Device
The acetylene gas cylinder is made from seamless pipes in accordance with GOST 949-73 . Wall thickness 7 – 8 mm. The ends of the container are spherical. The top part has a hole into which the valve is screwed. A cylindrical shoe is placed on the lower part, giving the container stability.
The neck in acetylene cylinders is wider than in others where gas is stored. Through it, the container is filled with a porous mass: cast porous filler, activated birch carbon and basalt fiberglass. The loose substance absorbs acetone well and promotes uniform dissolution of acetylene in it.
Foreman of the acetylene cylinder filling section of the SpetsBallonMash plant Kurnikov A.I.: “The Americans fill the inside of an acetylene cylinder with asbestos cord. At the end of the last century, the Russian Federation abandoned such material as carcinogenic. Small particles of asbestos evaporate along with argon. In Russia, they switched to natural materials that absorb acetone: silk, leather, mineral wool, sawdust. Currently, some manufacturers use asbestos in small quantities as an additive to quartz sand and calcium hydroxide. In Germany, charcoal is mixed with magnesium carbonate and kieselguhr. When purchasing a cylinder, you should pay attention to its filling. Asbestos causes lung cancer."
Storage of acetylene - general provisions.
Due to the fact that acetylene is explosive not only when mixed with air or oxygen, but also in a pure state, there is a possibility of the cylinder exploding if a backfire occurs or if it is accidentally heated by a burner. Acetylene is stored in transport and small-capacity cylinders of a special design.
To prevent the spread of a blast wave in an acetylene cylinder, it is filled with a special cast porous mass, which most often is activated carbon, pumice, or asbestos fiber. Acetylene pumped under pressure fills all the pores of the material; to increase the gas volume, the filler is impregnated with acetone, which increases the absorption of the material. For example, up to 13 liters of acetone are poured into a transport acetylene cylinder, one liter of which can hold up to 23 liters of gas. In total, the transport cylinder can hold up to 6 kilograms of acetylene. This design of the cylinder allows the filler to dampen the resulting shock waves from an acetylene explosion, which significantly increases work safety.
Cylinders for acetylene storage are painted with white enamel, the inscription “Acetylene” is applied to it, under it are the letters “LM”, which indicates that the cylinder is filled with a cast porous mass. These inscriptions must be red.
Refueling
Acetylene is produced by combining water and carbide . Acetylene cylinders are filled through the neck, determining its quantity by weight. Standard full cylinder 65 kg, empty 53 – 58 kg. The weight of the container with filler is indicated at the marking on the neck and is determined by weighing.
The acetone partially evaporates along with the gas. At each refill, add 130 - 150 ml.
If you fill a 5 liter container from a 40 liter cylinder, the gas in it will run out very quickly. In order for acetylene to dissolve in acetone, high pressure must be created. When pumping at home, it is impossible to create it .
Cylinder explosion
The main disadvantage of acetylene is its explosiveness. Gas can detonate for many reasons:
- achieving a critical mass of gas;
- high pressure;
- residue in the flammable gas cylinder;
- contact with lubricant or calcium carbide;
- electrification of the neck by the gas itself, passing at high speed;
- heat;
- leakage and air connection;
- impacts on the weakened walls of the container.
The gas becomes explosive if it is collected in large volumes and when the acetylene pressure in the cylinder exceeds 2 kg/cm2. To reduce the risk of spontaneous explosion, a special porous mass is placed inside the gas container. It divides all the gas into small particles, allowing it to move freely. Pure acetylene can be pumped with a maximum pressure of 25 kg/cm2.
How does an acetylene cylinder work?
Powering gas welding and cutting stations with acetylene from acetylene generators is associated with a number of inconveniences, so powering stations directly from acetylene cylinders is now widespread. They have the same dimensions as oxygen ones (Fig. 17, b). An acetylene cylinder is filled with a porous mass of activated charcoal (290 - 320 g per 1 dm3 of cylinder capacity) or a mixture of coal, pumice and infusorial earth. The mass in the cylinder is impregnated with acetone (225-300 g per 1 dm3 of cylinder capacity), in which acetylene dissolves well. Acetylene, dissolving in acetone and being in the vapor of the porous mass, becomes explosion-proof, and it can be stored in a cylinder under a pressure of 2.5-3 MPa. The porous mass must be soft and have maximum porosity, behave inertly towards the metal of the cylinder, acetylene and acetone, and not produce sediment during operation.
Rice. 17. Oxygen (a) and
acetylene (b) cylinders
Acetone (CH3COCH3) is one of the best acetylene solvents; it impregnates the porous mass and dissolves it when filling cylinders with acetylene. Acetylene delivered to consumers in cylinders is called dissolved acetylene.
