Method for high-precision on-line proportional mixing of plurality of liquids

Abstract

The invention discloses a method for high-precision on-line proportional mixing of a plurality of liquids. With the method provided by the invention, a reflux bypass is additionally arranged at the tail end of a conveying main pipeline in each liquid output unit; a reflux proportion adjusting valve is arranged on each reflux bypss; a liquid flowmeter is arranged at the tail end of each output pipeline; an output proportion adjusting valve is arranged at the front end of each liquid flowmeter; when conveying of to-be-mixed liquids is started, the reflux proportion adjusting valves in liquid output units are adjusted to maximum opening, and the output proportion adjusting valves are adjusted to preset opening; real-time flow values of liquids are acquired and adjusted by comparing with a preset flow value; when the real-time flow values of the liquids are adjusted to a preset flow range, the real-time flow ratio of the to-be-mixed liquids is calculated according to a predetermined mixingtarget and adjusted again by comparing with a predetermined mixing proportion value; thus, on-line high-precision mixing of a plurality of liquids is realized, and extensive application range is achieved.

Description

technical field [0001] The invention relates to a multi-liquid on-line proportional mixing system, in particular to a method for high-precision on-line proportional mixing of multi-liquids. Background technique [0002] With the gradual development of the fire protection industry, there are more and more types of foam liquids suitable for Class A and Class B fires. When in use, the foam liquid and water are mixed according to a certain ratio, and when the foam gun or foam gun is sprayed, air is sucked in to form foam, which is sprayed on the surface of the burning object to form a covering layer, so as to achieve the purpose of fire extinguishing. The foam proportional mixer is the "nerve center" of the foam fire extinguishing system, and its working performance is directly related to the success or failure of the foam fire extinguishing system in extinguishing fires. In addition, in oil refining, chemical, pharmaceutical, beverage and other industries, the mixing of variou...

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Problems solved by technology

[0003] In the prior art, there have been reports on control methods and system technologies for proportional mixing of various liquids. For example, a proportional mixing system and method are provided in Chinese patent application CN201380010494.5. The proportional mixing system is to mix the main liquid and A system in which the slave liquid is mixed according to a predetermined mixing ratio. The main liquid is delivered to the mixer from the main liquid pump through the main liquid pipeline. The liquid pipeline is sent to the main liquid pipeline and added to the main liquid, although the invention can recognize the error accumulated retrospectively by using the accumulated flow of the main liquid and the secondary liquid, and can Keeping the mixing ratio of the flow rate of the main liquid and the secondary liquid at the predetermined mixing ratio as the target realizes the online proportional mixing of various liquids, but since the main liquid and the secondary liquid are both delivered and adjusted by the pump, when The delivery capacity of the liquid delivery pump is greater than the mixed flow rate. When the flow demand is less, the pressure of the delivery pipeline will increase, which will cause the pressure relief valve to open and release part of the flow to achieve balance, while the pressure relief valve can only adjust the pressure. , and cannot obtain a balanced flow rate, which makes it difficult to guarantee the mixing accuracy of this system, especially when the ratio value changes greatly, and the flow rate changes from large to small liquids, this phenomenon is more obvious; especially for some low-speed, For pumps with large internal leakage, when the flow rate changes in a large range, the accuracy of the mixing ratio cannot be guaranteed at all.

[0004] Generally speaking, the single-channel control, that is, the method of controlling the flow only on the delivery pipeline, has the disadvantages of insufficient control range and limited accuracy improvement

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