The gas pipeline infrastructure includes a wide range of regulatory 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 gas pressure regulator, which operates in automatic mode.
The principle of operation of the device
The working process is carried out due to the functions of two parts of gas valves - performing mechanics and the regulator itself. The first part acts as a sensitive element, due to which such devices can, in principle, be considered automatic. The executive bodies of the gas pressure regulator in a continuous mode compare the current parameters of the medium being serviced and the standard operating values that were originally laid down by the operator for a specific working session. Further, when a discrepancy is found in the indicators, the same mechanism generates a signal for the regulatory system, which adjusts the pressure value by lowering or increasing it. Moreover, the method of influencing the performance indicators can be different - it depends on the energy environment of the food. For example, the potential of the same gas or a charge from an external source can be used - hydraulic, thermal, electric, etc.
There are models in which the direct principle of regulation is implemented. That is, the sensitive or actuator is responsible for comparing the system’s targets and for correcting them. Such devices, in particular, include gas spring pressure regulators. The principle of operation of such valves is to control the diaphragm that mechanically affects the state of the serviced system. Typically, such models are used in gas distribution networks, which require a quick and direct control mechanism.
Reinforcement design
The main elements of regulators of this type include valves, which are used in different types. For example, this valve may be valve, diaphragm, hose and disk. In some ways, there are combined gas pressure regulators, the design of which uses seat and valve gates. The advantages of such devices, experts attribute the high tightness of the sealing system. For pipelines with high throughput, double-seat valves are used, which have a larger cross-sectional area than other regulators. At large stations, shutter valves have also become widespread. They operate in two stages and require the use of external energy sources, but they are reliable in controlling large volumes of gas flow.
Membranes are used as a sensitive organ. Some systems suggest 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 over wide ranges.
In accordance with technical standards, the installation of gas pressure regulators with shut-off and control elements must comply with the following requirements:
- The insensitive operating zone in its value should not exceed 2.5% relative to the maximum output pressure level.
- The proportionality zone in the case of balloon and combined regulators should also not be higher than 20% relative to the upper limit of the outlet pressure.
- Under conditions of sharp pressure drops in the circuit, the time of the technical transition of regulation should not be higher than 1 min.
Varieties of technical performance
Regulators for gaseous media are classified according to several technical and design features. In particular, the separation concerns the number of stages of reduction (reduction), the complexity of the mechanical design and the method of sampling the output pressure pulse.
As for the first sign, there are one- and two-stage models that differ in terms of flow characteristics. For example, a gas pressure regulator for a home with a flow rate of not more than 25 m 3 / h is more likely to have two stages of reduction. This work scheme is characterized by 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 be divided by a set of functions. In the first case, only the task of lowering the pressure is performed, and in the second, it also provides opportunities for noise reduction in the pipeline, valve protection and filtration. According to the pulse sampling system, gas pressure regulators can be divided with direct monitoring of output indicators, and devices with an external connection of sensitive elements. The main problem of using the second principle of sampling is the mandatory observance of the conditions for maintaining the flow stability on the circuit under investigation, otherwise the data will be incorrect.
Domestic and commercial gas pressure regulators
The structural, functional and ergonomic design of stop valves ultimately comes down to the requirements of a particular application. The emphasis is on the direct operating parameters, including output pressure, measuring ranges, flow rates, etc. For example, gas pressure regulators for household networks, as a rule, are characterized by low throughput and a modest range of settings. On the other hand, in such fittings an orientation is made 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 monitoring equipment. Devices of this type are distinguished by extended ranges of output and input pressure indicators, accuracy of settings, higher throughput and the presence of 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 enterprises due to their high reliability and maintainability.
Gas pressure regulator
The reducer is a self-contained device designed to control the pressure of the gas mixture at the outlet of any tank or pipeline. The main classification in this case involves the separation of regulatory nodes according to the principle of action. In particular, reverse and direct devices are distinguished. The reverse gear works to lower the pressure as the gas escapes. The design of such devices includes valves, chambers for the buffer content of the mixture, an adjusting screw and fittings. Direct action means that the regulator will work to increase the pressure when the gas is released.