The nominal pressure of acetylene in the cylinder is 1.9 MPa. The pressure of acetylene in a fully filled cylinder changes with temperature:
Temperature,
0 C -5 0 5 10 15 20 25 30 35 40
Pressure, MPa 1.34 1.4 1.5 1.65 1.8 1.9 2.15 2.35 2.6 3
The pressure of filled cylinders should not exceed 1.9 MPa at 20 0C.
When the valve of the cylinder is opened, acetylene is released from the acetone and enters in the form of a gas through the reducer and hose into the burner or cutter. Acetone remains in the pores of the porous mass and dissolves new portions of acetylene during subsequent fillings of the cylinder with gas. To reduce acetone losses during operation, it is necessary to keep acetylene cylinders in a vertical position. At normal atmospheric pressure and a temperature of 20 0C, 28 kg (l) of acetylene are dissolved in 1 kg (l) of acetone. The solubility of acetylene in acetone increases (approximately directly proportional) with increasing pressure and decreases with decreasing temperature.
To fully utilize the cylinder capacity, it is recommended to store empty acetylene cylinders in a horizontal position, which promotes uniform distribution of acetone throughout the entire volume, and with the valves tightly closed. When acetylene is removed from the cylinder, it carries away some of the acetone in the form of vapor. This reduces the amount of acetylene in the cylinder during subsequent fillings. To reduce the loss of acetone from the cylinder, acetylene must be withdrawn at a rate of no more than 1700 dm3/h.
To determine the amount of acetylene, the cylinder is weighed before and after filling with gas and the amount of acetylene in the cylinder in kilograms is determined from the difference.
EXAMPLE
The mass of the cylinder with acetylene is 89 kg, empty - 83 kg, therefore, the amount of acetylene in the cylinder is equal to: by weight 89-83 = 6 kg, by volume 6: 1.09 = 5.5 m3 (1.09 kg/m3 - density acetylene at atmospheric pressure and temperature 20 ° C).
The mass of an empty acetylene cylinder consists of the mass of the cylinder itself, the porous mass and acetone. When taking acetylene from a cylinder, 30-40 g of acetone per 1 m3 of acetylene is consumed along with the gas. When removing acetylene from a cylinder, it is necessary to ensure that the residual pressure in the cylinder is at least 0.05-0.1 MPa.
The use of acetylene cylinders instead of acetylene generators provides a number of advantages: compactness and ease of maintenance of the welding installation, safety and improved working conditions, increased productivity of gas welders. In addition, dissolved acetylene contains fewer impurities than acetylene obtained from acetylene generators.
The reasons for the explosion of acetylene cylinders can be sharp shocks and impacts, strong heating (over 40 ° C).
How much is 40l?
The volume of acetylene in a fully filled gas container is calculated using a simple formula:
40 × 15 × 9.2 = 5520 l;
Where: 40 l – cylinder volume;
15 kg/cm2 – pressure;
9.2 gas solubility coefficient in acetone;
5520 l = 5.5 m3 amount of acetylene.
This formula calculates the amount of acetylene that can be filled into any size cylinder. In the formula, only 40 – the number of the container’s volume – changes to 5, 10 and others .
Application of acetylene
As mentioned earlier, such a compound has increased reactivity. Accordingly, it is used to synthesize various materials. This can be rubber, ethyl alcohol, carbon black, etc. Acetylene is also used in the production of explosives, rocket engines and lighting equipment.
We have already mentioned the fact that when a substance is burned, a significant amount of heat is generated. It is for this reason that acetylene is often used in the cutting and welding process.
various metals. The main competitor of acetylene in this area is propane-butane. The latter type of gas is cheaper, but it produces a low combustion temperature.
Cylinders or generators can be used to supply gas during the welding process. The first option is considered more preferable. Standard cylinders designed for 40 liters are recognized as the optimal product. They are painted white. At the same time, “Acetylene” is written on the surface in red.
It is worth noting that only dissolved and gaseous technical acetylene is suitable for gas-flame processing. itself is filled inside with a special porous mass
, pre-impregnated with acetone. This layer performs 2 important functions.
- Increased safety during work. Thus, the likelihood of fire and explosion spreading over a large area is reduced.
- Increasing the amount of acetylene and accelerating the process of its release. This is possible due to the provision of a significant contact surface between the gas and acetone.
The porous mass is usually activated carbon and fibrous asbestos. The use of pumice is also allowed.
What's the pressure?
