I. Overview

The LFX rotary steam flow meter is an instrument designed to measure the cumulative mass flow of steam, featuring a mechanical structural design. It provides on-site display through an indicator dial (mechanical) or LCD screen, allowing the reading of the mass of steam that has passed through the meter. It can also output pulse signals and includes manual pressure compensation or automatic temperature compensation functions. Due to its simple structure, moderate price, and wide measurement range, it is suitable for applications requiring steam flow measurement in sectors such as petroleum, chemical, textile, heating, and the washing industry.

II. Working Principle

    When the measured steam flows through the flow meter body, it is throttled by an orifice plate. Under the action of the pressure difference before and after, a portion of the steam passes through the nozzle into the shunt pipe, forming a jet that drives the impeller at the upper end of the rotor shaft to rotate. The lower end of the rotor shaft is equipped with two damping blades that rotate in a damping chamber filled with damping fluid, enabling the impeller to absorb the kinetic energy of the jet. When the rotational torque of the impeller balances with the damping torque, the rotational speed of the impeller is proportional to the mass flow of the measured steam passing through the flow meter. After calibration and scaling, the actual cumulative steam flow is reflected on the indicator dial. The steam flow meter mainly consists of three major components: the throttling body, the damper, and the indicator. It operates on the differential pressure-shunt principle. When the measured steam medium enters the throttling body of the flow meter, one portion passes through the main pipeline's throttling orifice plate, while another portion flows through the shunt pipe to the nozzle, forming a jet that acts on the impeller, generating torque. This causes the impeller to drive the rotor shaft to rotate. Damping blades are installed at the lower part of the rotor shaft in a damping chamber filled with damping fluid, restricting the impeller's rotation. As a result, its rotational speed is much slower than the steam jet speed, allowing the impeller to absorb the kinetic energy of the steam jet. The rotational speed corresponds to the torque generated by the steam and the damping torque, establishing a quantitative relationship where the impeller speed is proportional to the flow rate.

III. Main Parameters and Performance Indicators

1. Measured Medium    Saturated steam, slightly superheated steam

(Degree of superheat ≤20℃)

2. Nominal Diameter        02   05   08   10;

3. Operating Temperature    183℃(02)  

240℃(05;  08;  10);

4. Ambient Temperature        Required 0℃～55℃

(Other temperatures available upon order)

5. Operating Pressure Range   0.03-1.0  

0.05-1.6 (05;  08;  10);

6. Installation Method         Horizontal installation

7. Density Compensation Method     Mechanical type with manual pressure compensation;

Steam Flow Meter Installation Precautions

　　 I. Requirements for Straight Pipe Sections:

　　 1. The flow meter should be installed horizontally on the pipeline (with pipeline inclination within 50 degrees). During installation, the axis of the flow meter should align with the pipeline axis, and the flow direction must be consistent.

　　 2. The upstream pipeline should have a straight section of no less than 10D in equal diameter. If the installation site permits, it is recommended to have an upstream straight section of 20D and a downstream section of 5D.

　　 II. Requirements for Piping:

　　 The inner diameter of the upstream and downstream piping at the installation point should match the inner diameter of the flow meter.

　　 III. Requirements for Bypass Pipes:

　　 To ensure that maintenance of the flow meter does not affect normal medium use, shut-off valves (globe valves) should be installed on the pipeline both before and after the flow meter, along with a bypass pipeline. The flow control valve should be installed downstream of the flow meter. During operation, the upstream shut-off valve should be fully open to prevent unstable flow conditions in the upstream section.

　　 IV. Requirements for External Environment:

　　 The flow meter should be installed indoors. If installed outdoors, measures for sun protection, rain protection, and lightning protection should be taken to avoid affecting its service life.

　　 V. Installation Location:

　　 The flow meter should be installed in a location that is easy to maintain and free from strong electromagnetic interference.

　　 VI. Requirements for Installation Welding:

　　 1. The user should provide a pair of standard flanges welded to the upstream and downstream pipelines. Welding with the flow meter in place is not allowed!

　　 2. Before installing the flow meter, clear the pipeline of debris such as fragments, welding slag, stones, and dust. Install a 5-micron mesh filter upstream to block droplets and sand particles. Use a pipe of equal diameter (or a bypass pipe) instead of the flow meter to blow through the pipeline to ensure the flow meter is not damaged during use.

　　 3. During installation, ensure that the sealing gasket between the flanges does not protrude into the pipeline to avoid interfering with normal flow measurement.

　　 VII. Grounding Requirements for the Flow Meter:

The flow meter should be grounded and must not share a ground with strong electrical systems.

For details, please consult a sales engineer.