1. Operation steps
Step 1, Please fulfill the pump with water (liquid) before the initial operation, fully open the water inlet and outlet valve and close the air inlet valve and pressure meter at the outlet and turn on the power supply shortly to check if the direction of rotation of the pump is right. Please always close the air inlet valve before turn on the power supply.
Step 2, Gradually reduce the inlet valve until the vacuum gauge shows negative pressure at -0.01Mpa. Then open the air inlet valve, open the check valve of the outlet pressure gauge and adjust the outlet line control valve until the outlet pressure is reached which is 0.4MPa.
Step 3, Slightly adjust the control valve, air inlet valve on the inlet line and the valves on the outlet line so that the water flow, gas flow and outlet pressure can reach a predetermined value. The gas flow rate is approximately 7-8% of that of water flow. For example, if the water inlet is 301L/min, then the gas inlet is 2.4-3.01L/min; if the water inlet is 501L/min, the gas inlet is 4-5.0L/min.
Step 4, When the water inlet, air inlet and outlet pressure reach the predetermined value, the machine can operate normally.
Step 5, Please close the air inlet valve first when shutting down the pump.
1) As the amount of air inlet increases, the discharge flow rate and pressure will gradually decrease. When the air inlet exceeds a certain limit, the water flow will stop, that is, the pump lost its function.
2) When selecting a gas-liquid mixing pump, please refer to the pump performance parameter table. The discharge pressure of the pump is different depending on the application. The pressure is generally set to 2~3kgf/m with the ozone gas mixing. The pressure is generally set to 3.5~4kgf/cm with the dissolved air flotation and oxygenation treatment. When the gas injection ratio is 7-8%, please choose a pump that is larger than the actual discharge flow.
3）The pressure at which the micro bubble is produced usually not more than 4kgf/cm. When the pressure exceeds 4kgf/cm, there will be no difference with the dissolution and diameter of bubbles, but it will reduce the amount of air dissolved liquid discharge and increase the power consumption of the pump.
4) Setting of gas injection amount:
The rate of saturated dissolution of air in the water at normal pressure is about 3%. With gas-liquid mixing pump, the amount of air that is injected into the water should be greater than that. We suggest that the air inlet should be the equivalence of 7-8% of the water flow but not exceeding 10%. The air that is not dissolved into water will be in the water in the form of big bubbles which will evolve into airlock at pressure releasing valve and affects the production of micro bubbles. We suggest a gas-liquid separation tank should be installed before the pressure release valve so as to discharge the extra air. We usually determine the volume of the separation tank based on the flow rate, but we can also determine the volume of the tank by the pump's inlet diameter.
5) In order to ensure the air absorbing effect, the gas suction nozzle is generally used at the suction port of the pump. The gas nozzle introduces gas into the vicinity of the impeller and by the rotational force of the impeller, smoothly introduces gas and liquid into the flow path of the pump. The use of a gas nozzle ensures stable gas inhalation and efficient dissolution. A check valve and an additional check valve can work together to basically prevent the reverse flow. When being manually operated, there is no need of both check valve and a solenoid check valve. Please operate the machine according to the instruction manual.
6) In order to ensure the production of micro bubbles, the design of the discharge pipeline behind the pressure releasing valve should abide by the following items:
A. The diameter of the drain pipe should be the same as or larger than the outlet diameter of the pump.
B. The front end outlet of the drain line needs to be placed laterally or upwards, and cannot be set downwards.
C. The diameter of the hole that releases the micro bubbles should not be less than 10mm.
D. The length of the drain line after the outlet valve is generally set to 0.5-1m, and the pipeline after the outlet valve should be as short as possible.
E. The gas flow meter is used to adjust and control the amount of gas inhaled. The material of the gas nozzle and the gas flow meter is generally determined by the medium of gas and liquid, and the ozone device is required to be made of stainless steel.
7) Suction line
A. The diameter of the suction pipeline is generally the same as the suction diameter of the pump or larger than the suction diameter of the pump.
B. In the case of inhaling gas with negative pressure, the suction diameter needs to be fined one level, but not too thin.
C. When the water level is lower than the center height of the pump, a bottom valve should be provided at the lower end of the suction pipe.
D, The suction line should be provided with a filter or Y-type filter (60 mesh) to avoid damage to the pump impeller caused by solids in the liquid.
Please always turn off the power when servicing the pump, as the pump may suddenly operate and cause some damage to the maintenance personnel.
Things needed to be aware of during daily inspections:
1) If there is significant abnormality in pressure, voltage, vibration and noise, etc., please shut the pump immediately for inspection and maintenance because these abnormalities are the precursor to the accident. To avoid any of these situations happening, a standby pump is recommended.
2) The allowable temperature rise of the bearing is not more than 80 degrees. The temperature of the outer cover of the motor is normal when it can be touched by hand. Otherwise, please stop the inspection.
3) If the mechanical seal is normal, the leakage amount should not exceed 3ml per hour. If the leakage exceeds this amount and gradually increase after normal operation, please stop the inspection immediately.
4) If the installation and the connection are normal, but the vibration is strong during operation, it means that the pressure of the pump is too large or the base nut is loose, so it is necessary to shut down the machine and start the inspection.
4. For the operation of the pump, please refer to the following items
1) If the pump is operated above the specified pressure (head), it will operate overloadly, so the motor will burn out.
Special reminder: Do Not Close The Valve On The Discharge Line During Operation!
2) The gas-liquid mixing pump will have some metal sounds when it is running at high pressure, which is an inherent characteristic of pump, not an abnormality.
3) Frequent start and stop will cause damage to the pump. It is recommended that if the motor power ≤ 4kw, the on & off frequency should be no more than 100 times per hour if electric power > 4kw, it should not be more than 20 times per hour. If the startup is found to be too frequent, the control device must be adjusted to reduce the start and stop frequency. At this point, it is necessary to check the installation situation.
4) Always cut off the power connection of the pump when the power is off, to prevent the pump from suddenly starting when the power is turned on.