As we all know,
the vertical centrifugal pump is used to transport clean water and other basic
liquids with physical and chemical properties similar to clean water. It is
suitable for industrial and urban water supply and drainage, pressurized water
supply for high-rise buildings, garden sprinkler irrigation, fire
pressurization, long-distance transmission, and HVAC refrigeration cycle. So the
use of different industries is not completely the same, so we can not choose the
same product when we choose vertical centrifugal pump, so how do we choose
vertical centrifugal pump reasonably?
Reasonable pump selection requires
comprehensive consideration of comprehensive technical and economic indicators
such as pump unit, pump station investment and operation cost, so as to conform
to the principles of economy, safety and applicability. It includes the
following aspects:
1) Water pumps with high efficiency, low noise and energy
conservation shall be selected, and obsolete products are strictly
prohibited.
2) . The pump shall be selected according to the design flow and
the required lift, and considering that the pump output decreases due to wear
and other reasons, the pump can be selected by multiplying the calculated lift H
by a coefficient of 1.05~1.10; The pump with the characteristic curve of
gradually decreasing head as the flow increases shall be selected, so that the
pump can work stably and reliably in parallel; And the operating point of the
water pump should be kept in the high efficiency range, which is not only
energy-saving but also not easy to damage the parts.
3) When there is no
regulating facility in the water supply network, it is better to use the speed
regulating pump set or the rated speed pump set for marshalling operation of
water supply. The maximum water output of the pump unit shall not be less than
the design water supply flow of the community, and shall be checked according to
the fire fighting conditions.
4) . The number of lifting pumps for water tank
and water tower shall be reduced as far as possible, and one for use and one for
standby; When a single pump can meet the requirements, it is not suitable to use
multiple parallel pumps; If multiple pumps must be operated in parallel or
matched with large and small pumps, their models and numbers should not be too
many. Generally, they should not exceed two types, and the lift range of pumps
should be similar; When running in parallel, each pump should still operate
within the high efficiency zone.
5) The design water supply flow of the
variable frequency speed regulating pump (group) shall meet the requirements of
the maximum design flow per second in the domestic water supply system. The
power supply must be reliable (dual power supply or dual circuit power supply);
The working point of the pump shall be selected in the efficient working area of
the pump characteristic curve (Q-H curve), and not in the extension line of the
Q-H curve. The most unfavorable working point shall be designed at the right end
of the efficient section of the pump characteristic curve, that is, the point
where the pump has the largest water output, but the head is low but can meet
the requirements, that is, the intersection point between the low point of the
efficient section of the pump characteristic curve and the pipe characteristic
curve. The working range of water pump speed regulation shall be within the high
efficiency range of water pump as far as possible; The speed regulation range
should be set between 25% and 100% of the water supply of the pump; The
equipment shall have automatic water level control function.
6) The water
pump unit of the domestic pressurized water supply system shall be equipped with
a standby pump. The water supply capacity of the standby pump shall be greater
than the water supply capacity of the largest operating pump. The pump shall be
automatically switched and operated alternately.
7) The voltage of the motor
equipped with the water pump shall be the same, and the power supply system
shall be the same as that of the national grid.
Screw Vacuum Pump in the Use of Pay Attention to Solving Unbalanced Inertial Force
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