH makes this rotameter suitable for low-flow water measurement.
The scale provides a direct visual indication of the approximate water flow rate, allowing operators to quickly identify whether the flow is within the required operating range.
This can be useful for:
- Water circulation systems
- Cooling-water lines
- Water treatment equipment
- Filtration systems
- Dosing and utility systems
- Laboratory water circuits
- Small process equipment
- Industrial machinery
- RO and water purification systems
- General water-flow monitoring
The instrument has an accuracy specification of 2% of full scale, providing dependable flow indication for general industrial and utility applications.
Variable-Area Flow Measurement Principle
The Plastic Threaded Rotameter operates on the variable-area principle.
Water enters the instrument through the bottom connection and flows upward through the measuring section. As the flow increases, the float moves upward. When the flow decreases, the float moves downward.
The float position corresponds to the flow rate indicated on the scale.
The design provides several advantages:
- Simple mechanical operating principle
- No external electrical power required for indication
- Easy-to-read visual measurement
- Continuous flow indication
- Simple installation
- Low maintenance requirements
- Economical operation
Because the instrument uses a mechanical float and graduated scale, it can provide immediate visual feedback to operators.
Polycarbonate Body Construction
The flow body is manufactured from polycarbonate, providing a lightweight and transparent construction.
The transparent body allows the operator to observe the float directly during operation. This is particularly useful when checking flow stability, identifying unexpected flow changes, or confirming whether the system is operating.
Polycarbonate is also suitable for many general industrial and water applications because of its combination of transparency, strength, and lightweight characteristics.
The transparent construction makes the instrument easy to inspect without dismantling the flow line.
SS 316L Float
The rotameter is equipped with an SS 316L float.
Stainless steel 316L is widely used in instrumentation because of its corrosion-resistant characteristics and suitability for various industrial environments.
The float is the primary moving element of the rotameter and responds directly to changes in water flow. Its position inside the flow tube provides the visual indication used to determine the flow rate.
The use of an SS 316L float provides a durable and robust measuring element for suitable water-flow applications.
ABS Threaded End Connections
The instrument features ABS end connections with 1/2-inch BSP (M) threaded connections.
Both top and bottom connections are provided for inline installation. The standard flow direction is:
Inlet: Bottom → Outlet: Top
Correct vertical installation is important because the float relies on gravity and upward fluid movement to provide the intended measurement.
The threaded connection arrangement allows the rotameter to be integrated into compatible piping systems using appropriate fittings and sealing methods.
Operating Temperature and Pressure
The Plastic Threaded Rotameter is specified for:
Maximum Operating Temperature: 60°C
Maximum Operating Pressure: 5 kg/cm²
These limits should be observed during installation and operation.
The rotameter is intended for suitable water applications within these specified operating conditions. Application conditions should always be reviewed before installation, particularly where pressure surges, elevated temperatures, chemical exposure, or unusual fluid characteristics may be present.
Tamper-Proof Scale Sticker
The instrument is supplied with a tamper-proof scale sticker.
The graduated scale allows operators to identify the flow rate corresponding to the float position. The tamper-proof construction helps maintain the integrity of the scale marking and reduces the possibility of accidental alteration during normal use.
The scale is specified for flow indication in LPH/LPM, as applicable to the supplied configuration.
Compact and Space-Saving Design
The rotameter has approximate dimensions of:
165 mm Height × 45 mm Width
Its compact design makes it suitable for installations where available space is limited.
The lightweight plastic construction also makes the instrument convenient for applications where a compact flow indicator is preferred over larger metallic flow-meter assemblies.
Easy Installation and Operation
The instrument is designed for straightforward installation into a compatible vertical pipeline.
For proper operation:
- Install the rotameter vertically.
- Ensure the flow direction is from bottom to top.
- Connect the 1/2-inch BSP (M) connections using compatible fittings.
- Ensure the operating pressure remains within the specified limit.
- Ensure the water temperature does not exceed 60°C.
- Allow the flow to stabilize before taking a reading.
- Read the flow value corresponding to the float position.
Correct installation helps ensure reliable and repeatable indication.
Applications
The Plastic Threaded Rotameter can be used in numerous applications where visual water-flow monitoring is required.
1. Water Treatment
Suitable for monitoring water flow through treatment, filtration, and purification equipment.
2. Cooling Systems
Can be used for monitoring water circulation through suitable cooling equipment and machinery.
3. Laboratory Equipment
The compact construction and low-flow range make it suitable for compatible laboratory water circuits and testing systems.
4. RO and Purification Systems
Can provide visual flow indication in appropriate reverse-osmosis and water purification equipment.
5. Industrial Machinery
Suitable for monitoring cooling or utility-water flow in compatible machines.
6. Process Equipment
Can be installed on suitable low-flow water lines to provide local flow indication.
7. Utility Systems
Useful for general-purpose monitoring of water flow where a simple mechanical indication is preferred.
Key Features
- Plastic threaded rotameter for water
- Flow range 10 to 100 LPH
- Suitable for water, SG 1
- 2% of full-scale accuracy
- Polycarbonate body
- SS 316L float
- ABS end connections
- 1/2-inch BSP (M) top and bottom connections
- Inline installation
- Bottom inlet and top outlet
- Maximum operating temperature 60°C
- Maximum operating pressure 5 kg/cm²
- Tamper-proof scale sticker
- LPH/LPM scale graduation
- Compact dimensions of approximately 165 × 45 mm
- Easy visual flow indication
- No external power required for mechanical indication
- Economical and low-maintenance design
Why Choose This Plastic Threaded Rotameter?
The Plastic Threaded Rotameter provides a practical combination of simple operation, compact construction, visible flow measurement, and economical design. Its 10–100 LPH range makes it particularly suitable for low-flow water applications, while the transparent polycarbonate body allows the float position to be observed directly.
The SS 316L float provides a robust measuring element, while the ABS threaded connections provide a lightweight and convenient connection arrangement. With a maximum operating temperature of 60°C and maximum operating pressure of 5 kg/cm², it can be used for many general-purpose water-flow monitoring applications within its specified operating limits.
For users looking for a straightforward and cost-effective method of checking water flow without requiring an electronic display or external power supply, this rotameter offers an efficient solution.
Japsin Instrumentation – Since 1974

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