Gas pipeline infrastructure includes a wide range of control devices. Most of them focus on ensuring the safe operation of the system and the ability to control individual operational parameters. One of the most important devices of this type is the automatic gas pressure regulator.
The principle of operation of the device
The work process is carried out due to the functions of two parts of the gas fittings - the performing mechanics and the regulator itself. The first part acts as a sensitive element, thanks to which such devices can in principle be considered automatic. The executive bodies of the gas pressure regulator in a constant mode compare the current indicators of the serviced environment and the standard operating values that were originally set by the operator for a specific working session. Further, when a discrepancy is detected in the indicators, the same mechanism generates a signal for the regulatory system, which corrects the valuepressure, increasing or decreasing it. Moreover, the way of influencing performance can be different - it depends on the energy environment of the power supply. For example, the potential of the same gas or a charge from an external source - hydraulic, thermal, electrical, etc. can be used.
There are also models that implement the direct principle of regulation. That is, a sensitive or executive mechanism is responsible for both comparing the target indicators of the system and for correcting them. Such devices, in particular, include spring-loaded gas pressure regulators. The principle of operation of such fittings is to control the diaphragm, which mechanically affects the state of the serviced system. Typically, such models are used in gas distribution networks that require a fast and direct control mechanism.
Rebar design
The main elements of this type of regulators include valves that are used in different forms. For example, this fitting can be valve, diaphragm, hose and disk. There are in some way combined gas pressure regulators, in the design of which saddle and valve gates are used. Among the advantages of such devices, experts attribute the high tightness of the sealing system. For pipelines with high throughput, double-seated valves are used, in which the area of the flow section is larger than that of other regulators. At large stations, shutter gates have also become widespread. They work in two stages and requireusing external energy sources, but they are reliable when controlling large volumes of gas flow.
Membranes are used as a sensitive organ. Some systems assume their use as drive devices. The membrane itself can be corrugated or flat, but in both cases, the rigidity and ability to withstand various loads varies widely.
In accordance with technical standards, the device of gas pressure regulators with shut-off and control elements must meet the following requirements:
- The dead zone of operation in its value should not exceed 2.5% of the level of the maximum outlet pressure.
- The proportional band for bottled and combination regulators should also not be higher than 20% of the upper outlet pressure limit.
- In conditions of sudden pressure drops in the circuit, the time of technical control transition should not exceed 1 min.
Varieties of technical performance
Regulators for gas environments are classified according to several technical and structural features. In particular, the division concerns the number of reduction (reduction) stages, the complexity of the mechanical design and the way the output pressure pulse is taken.
As for the first feature, there are one- and two-stage models that differ in consumption characteristics. For example, a gas pressure regulator for a home withwith a flow rate of no more than 25 m3/h is more likely to have two reduction stages. This scheme of operation is distinguished by a higher stability of control and multi-level security, implemented through auxiliary components. In systems with increased gas consumption, single-stage devices are more often used.
In terms of design complexity, simple and combined regulators are distinguished, which can also be divided according to the set of functions. In the first case, only the task of reducing pressure is performed, while in the second, possibilities are also provided for noise suppression in the pipeline, valve protection and filtration. According to the pulse sampling system, gas pressure regulators with direct control of output indicators can be divided, and devices with external connection of sensitive elements. The main problem of using the second sampling principle is the obligatory observance of the condition for maintaining the stability of the flow on the circuit under study, otherwise the data will be incorrect.
Household and commercial gas pressure regulators
Structural, functional and ergonomic execution of shut-off valves ultimately comes down to the requirements of a particular application. The emphasis is on direct operating parameters, including outlet pressure, measurement ranges, flow rates, etc. Thus, gas pressure regulators for domestic networks, as a rule, are characterized by low throughput and a modest range of possibilities forsettings. On the other hand, such fittings are focused on safety and ease of use. In practice, household regulators are used in gas supply systems for boilers, stoves, burners and other home appliances.
Industrial and commercial applications place higher demands on gas controls. Devices of this type are distinguished by extended ranges of output and inlet pressures, accurate settings, higher throughput and additional functions. Similar models are used by gas services that control the supply of social facilities, catering, industry, engineering, etc. It has already been noted that there are different regulators in terms of the complexity of the design. But this does not mean that in the industrial sector, for example, only multifunctional combined devices are used. The simplest controls can be useful in factories due to their high reliability and maintainability.
Gas reducer with pressure regulator
The reducer is an autonomous device designed to control the pressure of the gas mixture at the outlet of any container or pipeline. The main classification in this case involves the division of regulatory nodes according to the principle of operation. In particular, reverse and direct devices are distinguished. The reverse action reducer works to reduce the pressure as the gas escapes. The design of such devices includes valves, chambers for buffering the mixture,adjusting screw and fittings. Direct action means that the regulator will work to increase the pressure when the gas is released.
