Degasser

Content
1. What is degasser?
    1.1 Degasser working principle
    1.2 Degasser function
    1.3 Degasser feature
2. Use of degasser
    2.1 Degassing program
    2.2 Degasser operation
3. Application of degasser
    3.1 Degassing of the liquid phase mobile phase
    3.2 Solvent degasser
    3.3 Membrane degasser
4. How to buy degasser?

Degasser, also known as vacuum degasser, is a device that uses vacuum suction to remove the non-condensable gases contained in the feed liquid. The vacuum degasser can operate effectively even in closed water circulation systems.

The principle of vacuum degasser is based on Henry's law. At a certain temperature, the solubility of a gas in water is proportional to the pressure. At a certain pressure, the temperature of water decreases, and the solubility of gas decreases.

Through the generation of a vacuum, the free gas and dissolved gas in the water are released. The system is discharged through an automatic exhaust valve, and then the degassed water is injected into the system. These low-gas-content waters are unsaturated. It is highly absorbent to the gas and absorbs the gas in the system thus to the gas level balance. The vacuum degasser repeats this cycle every 20-30 seconds.

In other words, part of the liquid in the water circulation system is placed under a vacuum, and the free state gas and dissolved state gas in the released liquid will be released. Afterward, this part of the degassed, absorbent liquid will be injected back into the water circulation system to participate in the cycle. They will reabsorb the free and dissolved gases in the system to reach equilibrium again. After several cycles, the free and dissolved gases in the water circulation system can be removed.

a. Gas removal. The system can remove the free gas and dissolved gas inside the system.

b. Automatic water replenishment. Degasser system can automatically make up water to the system.

a. Shorten the exhaust time after the initial water injection of the heating or cooling system, which is beneficial to the initial commissioning operation of the system.

b. Removal of gases from the degasser system. Anti-cavitation resistance, making the system stable during normal operation. Water pump cavitation, reduce system operation noise.

c. Remove the oxygen in the water, reduce the aerobic corrosion of the system, and extend the service life of the equipment.

d. Removal of gas from water. No gas bubbles are attached to the surface of the heat exchanger, providing thermal efficiency.

e. The working time and cycle of degasser can be adjusted as needed.

f. The capacity of a single applicable system can be up to 500 cubic meters. Multiple units of the system can be used in parallel.

g. The equipment is easy to install, automatic operation, and easy to repair and maintain.

Vacuum degassers can operate automatically according to the user's pre-set degassing program. There are two stages of the degassing process.

The liquid in the system enters the degassing tank. All the gases contained in the liquid will be released and separated from the system through the automatic venting valve at the top of the degassing tank.

The tank is continuously vacuumed to create a negative pressure state so that the dissolved gas in the liquid is released and gathered at the top of the tank, and discharged through the automatic air release valve. At this time, the water inlet solenoid valve opens again and new liquid enters the tank. Those degassed, absorbent liquids are injected back into the system to participate in the cycle and reabsorb the gases in the system.

A. Set the pressure value, which can be adjusted according to the actual test results. Low pressure is 0.05MPa, high pressure is 0.1MPa.

B. Start-up operation.
a. Check the position of each control knob of the control cabinet before powering on, and adjust the position.
b. Turn on the power switch. The degassing tank is in water shortage, and the control system will alarm because of water shortage.
c. Adjust the button position (refer to the product manual). The solenoid valve is energized and opened. When the water level in the tank exceeds the low-level measurement point, the low-level alarm is automatically lifted.
d. Turn the solenoid valve knob to the automatic position. The inlet solenoid valve will continue to be energized and open until the pressure in the tank reaches 0.1MPa when the solenoid valve is automatically closed.
e. Bleed the high-pressure pump.
f. Check and adjust the steering of the high-pressure pump.
g. Turn the knob of the high-pressure pump to the automatic position, then the high-pressure pump will start automatically.

C. Continuous exhaust.
a. When the pressure in the tank reaches 0.1MPa, the solenoid valve will automatically power off and close, while the high-pressure pump starts pumping.
b. When the pressure in the tank reaches -0.05MPa, the high-pressure pump will stop automatically, while the solenoid valve will open the water into the automatic exhaust and delay 0 to 5 minutes, which can be adjusted according to the automatic exhaust situation on site.
c. Cyclic this automatic degassing procedure and uninterrupted exhaust.

