Labmate LMPDM-A100 Portable Density Meter

1. Safety Measures ?

• Read this user manual carefully before operating or servicing the instrument.
• Do not disassemble or replace accessories without proper authorization to avoid compromising safety.
• Do not perform charging operations in explosive or hazardous areas.
• Always follow the specified operating procedures during use.
• Handle the instrument with care; it is a precision device and must not be subjected to impact or rough handling.
• Stop using the instrument immediately if any malfunction or failure is detected.
• Only trained and qualified personnel should operate the instrument, following the manual and all relevant safety standards and regulations.
• If the measuring cell contains water, do not expose the instrument to environments below 0°C to prevent freezing and damage.
• Ensure the power supply is stable and meets the specified rated voltage requirements before use.
• Keep the instrument away from moisture, dust, and direct sunlight to maintain optimal performance.
• Regularly inspect the device for signs of wear, corrosion, or loose connections.
• Store the instrument in a clean, dry, and temperature-controlled environment when not in use.

2. Introduction

The Labmate LMPDM-A100 Portable Density Meter features an ergonomic design, is lightweight, and durable. It utilizes a U-shaped vibrating measurement tube for precise measurements and a digital display for quick and accurate readings. Accurate density and temperature measurement assist in avoiding problems related to both quantity and quality.

3. Features ✨

• Rapid measurement
• Compact and lightweight for easy portability
• Designed to prevent explosions, ensuring safety and reliability
• Less sample requirement
• Measures density and temperature accurately
• Usable as a portable or desktop device
• Capacitive buttons enable touch-sensitive and responsive user control

4. Specifications ?

5. Applications ?

The Portable Density Meter is used to measure the density of liquids and is widely utilized in industries such as chemical, pharmaceutical, environmental monitoring, research laboratories, mining, oil, and gas.

6. Instrument Introduction ?

6.1 Instrument Structure

The instrument consists of the following parts:

• Shell
• Measuring Cell
• Display
• Piston
• Injection Tube

(Refer to Figure-1 for visual representation of the instrument structure)

6.2 Key Description

7. Working Principle ?

The U-shaped vibrating tube method is a highly accurate and widely recognized technique for determining the density of liquids. It involves a U-shaped glass tube, partially filled with the liquid sample, which is oscillated at its natural resonance frequency using piezoelectric elements or other electronic excitation systems. The oscillation frequency directly correlates with the combined mass of the tube and the liquid. Since the mass of the liquid is linked to its density (Mass = Density × Volume), variations in density produce measurable changes in the oscillation frequency: denser liquids yield lower frequencies, while less dense liquids result in higher frequencies.

The system is calibrated using reference standards with known densities to ensure precise measurement of unknown samples. This method offers advantages such as exceptional accuracy, rapid analysis, and minimal sample volume requirements. It is largely unaffected by factors like viscosity or color, making it versatile across various applications. It is prominently employed in industries such as pharmaceuticals, food and beverage, petrochemicals, and environmental monitoring. Its repeatability and sensitivity make it indispensable for quality control and research environments, and it is often integrated into automated digital density meters for streamlined operation.

8. Operations ⚙️

8.1 Display Description

The primary interface displayed upon booting is the measurement interface, showing details like Fuel Oil, API, Density, Temperature, and battery status. (Refer to Figure-2 for a visual representation).

8.2 Preparation

1. Remove the instrument and inspect its appearance along with the pressing piston to ensure it is functioning properly.
2. To turn on the instrument, long-press the power button (⏻). Ensure the temperature display is functioning correctly. Check the U-tube sensor for any foreign debris or dirt and clean if necessary before measurements.
3. Verify that the power level is adequate. If the density meter indicates low power, charge it promptly.
4. To charge the density meter, connect the USB connector of the data cable to the charger, attach the magnetic charging head to the device's charging port, and plug the charger into a 220V (50Hz) power outlet. The power status will be indicated on the display screen, and charging progress will be shown. The typical charging duration is approximately 3 to 4 hours. Disconnect the charger from both the density meter and the power outlet after charging.

Note:

• Charge the device promptly when the battery is low to avoid affecting normal use.
• If the device has not been used for more than one month, it needs to be charged for 4-6 hours.
• When the magnetic charging head connects to the charging port, a charging screen indicator appears. If not, re-plug the magnetic charging head until the indicator appears.

Attention:

• The density meter must be charged in a safe place.
• A special charger for the density meter must be used for charging.

8.3 Measurement Mode

Density measurement involves four steps: Turn on, Aspirating liquid, Measuring, and Draining liquid.

Step 1: Turn on: Long-press the power button (⏻) to turn on the device. Press the adjustment buttons (⏼) to select the measurement method and sample number or name. Direct measurement is possible without selection.

