Design and operation principle gazaperedayuschih systems.

Flammable gases which will be discussed, almost all chemical compounds are hydrocarbons. The most natural gases are rasprastranenymi propane and methane.

We have with you a goal: to understand how the systems and mechanisms for pretormazhivaniyu, stopping and twisting the domestic gas meter class. It would therefore be considered only natural gas transmission system, low pressure (to reduce further as it is called LNG).

To adjust the supply of natural gas through LNG is mainly used plug valves. These valves are very reliable, since during operation, all parts are constantly lapped with each other, providing a permanent leak-tight unit, in general.

They consist of a body such as faucets, inside of which made a special cone-shaped nest, as well as openings for entry and exit of natural gas. In the cone-shaped nest of conical valve is installed. In a special flap done through hole, through which will pass gas. Conical valve tightly pressed against the conical wall socket with a special spring. Spring pressure on the valve is regulated by a special bolt pre - traffic jams. The spring and bolt - plug is also installed in the gas valve body nutria. The valve is operated by means of special pens that are either made one with a conical valve, or attached to it during the assembly of the gas valve.

Works like cock in the following way. When a hole in the cone-shaped flap coincides with the holes in the hull of the gas valve for the input and output of natural gas, obstacles to the passage of gas through the gas valve does not. In this case, the gas valve is open. If a hole in the cone-shaped flap does not coincide with the holes in the hull for the input and output of natural gas, the gas valve is closed. And if a hole does not coincide with some holes in the hull of the gas valve for inlet and outlet gas valve is partially open, and natural gas will pass through it in part. The direction of the holes relative to each other is regulated by turning of a cone-shaped flap in the cone-shaped nest.

To account for the use of natural gas consumers are mainly used gas meters of four types.

A. Membrane (diaphragm) gas meters. This type of gas meters are used to calculate natural gas use of small volume, no more than 12 cubic meters per hour. They are used mainly to calculate the natural gas of individuals in the private sector, as well as at enterprises and organizations where the use of natural gas is not a commercial necessity. The main advantage of membrane meter is simple to manufacture, low cost, relatively accurate count, even a small limit use of natural gas. The main disadvantage is that these counters are virtually unable to tolerate overloads, both temporary and permanent.

Counting mechanism in these counters mounted on the outside gas meter and a peripheral device. He is given by the measuring mechanism is mainly through the shaft. Shaft only a technical device that works both inside and outside gas meter. Seal between the shaft and the housing is made using special pre rezinoobraznyh glands.

Powered membrane counter as follows. Valve mechanism is designed so that its position limit any one of the bellows chamber should be filled with natural gas, and the other is emptied. Pre Fillable this camera bellows pressurized gas expands, resulting in a movement attached to it and the crank arm. After the lever is in a special way spool valve mechanism. Also, the lever is transmitted through another motion to the connecting rod opposite bellows camera causing it to shrink, resulting in the displacement of natural gas, which was filled earlier. When the expandable bellows chamber is filled to the limit, then the spool valve mechanism switches. In this case, bellows camera, which was filled, emptied starts, and the one which devastated, to be filled. Such a process will be repeated as long as the gas counter pressure will come new portions of natural gas.

Counting in the membrane gas meter is as follows. All bellows gas meter in the camera have the same volume. Counting mechanism is configured so that it counts how many times each camera came out of natural gas for a certain unit of time. Counting mechanism similar to estimates translates into a clear digital equivalent, and it is displayed on a special on the counting mechanism of the panel.

Two. The rotary gas meter. This type of meter is one of the first, which was used for calculation of consumption of natural gas appliances gas consumption. The main advantage of the rotary gas meter is a relatively high permeability, relatively small size and weight, "tolerance" to the overload, and these counters are pretty durable. The disadvantage of these counters is that manufacturing them requires very careful fitting of parts. It is also used relatively expensive materials. All this results in high cost of rotary meters.

Mainly used rotary meters, enterprises and organizations, where natural gas consumption does not exceed 200 cubic meters per hour (boilers, bakery, etc.). Sometimes they are used in the private sector for individuals.

The rotary gas meter consists of a case in which a special cavity in the shaft are two vosmeroobraznyh shaft. Shafts pre pre work synchronized with a gear transmission. To one of the oxen vosmeroobraznyh connected drive shaft counter mechanism. Counting mechanism, as well as at the counter of the membrane, is a peripheral device. Therefore, the shaft drive is running, as in the nutria, the gas meter, and from the outside. Seal between the shaft and the housing is made using special pre rezinoobraznyh glands.

Works rotating counter as follows. Shafts in the body cavity form a gas meter work pre pockets. This transformation is one of the pockets is always above the entrance of natural gas in case gas meter. Pre arrival of natural gas in the pocket to create a pressure that turns the vosmeroobraznye shafts. Eight shaped shaft, with the pocket, turning to the output of natural gas in the housing gas meter, produces natural gas. Natural gas comes out of the pocket in the output of the gas meter. Meanwhile, over the entrance of natural gas, gas meter, a new pocket is formed, which is also filled with natural gas, forming a pressure that is turning the vosmeroobrazny shaft. For a complete turnover of all the two rolls are formed vosmeroobraznyh four pockets, which have the same volume filled with natural gas.

Counting mechanism counts the number of revolutions made in a given period of time. Turnover multiplied by four and multiplied by the volume of one pocket. Indications are translated into the digital equivalent and displayed on a special panel in the counting mechanism.

Three. Turbine meter. These counters are mainly used in businesses and organizations, where natural gas consumption is very high. Also, like counters work on highways with a relatively high pressure. Such pressure natural gas pipeline in the private sector do not apply.

Turbine meters of construction is very complicated. The main parts of such a gas meter enclosure, within which is installed on the turbine wheel bearings.

Turbine meter runs as follows. Passing gas spins the turbine. With the rotation of the turbine shaft is transmitted to the ferrite magnet. Spinning, ferrite magnet consists of one turn every special switch (reed switch). Through the reed switch is omitted the electric current. Pre reed switch, an electric pulse which is fed to an electronic counting mechanism.

Counting mechanism on modern turbine meters is a mini computer system. This system not only counts the pulses and converts them to digital equivalent, but also ensure the proper operation of the gas meter, and the signals are not authorized intervention in the operation of the unit. In the most advanced mechanisms for counting turbine gas meters are equipped with a modem, through which passed all the evidence straight to the servers gas inspection services.

4. Vortex Flowmeter. Practically the most sophisticated device of the mechanisms for metering of natural gas. Describe the unit vortex flowmeter does not make sense, since it is practically applied to very large enterprises and organizations with a large quantity of natural gas consumption. They work on the basis depending on the flow rate of pressure fluctuations arising in flow in the vortex of the jet or fluctuations, or after some form of barriers installed in the pipeline, or a special twist thread.

Counting mechanisms in such devices as well as turbine meters are on a mini computer system, some of which are equipped with modems.

There are also liquid-gas meters. Some of the most accurate gas meters. But from - the complexity of design and complexity of such a service counter in the main exchange in labaratornyh conditions. They work on the principle of pushing the speed of certain gaseous substances, in certain portions of certain liquid substances (mostly destilirovanoy water). Portions of ejection of gas from the liquid substance specified lapataobraznym shaft of the special form.