D. Timed exhaust. Every 8 hours interval, automatically start degassing program for 30 minutes.

E. When the liquid level in the tank reaches the lowest level, it will automatically alarm. The water inlet solenoid valve opens and the high-pressure pump stops. Until the liquid level exceeds the low-level measurement point, the alarm is lifted. If there are repeated alarms or keep having alarms, you should stop and check. Check whether the water inlet solenoid valve is not sealed tightly, the solenoid valve coil is damaged, or the electric contact pressure gauge is damaged.

F. A necessary function for the automatic control program.
If the pressure inside the degassing tank is between -0.1MPa~1MPa pressure value, it means that the actual pressure inside the tank is higher than the low-pressure value. However, if the pressure is lower than the high-pressure value, the inlet solenoid valve must be continuously energized until the pressure in the degassing tank reaches the set high-pressure value, otherwise, the high-pressure pump will not start.

Gas is generated when the mobile phase is heated, or when different components of the mobile phase are mixed. Gas bubbles entering the pump cause pressure fluctuations, increase noise and lead to burrs on the chromatogram.

The above problems can be solved in the following ways.
a. Re-degassing of the mobile phase.
b. Using a more efficient degassing method.
c. Using a combination of the first two methods together.
d. Change the in-system mixing to out-of-system premixing.
e. The mobile phase used in HPLC must be pre-degassed, otherwise bubbles will easily escape in the system and affect the work of the pump (degasser HPLC).

Common degassing methods include heating and boiling, evacuation, ultrasound, helium blowing, etc. For mixed solvents, if using the pumping or boiling method, it is necessary to consider the change in composition caused by the volatilization of low boiling point solvents.

Helium degassing is one of the very effective degassing methods. Helium gas is slowly driven through the mobile phase to remove dissolved air. If used properly, 80% to 90% of the dissolved gas can be removed within 10 min. Because of the extremely low solubility of helium in the mobile phase, the mobile phase protected by helium degassing can be considered a gas-free dissolved system. The disadvantage is that helium is expensive and increases the cost of the test.

Generally, the gas in organic solvents is easy to remove, while the gas in aqueous solutions is more stubborn. Blowing helium in solution is a fairly effective degassing method, and this continuous degassing method is often used in electrochemical testing. However, helium is expensive and difficult to popularize.

Vacuum degassing is also one of the commonly used degassing methods. The reservoir is pumped into a partial vacuum and the dissolved gas evaporates to form bubbles that overflow, which is second only to helium degassing. Inline degasser is only suitable for the mobile phase after degassing, and for micro degassing during use.

Ultrasonic degassing method means that the prepared flow-connected container is put into the ultrasonic degasser for 10min to 20 min. Although this method only removes 30% of the dissolved gas and sometimes causes an increase in gas solubility, it is still widely used for it is easy to operate and meets the requirements of daily analytical operations.

When using the ultrasonic degasser, the solvent bottle should not be in contact with the bottom or wall of the ultrasonic tank, which may cause the glass bottle to break. In addition, the liquid level in the container should not be too much higher than the water level.

The solvent in the solvent bottle flows through a special tubular plastic membrane inside the vacuum chamber under pump extraction. As the solvent passes through the vacuum tube, the dissolved gas in the solvent will permeate through the tubular plastic membrane into the vacuum chamber. By the time the solvent leaves the outlet of the vacuum degasser, it is almost completely degassed.

Membrane degasser is a hollow fiber membrane component that controls the degassing and gas supply of the rolled body. It has a unique hollow fiber with dense skin that does not transmit liquids, but only gases. It is suitable for liquid degassing (liquid degasser) and gas supply.

The degassed membrane has a dense epidermis that is completely integrated with the inner support layer. It is not a composite structure. This integrated structure not only has excellent performance but also has good durability. By using a hollow fiber degassing membrane with dense skin, condensate generation can be kept to a low level.

If you are interested in our degasser or have any questions, please write an e-mail to [email protected], we will reply to you as soon as possible.