Gearbox 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, piping networks and ramps (burners). In the case of cylinders, the type of gas will determine the method of connecting the device. Practically all models of reducers, except 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. External differences between the gearboxes are also provided - this can be color marking and 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, additional feedback is introduced, equalizing the pressure values. Moreover, it should be noted that the actual pressure in this case will differ from the normative value until the nominal load on the sensing element is restored.
The traditional design of a static gas pressure regulator provides for its own stabilizing device in the form of a spring - for comparison, in other versions a compensating load is used. During the working moment, the force developed by the spring must correspond to the degree of its deformation. The greatest degree of compression is obtained in situations when the membrane completely closes the control channel.
Astatic regulators under any load independently bring the pressure indicator to the desired value. The position of the regulatory body is also restored. However, as a rule, executive mechanics do not have a clear position - at different points in regulation, he can be in any position. Astatic control devices are more often used in networks with a high ability to self-level performance.
Gas Regulator
If a static pressure control system can be characterized as a model with rigid feedback, then isodromic devices interact with elastic elements of restoration of characteristics. Initially, when the deviation from the set value is fixed, the controller will take a position that corresponds to a value proportional to the rate of deviation from the norm. If the pressure does not normalize, the gas valve will shift towards compensation until the indicators return to normal.
From the point of view of the nature of the operation, the isodromic regulator can be called the 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 pre-isodromic reinforcement. This device is characterized in that the displacement rate of the actuator initially exceeds the rate of change of pressure. That is, the technique is ahead of the curve, saving time in restoring the parameter. At the same time, pre-regulators spend more energy from an external source.
Now we can proceed to consider specific models of gas pressure regulators. An overview of the best representatives of the segment is presented below.
Regulator Manufacturers
Devices for controlling and controlling the flows of gas mixtures in Russia are widely represented by both domestic and foreign manufacturers. In particular, the Gazapparat plant offers high-precision regulators of the RDNK series, which stably maintain the performance indicators 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 company, which is engaged in the development of control and measuring systems together with a large foreign company Emerson. These products are used in industry and in the domestic sphere. For example, gas services utilize 1098-EGR series systems in controlled farms, which are characterized by their fast response, accuracy of parameter settings and high performance. Basic modifications are quite suitable for gas fuel supply lines to network and local sampling points. GasTech enterprise comprehensively approaches the tasks of monitoring fuel and gas consumption. Specialists of the enterprise develop individual solutions for servicing gas installations of various types, regardless of their conjugation with other equipment.
Regulator operation
On the housing of the device provides several connecting holes of different diameters. The configuration of the connection system should be selected based on specific operating conditions. The most common are channel formats in the size range from 0.25 to 1 inch. The main fittings and adapters connected by means of rotating washers are suitable for such connections.
After making sure of the possibilities of introducing the regulator into a specific system, you can proceed to the direct installation. It is performed according to the following instructions:
- Connect the valve to the operating circuits by checking for gas. Close the valve completely and remove the plug to protect the shut-off valve, if any.
- Gently pull the cocking handle. The stroke should be small - about 10 mm.
- To cock the second stage, but gradually, so that there is no spasmodic gas supply. If possible, you can leave a small leak through the shut-off valve.
- The shut-off valve plug is put back.
- Slowly close the outlet valve, after eliminating process leaks.
During installation, you can perform basic settings of the gas pressure regulator according to several parameters: supply, shutoff 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 not more than 10% of those set in the documentation. To control the working pressure using a crosscut wrench. By turning the tip of the cap, 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 technological tasks, but also as a condition for ensuring safety. At large enterprises, stations and complexes with a hydraulic regime 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 valves in practice? Lowering and increasing pressure affects the condition of equipment and piping networks, which is especially important given the explosiveness of gas environments as such. Also, regulation is required as a condition for observing the established volume 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 the specified needs and operating conditions.
Of course, not only for the needs of industry are pressure regulators used in equipment serving gas mixtures. Both compact burners and boilers with boilers for this type of fuel also require the connection of controls. Another thing is that there are different schemes and configurations of gas flow control. Therefore, there are many varieties of gearboxes and regulators, the designs of which are focused on the needs of a particular user.