Brand:Shanghai Youyi Instrument Co., Ltd
Name: Rotational Viscometer
model:NDJ-4

Product Usage:

The Shanghai Right One Instrument NDJ-4 rotary viscometer is suitable for measuring the viscosity and rheological properties of various liquids and semi fluids. Widely used in determining the viscosity of various fluids such as oils, paints, food, drugs, cosmetics, adhesives, etc. It is one of the precision instruments commonly used in new product development, product quality control testing and analysis.

Technical parameters:

working principle:

1. The lifting system adopts a helical rack/helical gear method:

The rotational viscometers of other domestic manufacturers use a straight rack/straight gear method, where the rack and gear only have one tooth in contact during operation, and can be easily adjusted upwards; It will inevitably slide downwards, and if it is avoided, it will be difficult to adjust upwards. Our factory's rotational viscometer uses a helical gear method, where the helical gear has three teeth in contact with the helical gear during operation, effectively overcoming the disadvantages of the straight gear/helical gear method. It is easy and convenient to move up and down without slipping. The method of helical gear/helical rack is much more difficult in terms of processing cost than the method of straight gear/helical rack

2. A universal joint has been added at the interface connecting the rotor:

Usually, the rotor of a rotational viscometer is directly rigidly connected to the rotating shaft. Non concentricity of the shaft or rotor can cause the rotor to shake during testing, affecting the accuracy of the test. The rotating shaft tip is thin and sharp, and even accidental collisions can often cause the shaft tip to bend or even be damaged. The use of universal joints can effectively reduce testing errors caused by the misalignment of the shaft and rotor, and protect the shaft tip from damage caused by impact. This structure has not been seen by other domestic manufacturers, only high-end imported viscometers (universal joints require imported CNC machine tools for processing, with very high precision requirements, so the cost has also increased significantly).

3. The variable speed gear is made of high wear-resistant and high-performance engineering plastic compression:

In order to ensure smooth operation and accurate measurement of the rotational viscometer, high precision is required for gear machining. At present, the gears used in the production of viscometers by other domestic manufacturers are processed from metal sheets and riveted with other parts. Due to the limitations of this processing method, it is difficult to meet the design requirements, resulting in unstable operation of the viscometer during operation, such as shaking, shaking, pointer jumping, and loud noise. Our factory uses high-performance engineering plastics (which have better performance than metals) to press and shape the entire component of the gear in one go. Due to the high precision of the mold, the processed gear fully meets the design requirements, fundamentally solving the problems caused by metal gears. This makes the viscosity meter work very smoothly and improves the testing accuracy.

4. Fine processing and excellent performance:

Each component is carefully processed and debugged, with strict quality control to ensure that users can purchase and use it with peace of mind.

Operation usage:

1.Prepare the tested liquid and place it in a diameter not less than70mmAccurately control the temperature of the measured liquid in a beaker or straight cylindrical container.

2.Install the protective frame onto the instrument (screw it in to the right and remove it to the left).

3.Screw the selected rotor into the connecting screw (insert to the left and remove to the right). Rotate the lifting knob to slowly lower the instrument, and gradually immerse the rotor into the measured liquid until the rotor liquid level mark is parallel to the liquid level. Adjust the instrument level, turn on the motor switch, rotate the speed knob to increase the desired speed, align with the speed indicator point, and rotate the rotor in the liquid. After multiple rotations, it is generally（20-30）sOr, according to the specified time, wait for the pointer to stabilize before reading. Press the pointer control lever to fix the reading, and turn off the motor when the pointer reaches the reading window (note:1.Do not exert too much force.2.When the speed is slow, the control lever can be used to read directly. At this time, the pointer stops within the reading window to obtain measurement data. When the motor is turned off and the pointer is not within the reading window, you can continue to hold down the pointer control lever and repeatedly turn on and off the motor. After several practice sessions, you can master it proficiently and make the pointer stop within the reading window to read data.

4.When the value pointed by the pointer is too high or too low, the rotor and speed can be changed, and the reading must be on the scale30-90It's better between them.

