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Parallel operation of speed regulating pump and constant speed pump

Parallel operation of speed regulating pump and constant speed pump
! Two water pumps of the same model! One fixed speed and one speed regulation are operating in parallel
When the speed regulating pump and the constant speed pump work in parallel! There are usually two situations: one is the speed of the variable speed pump in%! And constant speed
The pump speed% # is known! Find the parallel operating point "If%! 1% #! Follow the steps shown in Figure! 3 # # to solve $If%!"% #!
According to the picture! Solve the steps shown in 3 # 0“
Another scenario is to know the speed% # of the constant speed pump and the total flow rate of parallel operation!! Find the speed% of the speed regulating pump! This type of
The problem is quite complex! The operating point value of the constant speed pump%! $! # $&# The operating point value of the speed regulating pump%! #! # #& And speed regulation
Pump speed%! "It's also quite complex to solve this situation directly! We need to use the method of bending characteristic curve to solve it."
The solution steps are as follows, as shown in the figure! 3 # D&)
%& Draw the% of two water pumps of the same model! 0 Characteristic curve! And press # 1 #) * O1AJ#
AJ draws 64 paragraphs
Pipeline characteristic curve! 0 $&AJ $and according to- In! Determine 9 points on the 0 $&AJ curve$
%#&The vertical axis of 9 o'clock is the height of the pressure measuring tube # A at 6 o'clock$
%$&by $&AF11AF! #! Draw below the horizontal axis! 0 $&AF curve! From the constant speed pump under corresponding flow conditions
Subtract $&AF from the head characteristic curve! Get the bending characteristic curve% of the constant speed pump! 0 #&T$
$Leading horizontally from 9 o'clock to the left
Line! Intersection curve%! 0 #&T$
At point #$
%0&Draw a vertical line from point # upwards! Characteristic curve of water pump%! 0 Click here Point is the working condition of the constant speed pump
The horizontal axis of the point represents the flow rate of the constant speed pump! The vertical axis represents the head of the constant speed pump$
%5&The flow rate of the speed regulating pump# 1- V! $! Head of speed regulating pump # # 1 # AO $&@ A1# AO1@A !
#
#
$Root

According to%! #! # #& You can draw the operating point 3 of the speed control pump on the graph$

%%&Press? one
##
#
#
! Get it? Value! Press # 1# Draw a parabolic curve with a similar working condition passing through 3 points and an equal efficiency curve of%
Line&! Compared to the original fixed speed pump%! 0 Curve intersection at @ point%! X # # X&“
#Determination of the number of speed regulating pumps during parallel operation
When multiple water pumps are working in parallel in the pump station! The proportion of configuration between speed regulating pumps and constant speed pumps should be maximized to fully utilize the advantages of each speed regulating pump
The principle is that it can still work within the high efficiency range during speed regulation operation“
For example, a certain pumping station requires a water supply of! @! And! #&! @&! $! We plan to use three water pumps of the same model to work in parallel! his
There should be a speed regulating pump in the middle to adjust the flow rate. If! @ is close to! $, you can use a one adjustment and two setting scheme configuration. At this time! Pump station
The water supply is! @! Two constant speed pumps, each with a flow rate of! 4! The flow rate of the speed control pump is! 7% as shown in the picture! 3 #? As shown&! Due to! 7 Comparisons
Big! Therefore! Both the constant speed pump and the variable speed pump can work in the high efficiency zone. If the output of the variable speed pump is very close at this time
Water volume@ It's very small! Its efficiency! The value must be very low! Unable to achieve energy-saving effect "Therefore, a certain scheme of secondary adjustment should be adopted"
At this moment! When the water supply of the pump station is! @! A constant speed pump for supply! 4! Two speed regulating pumps, each supplied! 4O! seven
#
! This! 4O! seven
#
The value can be controlled within the high efficiency range of a single pump“
Picture! Diagram of parallel operation of a certain water pump for 3 # D adjustment! 3 #? Three speed regulating pumps of the same model # are working in parallel with fixed speed pumps
Obviously! In actual engineering! When multiple pumps are working in parallel! The more speed regulating pumps there are, the better! This is because the speed control pump station
More numbers! The smaller the speed range of each pump! The decrease in efficiency is smaller, but it's obvious! The more variable speed pumps there are! Engineering
The cost will increase! Therefore! Reasonable determination of the number of speed regulating pumps“