First, to confirm the environmental conditions of the vacuum pump of water selecting ring?
Including the requirements of atmospheric pressure, ambient temperature, air corrosivity, relative humidity, dangerous area level, dust prevention and waterproof.
Second, to confirm the medium property of the vacuum pump of water selecting ring?
It includes the name, temperature, saturated steam pressure, density, viscosity, solid particle diameter and content, gas content, flammability, toxicity, corrosiveness and volatility of the medium to be pumped.
Third, confirm the operating conditions of the vacuum pump of water selecting ring?
This refers to the absolute liquid level pressure at the suction side, the liquid level pressure at the discharge side, intermittent or continuous operation, fixed or movable position, and the convenience of installation and maintenance.
Fourth, what is the material of the overflow part of the water ring vacuum pump?
1. The corrosiveness of the medium to be pumped,
The anti-corrosion performance of the pump overflow parts can meet the use requirements, and the high anti-corrosion performance cannot be pursued, otherwise, the purchase cost of the pump will be greatly increased.
2. Whether the medium to be pumped contains solid particles,
Because the hardness and content of the solid particles are directly related to the durability of the overflow parts of the vacuum pump.
3. Temperature (pressure) of the medium to be pumped,
The higher the temperature (pressure) of the medium is, the higher the material strength of the pump’s overflow parts should be. Generally, when the temperature is more than 250 ℃, steel castings or steel pieces shall be selected.
4. Medium with requirements of hygiene level or no pollution,
Select the appropriate overcurrent assembly material. In addition, the pump structure should be easy to clean.
Fifth, what are the performance parameters of water ring vacuum pump?
1. calculation method
(1) . flow: it is directly related to the production capacity and conveying capacity of the whole plant. For example, the normal, minimum and maximum flow of the pump can be calculated in the process design. When selecting the pump, the maximum flow shall be taken as the basis and the normal flow shall be considered. In the absence of the maximum flow, 1.1 times of the normal flow shall be taken as the maximum flow.
(2) . head: generally, the head after enlarging 5% – 10% margin shall be selected. Special attention: the flow of centrifugal pump, especially the head margin should not be too large, otherwise, cavitation may occur when the pump is working, resulting in the flow and head can not meet the requirements. Once this happens, generally, remedial measures can be taken to cut the outer diameter of impeller or turn down the outlet valve of pump.
(3) Power: generally, the power form and size of the pump belt shall be selected by the manufacturer and marked in the product sample.
Check whether Cavitation allowance and required Cavitation allowance of vacuum pump are matched. When it can’t be satisfied, effective measures should be taken to achieve it.
2. Analogy and test
When the resistance value of vacuum pump pipeline system can not be calculated accurately, the performance parameters such as flow and head of the pump can be determined by analogy or test.
Sixth, choose the installation type of water ring vacuum pump?
According to the pipeline layout and installation site, horizontal, direct, vertical and other types (angle type, double type, detachable type, right angle type and variable angle type) shall be selected.
Seventh, determine the number and standby rate of water ring vacuum pump?
Generally, only one vacuum pump is used for normal operation, because a large vacuum pump is equivalent to two small pumps working in parallel (i.e. the same head and flow), and the efficiency of the large pump is higher than that of the small vacuum pump, so from the perspective of energy conservation, it is better to choose one large vacuum pump instead of two small vacuum pumps, but in case of the following situations, parallel cooperation of two vacuum pumps can be considered:
(1) The flow is very large. One pump can’t reach this flow.
(2) For the vacuum pump requiring 50% standby rate, it can be configured as two for use and one for standby.
(3) For some large vacuum pumps, the vacuum pump with 70% flow requirement can be selected for parallel operation without standby vacuum pump. When one vacuum pump is overhauled, the other vacuum pump still bears 70% of the delivery capacity of production.
(4) For the vacuum pump that must be operated continuously for 24 hours, one shall be operated, one for standby and one for maintenance, totaling three. If necessary, it can be selected with the assistance of the vacuum pump supplier.
These are the selection steps of water ring vacuum pump. did you learn?