5.Selection of range, coefficient, rotor, and speed:

a.First, roughly estimate the viscosity range of the liquid being tested, and then select the appropriate rotor and speed based on the range table.

As measured, approximately3000mPa.sThe following combinations can be used for left and right liquids:

2Number rotor6turn/branch or 3Number rotor30turn/branch

b.When the approximate viscosity of the tested liquid cannot be estimated, it should be set to a higher viscosity first, and a rotor with a small volume to a large volume and a speed from slow to fast should be used. The principle is to use a small volume rotor and slow speed for high viscosity liquids, and a large volume rotor and fast speed for low viscosity liquids.

c.Coefficient: The reading indicated by the pointer on the dial during measurement must be multiplied by the specific coefficient on the coefficient table to obtain the measured dynamic viscosity（mPa.s）.

Namely, η=k×α In the formula η - dynamic viscosityK——Coefficient α - viscosity indicated by the pointer (deflection angle)

d.Correction of frequency error: When the power frequency is not correct, it can be corrected according to the following formula.

Actual viscosity=Indicating viscosity x (nominal frequency)/Actual frequency)

e.Conversion of commonly used viscosity units:

Conversion of Common Dynamic Viscosity Units:

1Li Po（1cP）=1Millipascals per second（1mPa.s）

100Li Po（100cP）=1Bo Bo（1P）

1000Millipascals per second（1mPa.s）=1Pascal's Second（1Pa.s）

Conversion between dynamic viscosity and kinematic viscosity:

η=ν×ρ In the formula η - dynamic viscosity of the sample（mPa.s）

ν - Sample kinematic viscosity（mm2/s）

ρ - Density of the sample at the same temperature as the measured kinematic viscosity（g/cm3）

6.Be sure to change the speed when the motor is running.

7. The connection end face and thread of the connecting screw and rotor should be kept clean, otherwise it will affect the correct connection and stability of the rotor during rotation.

8.When lifting the instrument, hold it with your hand to prevent it from falling automatically.

9.After each use, the rotor should be cleaned in a timely manner (rotor cleaning is not allowed on the instrument), and it should be properly placed after cleaning.

10.Do not disassemble or adjust instrument parts at will, and do not add lubricating oil by yourself.

11. When moving and transporting the instrument, rubber bands should be used to wrap around the pointer control rod, and a yellow packaging sleeve should be inserted to support the connecting screw, and then tightened with screws.

12. Many suspensions, emulsions, polymers, and other high viscosity liquids are "non Newtonian liquids". The surface viscosity of non Newtonian liquids varies with shear velocity and time, so the results obtained at different rotors, speeds, and times are not normal. Therefore, the viscosity values measured by this instrument for non Newtonian liquids can only be used as reference values (generally, the measurement of non Newtonian liquids should be carried out according to the rotor, speed, and duration specified in their measurement requirements, or by comparing the measurement conditions and environment to verify whether their viscosity is qualified).

13. By achieving the following points, a relatively high value can be measured:

1. Control the temperature of the measured liquid.
2. Immerse the rotor in the measured liquid for a sufficient amount of time while maintaining a constant temperature, so that it can match the temperature of the measured liquid.
3. Ensure the uniformity of the liquid.
4. When measuring, try to place the rotor at the center of the container as much as possible.
5. Prevent bubbles from adhering to the underside of the rotor when it is immersed in liquid.
6. Change the rotor or speed to make the reading on the dial slightly higher.
7. Use a protective framework for measurement.
8. Ensure the cleanliness of the rotor.
9. Correct the power frequency according to the correction formula if it is not on time.
10. Strictly follow the operating rules for use.

matters needing attention:

1.This instrument is suitable for use at room temperature.

2.The instrument must be measured within the specified frequency and voltage tolerance range, otherwise it will affect the measurement accuracy.

3.Try to use the bracket to fix the instrument for use, and if handheld operation is required, keep the instrument stable and level.

4.Be careful when loading and unloading the rotor. When installing and disassembling, lift the connecting screw slightly and do not apply too much force. Do not subject the rotor to lateral force to prevent it from bending.

5.After installing the rotor, the instrument should not be placed sideways or upside down.