Pipelines for various purposes inevitably must have technological units in which measurements are made of the medium served. This applies to traditional water pipelines and gas infrastructure, as well as to specialized industrial complexes working with special chemical liquids. In all cases, technologists provide for equipping the circuits with special flow meters. One of the most attractive from the point of view of operational characteristics of the elements of such equipment is a Venturi nozzle, which is built in at a certain measuring point. This component has many advantages, but when choosing a specific model, the nuances of use should be taken into account.
Nozzle Overview
The main function of this nozzle is to measure the environment that the target water supply services. At the same time, the feature of the device is not so much the ability to contact with liquids of different properties, as structural advantages. The fact is that the nozzle, or venturi, is able to maintain an optimal pressure indicator at the time of passage of the medium. That is, the narrowing of the channel, of course, affects this parameter, but not as much as in the case of other types of flow meters.
There is another important feature. The fact is that the quality of the measurement of the volumes of the passing fluid is often affected by the diameter of the channel, which is a source of medium relative to the measuring device. During operation, the Venturi nozzle practically does not change the measurement accuracy depending on the parameters of this channel.
Device
This is a small device in the form of a pipe, the device of which provides for the presence of technological sections designed for measuring operations. As a rule, the middle, that is, the central part of the nozzle, is pulled by a clamp, from which a special chamber for measuring, and also an opening for taking pressure, departs to one side. On the other hand, the shape of the tube goes into a cone and forms a neck. There are several holes for pressure selection, as well as a diffuser. Typically, the jet pump is connected on this side either directly or through special plumbing fixtures.
Among the structural advantages of this product, experts note the effectiveness of work in the cramped conditions of the pipeline. However, there is a significant plus for inexperienced masters. It consists in a simplified model of nozzle installation.
How does a venturi nozzle work?
The device was named after the Italian scientist precisely for the reason that he discovered the effect of reducing pressure when the working medium passes through a narrowed area. It is on this principle, supplemented by Bernoulli's law, that such tubes work. In practice, this means that the liquid passes the narrowed area, during which pressure is sampled in special annular chambers that supply the Venturi nozzle. The principle of operation also involves the interaction of the exhaust channels with direct measuring instruments. For accurate measurement, in particular, a pressure gauge is used, which can be presented both in the form of an analog device and a digital apparatus.
Specifications
The main criterion for the selection of such pipes is a characteristic of the diameter. The most common formats range from 6 to 12 mm. There are also large sizes that should be selected for specific pipelines. At the same time, it is possible to use adapters of a suitable standard size, so strict fitting to a specific pipe is not so important. In addition to the diameter, the material of which the Venturi tube or the measuring system of fittings as a whole is of great importance. Usually, stainless or carbon steel is used as the base. However, operational and protective properties are largely determined by the type of coating. To ensure longevity, experts recommend contacting models treated with enamel or a primer that protects, among other things, from chemical influences. If we are talking about installation in industrial channels, then the best solution in terms of reliability would be galvanized galvanized coatings.
Varieties
The main differences are structural in the sense that individual technological parts have a special design. For example, nozzles are used in which a cast conical part is provided without treatment. Such models are produced by injection molding using special sand matrices, and only the part and the neck are curved. A more complicated modification is the model, which also provides for the preliminary processing of the inlet sections, with which the jet pump interacts in different versions. In this case, the central base can be performed without special processing.
Fundamental differences from the above types has a device manufactured not by injection, but by welding. In this case, the conical part can be implemented in both straight and rounded shapes.
Fields of application
Design features are due to non-standard ways of using the nozzle. In particular, valves of this type have found application in injection units that operate in conjunction with the aforementioned jet pumps. Such mechanisms are used to compress gas mixtures, liquid vapors, as well as for their subsequent shipment to places with high pressure. Not without such a nozzle and gas cleaning system in some variations. For example, a high-speed gas scrubber is equipped with a nozzle, which filters the served mixtures from submicron and micron particles. Devices of this type are also used in some thermal and steam boilers, but mainly from the industrial sphere.
Pros and Cons of Venturi Nozzle
The undoubted advantages of valves operating on the Venturi effect include the possibility of installation in nodes with changing parameters of the supply channels. However, for the full use of this advantage, appropriate adapters should be prepared initially. For example, if a Venturi nozzle is selected for a pumping station operating at different times of the year, then depending on hydraulic requirements, the volume of fluid supply can change - accordingly, the settings of the supply source are also adjusted.
As for the disadvantages, they boil down to the fragility of the use of pipes that do not have a high-quality protective coating. On the other hand, models with modern surface treatments are much more expensive.
Conclusion
Modern pipelines, coupled with pumping stations, are actively being transferred to automated means of monitoring and control with the introduction of electronic remotes. In some functional parameters, the operators of such installations also monitor the indicators of measuring equipment.
Perhaps the Venturi nozzle is one of the few devices in its class in which operational efficiency is based precisely on the physical principle of control. The technique of integrating such products into the structure of pipelines determines the accuracy of measurements and the minimum negative impact on the functioning of the main channel. Another thing is that in order to maintain optimal performance, regular maintenance of the measuring units is required.