Reducer models are also distinguished by the type of gas served, the number of reduction stages and the place of use. For example, there are gas pressure regulators for cylinders, pipe networks and ramps (burners). In the case of cylinders, the type of gas will determine how the device is connected. Almost all models of reducers, except for acetylene ones, are connected to cylinders by means of union nuts. Devices working with acetylene are usually fixed to the tank with clamps with a stop screw. There are also external differences between the gearboxes - this can be a color marking and an indication of information about the working mixture.
Static and astatic regulators
In static systems, the nature of regulation is unstable in places of direct mechanical interface with the working medium and shutoff valves. In order to increase the stability of such a regulator, an additional feedback is introduced that equalizes the pressure values. Moreover, it should be noted that the actual pressure value in this case will differ from the standard one until the nominal load on the sensitive element is restored.
The traditional version of the static gas pressure regulator provides its own stabilizing device in the form of a spring - for comparison, other versions use a compensating weight. During the working moment, the force thatdevelops a spring, must correspond to the degree of its own deformation. The greatest degree of compression is obtained in situations where the membrane completely closes the regulating channel.
Astatic regulators at any load independently bring the pressure indicator to the desired value. The position of the regulatory organ is also restored. However, the executive mechanics, as a rule, does not have a clear position - at different moments of regulation, it can be in any position. Astatic control devices are more often used in networks with a high ability to self-levelling performance.
Isodromic Throttle Regulator
If a static pressure control system can be characterized as a hard-feedback model, then isodromic devices interact with elastic recovery elements. Initially, at the moment of fixing the deviation from the set value, the regulator will take a position that corresponds to a value proportional to the deviation from the norm. If the pressure does not return to normal, the gas valve will move towards compensation until the indicators return to normal.
From the point of view of the nature of operation, the isodromic regulator can be called a middle device between astatic and static models. But in any case, there is a high degree of independence of this regulatory mechanics. There is also a kind of isodromic reinforcement with advance. This device is different in that the displacement rate of the executive body initially exceeds the rate of pressure change. That is, technologyworks ahead of the curve, saving time to restore the parameter. At the same time, pre-regulators draw more power from an external source.
Now we can move on to the consideration of specific models of gas pressure regulators. An overview of the best representatives of the segment is presented below.
Regulator manufacturers
Device for controlling and controlling the flow of gas mixtures in Russia is widely represented by both domestic and foreign manufacturers. In particular, the Gazapparat plant offers high-precision regulators of the RDNK series, which stably maintain performance in the system, regardless of the activity of gas consumption. Another manufacturer of high-quality devices for regulating pressure in gas pipelines is the Metran enterprise, which develops control and measuring systems together with a large foreign company Emerson. This product is used in industry and households. For example, gas services employ 1098-EGR series systems in managed farms, which are characterized by fast response, accurate parameter settings and high productivity. Basic modifications are quite suitable for gas fuel supply lines to network and local intake points. The GasTech enterprise has a comprehensive approach to the tasks of controlling fuel and gas consumption. The specialists of the enterprise develop individual solutions for servicing gas installations of various types, regardless of their conjugation with other equipment.
Operationregulator
There are several connecting holes of different diameters on the body of the device. The configuration of the connection system should be selected based on the specific operating conditions. The most common channel formats are considered to be in the size range from 0.25 to 1 inch. These connections are suitable for basic fittings and adapters connected by means of rotating washers.
After making sure that the regulator can be introduced into a specific system, you can proceed to the direct installation. It is performed according to the following instructions:
- Include the valve in the working circuits, checking for the presence of gas. Close the valve completely and remove the plug to protect the shut-off valve, if any.
- Slowly pull back the cocking handle. The stroke should be small - about 10 mm.
- Cock the second stage, but gradually, so that there is no gas spasm. If possible, a small leak can be left through the shut-off valve.
- The shut-off valve plug is put back.
- Slowly close outlet valve after repairing process leaks.
During the installation process, you can make basic settings for the gas pressure regulator for several parameters: flow, cutoff position, maximum pressure, etc. As a rule, specific values are taken either from the design data or from the device manufacturer's passport. It is recommended to make settings with deviations of no more than 10% from those set indocumentation. A socket wrench is used to control the working pressure. By turning the tip of the plug with it, you can increase or decrease the specified value.
Conclusion
The use of control and, in particular, control valves in the operation of gas equipment is an extremely important measure not only from the point of view of fulfilling technological tasks, but also as a condition for ensuring safety. At large enterprises, stations and complexes with a hydraulic mode for servicing gas distribution networks, control devices are installed at several points, automatically controlling the processes of movement of working mixtures.
What is the need to use gas fittings in practice? The decrease and increase in pressure affects the condition of equipment and pipeline networks, which is especially important given the explosive nature of gaseous media as such. Also, regulation is required as a condition for compliance with the established volumes of distribution of mixtures through different channels within the same system. Management in this sense means controlling the intensity of gas movement in accordance with given needs and operating conditions.
Of course, not only for the needs of industry, pressure regulators are used in equipment that serves gas mixtures. Both compact burners and boilers with boilers for this type of fuel also require the connection of control devices. Another thing is that there are different schemes and configurations for controlling gas flows. Therefore, there are manyvarieties of gearboxes and regulators, the designs of which are focused on the needs of a particular user.