Step 2: Aspirating liquid: Press the piston down as much as possible, insert the sampling tube into the liquid to be measured, slowly lift the piston, and suck the liquid into the measuring cell. (Refer to Figure-5 for visual guidance).

Step 3: Measuring: Wait for the measurement data to stabilize. The screen progress bar turns green in automatic mode, indicating completion. Readings can be viewed vertically or flat. (Refer to Figure-6 for visual examples).

Step 4: Draining liquid: Insert the sampling tube into the waste liquid bottle, press the piston to drain the liquid, and press several times to ensure complete drainage.

Notes for Step 4:

• Ensure the measuring cell is free of bubbles. If bubbles are present, take multiple samples to ensure their removal.
• If unsure about the cleanliness of the measuring cell, take three consecutive samples to ensure the liquid is free from contamination.
• Ensure to fill the measuring cell completely.
• For optimal measurement results, the sample temperature should closely align with room temperature. A deviation exceeding 15°C can hinder accuracy and extend stabilization times.
• If the sample temperature exceeds the range of 0-55°C, the display will show the alarm "T-ERR."
• Always clean the measuring cell after each measurement to ensure no residues are left, guaranteeing accuracy and reliability.
• Use an appropriate solvent (e.g., ethanol, solvent gasoline) to clean the measuring cell.

8.4 Data Storage

Once the data is stable, it can be read directly or stored. Press the storage button (?) to save the data. "Save Complete" will be displayed upon saving. The maximum number of data stored is 5000 groups. (Refer to Figure-7 for visual guidance).

8.5 Operation Completed

After use, clean the measuring cell, then long-press the power button (⏻) to turn off the density meter. Store the device in its box after drying.

Note: Users can use detergent (anhydrous ethanol, gasoline) to clean the measuring cell. During cleaning, continue to inhale and discharge the cleaning agent until the sensor is clean.

8.6 Water Calibration

To ensure accurate measurement, regular calibration is necessary. Deionized water can be used for instrument calibration.

Specific Steps:

1. Follow the process in 9.1.1 Measuring cell module cleaning to clean the measuring cell.
2. After powering on, press the menu button (☰) to enter the menu interface, select [Advanced Settings], and enter the water calibration interface.
3. Inhale deionized water using the instrument to prevent bubbles. Maintain both the deionized water and ambient temperature between 15°C and 25°C.
4. Select Start Calibration and press the confirm button (↩️). The device will start water calibration. The entire process is automatic. (Refer to Figure-8 and Figure-9 for visual guidance on calibration status).

Step 6: Reset Calibration: If users need to remove the calibration value, select reset calibration and press the corresponding button to remove it.

Note:

• If "Calibration failed: Density ER2-1" appears, it indicates bubbles in the measuring cell or that it has not been cleaned.
• If "Calibration failed: Temperature ER1-1" or "Calibration failed: Temperature ER1-2" appears, it means the liquid temperature in the measuring cell exceeds the set range.

9. Maintenance ?️

9.1 Cleaning

Instrument cleaning includes measuring cell module cleaning, piston cleaning, and shell/display cleaning.

9.1.1 Measuring cell module cleaning

To maintain long-term accuracy, clean the measurement cell module with an appropriate solvent before and after each use. Failure to do so may lead to the accumulation of waste liquid and residue, compromising results. Cleaning may also be necessary between individual measurements depending on the application.

Cleaning Steps:

1. Place the injection tube into a suitable container for sample waste liquid.
2. Press the piston to empty the measuring cell.
3. Fill the measuring cell with a suitable solvent.
4. Press the piston multiple times to circulate the solvent within the measuring cell.
5. Press the piston to empty the measuring cell.
6. Let it sit for 10 minutes to dry the measuring cell.

9.1.2 Piston cleaning

When measuring liquids with high viscosity or impurities, some substances may remain trapped inside the piston. To prevent contamination of other liquids, clean the piston.

Cleaning Steps:

1. Pull the piston button outward, pull out part of it, and rotate it 45° counterclockwise to remove the piston. (Refer to Figure-10 for visual guidance).
2. Pull out the upper part of the piston, place it into the cleaning agent, and clean it with a brush. (Refer to Figure-11 for visual guidance).
3. Wipe all parts clean and reassemble.
4. Install and reset the piston. (Refer to Figure-12 for installation guidance).

9.1.3 Housing and display cleaning

Use a soft cloth dampened with a little water or alcohol to clean the case and display.

9.2 Instrument storage

Clean the measuring cell module as described in 9.1.1 Measuring cell module cleaning before storing the instrument for a long period. This prevents waste liquids from collecting in the measuring cell, which could lead to imprecise measurements.