Controlling the characteristics of the processpumping of liquid in modern pumps is provided in manual and automatic modes. Depending on the requirements for operation, it may be necessary to take account of certain parameters. For example, the user can adjust the feed volumes and the intensity of the function. In this case, there are separate types of equipment specifically designed for point-like maintenance of certain media. These include dosing pumps used in the food, pharmaceutical and chemical industries.
Dosing pump features
Dosage units provide the possibilityvolumetric pressure transfer of liquids, suspensions and emulsions. Most of these pumps can serve both neutral and aggressive environments. For this reason, their use is widespread in the chemical industry. Depending on the characteristics of the material used in the flowing part, the specific purpose of the equipment is determined. The main difference from traditional household units is that the metering pumps allow to regulate the pressure level from the exit point to the input of the working medium. In this case, the absolute value of the inlet pressure exceeds the analogous parameter of the saturated vapor of the pumped liquid. Among the main technical and operational characteristics of such equipment is the ability to work with media of a certain kinematic viscosity and diameter of the passage of the nozzles.
This kind of dosing pumpis designed to work with liquids and pasty substances. The principle of operation is based on mechanical action on the working channel, which is most often represented by a strong, but elastic tube. That is, in the process of working on the hose with the medium is a mechanical pressure, as a result of which there is a pushing of the liquid to the outlet. As a physical activator, rollers around the circumference are used. By design, dosing pumps of this type are a device including elastic pipes and a hose with a set of rollers. The infrastructural part is also provided by a track in which the pipe line is laid. It is in him and the physical effect.
This is a volumetric pump in which the function of theThe organ is executed by a flexible plate fixed at the edges of the structure. To a certain extent, it acts as a piston. The membrane flexes during operation, which leads to a displacement of the liquid. In this case, the force effect can be rendered in different ways. For example, the use of mechanical drives, hydraulics and pneumatic devices is practiced, which deform the plate by changing the pressure in the working cavity. Due to the lack of gears and motors, the metering pumps are considered the safest and most reliable. This is especially important in the maintenance of flammable liquids, since the function of the unit has no prerequisites for the formation of a spark.
This is a kind of piston hydraulic machines,working on the basis of reciprocating motions. Valve distribution system does not allow the use of such units for reverse action, which distinguishes them from other volumetric devices. Reverse movement of the piston on the pipeline leads to the closing of the valve, which prevents the leakage of the medium into the channel. At the same time, the valve on the discharge side opens, and through it the liquid leaves the receiving area. During operation, the plunger metering pump provides an uneven flow velocity, which causes its main drawback. The jumplike effect is compensated in various ways, including by introducing several piston elements into the structure.
Marking of units
If the structural design of the unitsare carried out in accordance with the requirements for a specific form factor, then in terms of functional content and means of controlling mechanisms, manufacturers develop common standards. Thus, the dosing pump ND provides manual control of the transmission of liquid from the moment the unit stops. If the system is provided with the possibility of automatic and remote control, the equipment is assigned the designation NDE.
Also, manufacturers indicate the dosing index,which on average is 1-2.5. There are also devices that do not have this indicator at all. As a rule, models with an initial index do not have a heating jacket, and the highest level of dosing accuracy is characterized by the presence in the design of the approach for the gate or rinsing liquid. This classification also applies to all types of aggregates. For example, the metering pump plunger ND can have both the first precision index and the second.
Reviews of manufacturers
Dosage models in the pump familyequipment occupy a separate niche due to the specifics of their application. This is not a household segment, so they are not widely used by manufacturers themselves. The development in this direction is carried out by large specialized companies, among them Etatron and Grundfos. In the assortment of the first manufacturer, the eOne Basic modification became popular. This membrane unit, whose users note the presence of a thoughtful intelligent control system with the possibility of high-precision power regulation. Equally well represented are metering pumps Grundfos, and in particular diaphragm representatives of the DME series. The owners of such equipment emphasize the reliability, the successful performance of ball valves, as well as the function of the electronic unit, which allows to regulate the accuracy of dosing.
Segment of dosing pump equipmentcan be attributed to industrial, because such devices are more often used in enterprises, in service organizations, etc. This explains the high requirements for the execution of the structural part. Reliability, safety and stability are the main qualities that modern dosage systems should possess. Pumps of this type operate in a mode of intensive operation, therefore, manufacturers aspire to increase the resource of the element base. Among the negative factors, not only ordinary wear and tear of mechanical parts is distinguished. For example, membrane units have practically no rubbing components. But the flowing part, which is in contact with aggressive media, must be protected from chemical attack.