LRP Series Three-Rotor Flow Meter

Overview   
The LBJ series metal vane flowmeter (referred to as the flowmeter) is a positive-displacement flow instrument. It is designed for the continuous or intermittent, highly precise measurement of liquid flow rates in pipelines. Featuring high measurement accuracy, smooth operation, low noise, zero pulsation, large flow capacity, resistance to sludge and sand buildup, extended service life, strong viscosity adaptability, and ease of maintenance, this flowmeter is widely used across industries such as petroleum, chemical processing, light industry, transportation, and commerce. It is particularly well-suited for metering industrial media like crude oil, residual oil, refined petroleum products, and light hydrocarbons. 
This flowmeter features on-site indication with direct digital readout, as well as the ability to output electrical pulse signals for use with display instruments and computer systems—enabling centralized, long-distance control and management of pipeline flow.

Structure and Working Principle of Flow Meters   
1. The Structure of the Flow-Driven Calculation Pavilion   
The flowmeter consists of several key components: the main body (flow transmitter), connecting parts, and the meter head (indicator). The main body primarily includes a rotor, cams, camshaft scraper plates, connecting rods, rollers, as well as cover plates and the housing. Inside the housing, there’s a circular, hollow cylinder. The rotor itself is a rotating, hollow, thin-walled cylinder. When using two pairs of scraper plates, four slots are radially cut into the rotor’s cylindrical wall at 90° angles to each other. For three pairs of scraper plates, six slots are instead cut at 60° angles. These scraper plates slide freely within their respective slots, allowing them to extend and retract smoothly. Each set of four scraper plates is connected by two cross-linked rods positioned at right angles to one another, while three pairs of scraper plates are linked via three rods arranged at 60° angles in space—ensuring they never collide. A bearing is placed between the scraper plates and the cams, and all four or six bearings roll along a stationary, specially shaped cam. This mechanism enables the scraper plates to alternately extend outward from the rotor and then retract back inside, maintaining precise operation. Additionally, the flowmeter’s main body (the flow transmitter) features a dual-shell design. This innovative approach not only eliminates measurement inaccuracies caused by external forces such as pressure differences and pipeline tension-induced deformation of the flowmeter chamber but also enhances ease of maintenance and installation. 
Maintenance and servicing: The flowmeter's indicator features two sets of cumulative counting mechanisms. The small-digit counter displays the total accumulated count of the flowmeter, while the large-digit counter shows the cumulative reading at any given moment—and can also be reset to zero. 
2. The working principle of flow meters

When the measured liquid flows through the flowmeter, it sets the scraper and rotor in motion, causing them to rotate. At the same time, the scraper extends or retracts radially along a unique, specially designed path. Notably, the distance between the end faces of every pair of opposing scrapers remains constant. As the scrapers continuously rotate, this creates a fixed metering space (metering chamber) within the cavities of the adjacent rotor housing sections—as well as between the upper and lower cover plates. With each full rotation of the rotor, exactly four (or six) identical, closed volumes of liquid are discharged—precisely corresponding to the calibrated chamber volume. The rotor’s rotational movement is then transmitted via a sealed coupling and transmission system to the counting mechanism, directly indicating the total volume of liquid that has passed through the flowmeter. 
The flowmeter equipped with a pulse transmitter can output electrical pulse signals, which can be processed by computers or electronic display instruments to indicate both the cumulative and instantaneous flow rates of the liquid passing through the meter—enabling seamless control of various automated systems.

3. Combined Configurations of Flow Meters   
The flowmeter employs a modular, building-block assembly design. It consists of a main unit (the flow transmitter), a precision adjuster, a pulse transmitter, a heat sink, and a counter. With the exception of the transmitter, all other components are standard, off-the-shelf parts, allowing users to freely combine and select among the four configurations shown in Figure 2, based on their specific needs.

Main Technical Specifications 
Accuracy class: ±0.2% (range ratio 10:1); repeatability better than +0.03%. 
±0.1% (range ratio 5:1), with repeatability better than +0.03%; 
±0.5% (range ratio of 10:1), with repeatability better than +0.05%.

Explosion-proof rating: Ex db ⅡBT4 
Protection rating: IP67 
Display format: Large-digit counter—5-digit large digits with zero-reset capability, and 8-digit small digits without zero-reset.

Smart Flow Totalizer: 4-digit instantaneous flow rate: 000.0 to 999.9 m³/h, 8-digit totalized flow: 0000.0000 to 9999.9999 m³/h, Output signals: pulse signal, dual-channel pulse signal, pulse signal with 4–20 mA (3-wire configuration), 1–5 V, and 4–20 mA plus HART protocol (3-wire configuration). MODBUS.RS485 communication protocol available. (Remote transmission distance up to ≤300 m.)

Power supply: DC 12V–24V

Technical Specifications Table

Note: Medium viscosity ranges from 0.3 mPa·s to 3000 mPa·s 
Note: When the fluid viscosity exceeds 100 mPa·s, the maximum flow rate must be multiplied by the following factor:

2. Pipe Connection Flange

3. Execution Standard 
This enterprise standard: JB/T9242-2015 "Positive Displacement Flow Meters" and Q/ZAY 15-20233 "LBJ Series Metal Vane Flow Meters." 
Characteristic curve (see Figure 3) 
① Gasoline 0.7 mPa·s 
② Water 1 mPa·s 
③ Light diesel oil, 3.5 mPa·s 
④ Heavy oil 100 mPa·s

5. Flow Meter External Dimensions