According to GOST, pressure is determined at a temperature of + 20⁰C. Limit value 19 kgf/cm2. Typically, acetylene in cylinders has 14 - 16 kgf/cm2.
Gas pressure depends on temperature changes. For example, 19 kgf/cm2 at 20⁰ when cooled to -4, a total of 13.4 kgf/cm2, at 35⁰ a critical value of 26 kgf/cm2 is reached. Therefore, a pressure reserve is created in case of heating.
You can determine the amount of gas filled by a simple calculation. You need to subtract the weight of the empty cylinder from the weight after refueling and multiply by 1.09 - that’s how much a liter of gas weighs.
Cylinder for dissolved acetylene
The cylinder for dissolved acetylene contains a steel cylindrical body 1, tapering in the upper spherical part towards the neck (not indicated), a steel shut-off valve 2 on the neck, as well as a porous mass 6 packed in the body 1 to form a volume above it for a gas cushion 5, which is dried active crushed charcoal, compacted to a density of 300÷370 grams per liter of capacity of housing 1, into which technical acetone is introduced to impregnate the porous mass at the rate of 275±10 grams per 1 liter of capacity of housing 1 cylinder with the formation of a gas cushion, the volume of which is 16- 20% of the body volume of 1 cylinder. Moreover, with an increased density of coal, the residual moisture content in the coal packed in the body of 1 cylinder does not exceed 1%, which has a positive effect on the gas collection capacity of the cylinder. The porosity of coal packed in the body of 1 cylinder is 76÷80%. The strength of coal packed in the body of 1 cylinder is at least 60%. The mass fraction of ash in coal packed in the body of 1 cylinder is no more than 7%, the adsorption activity for iodine is no less than 60%. The particle size of coal packed in the body of 1 cylinder is 1.0-3.6 mm. The cylinder has a gas absorption capacity of at least 125 grams of acetylene per 1 liter of body capacity of 1 cylinder. The cylinder is equipped with a removable safety cap 4 and a neck ring 3 made of carbon steel, made with internal and external threads, respectively, for installation as an assembly on the neck of the housing 1. As a result, increased gas collection of the cylinder is ensured, reducing losses and eliminating the possibility of excessive pressure increase in the housing cylinder, as well as the ability to increase the number of permissible charging/discharging cycles of the cylinder, i.e. its service life.
The utility model relates to the gas industry, namely to vessels for storing or storing gases in a compressed state. Cylinders filled with a porous mass and an acetylene solvent - acetone, are intended for storing and transporting dissolved acetylene obtained from calcium carbide and pyrolysis acetylene.
There are various designs of cylinders intended for storing and transporting gases, including flammable ones. These include metal vessels of various capacities designed for high pressure. They consist of a cylindrical shell, upper and lower bottoms and a pipe with a valve. For gases prone to explosive disintegration, cylinders are filled with a porous nozzle. Cylinders with porous nozzles are used for the following gases: acetylene, methyl acetylene, propadiene and propylene (Dolin P.A. “Safety Handbook.” M. Energoizdat, 1982).
A known cylinder for dissolved acetylene. The cylinder consists of a cylindrical body, two bottoms, a support shoe and a valve. Activated carbon is placed inside the cylinder as a porous flame-extinguishing nozzle. To dissolve acetylene, acetone is pumped into the cylinder (Strizhevsky I.I. “Safety precautions in the production of acetylene.” M. Khimiya, 1978).
The disadvantage of such a cylinder is the insufficient gas collection capacity of the acetylene cylinder, as well as the possibility of complete burnout of acetylene with simultaneous destruction of the porous structure of activated carbon during the so-called reverse flame strike, that is, when the flame enters the cylinder from the side of the acetylene consumer or when it is filled at an acetylene station.
A cylinder for dissolved flammable gas is known, containing a cylindrical body with a neck, filled with a porous mass impregnated with acetone, and the cylinder has a safety nozzle in the upper volume adjacent to the neck, characterized in that the safety nozzle is made in the form of a hydrophilic fusible substance placed between two meshes. Phosphorus pentoxide (RU 2082913) was used as a hydrophilic fusible substance
The disadvantage of this cylinder is its high cost, large losses of acetylene and insufficient gas collection, insufficient number of charge/discharge cycles of the cylinder.
A known cylinder for dissolved acetylene contains a steel cylindrical body tapering towards the neck, a steel shut-off valve on the neck, and also a porous mass stuffed in the body up to the neck, which is dried active crushed wood coal with a density of 240 grams per liter, into which an impregnating porous mass is introduced technical acetone (https://electrowelder.ru/index.php/19-2/gazosvarschik/105-manometers.html, prototype).
The disadvantage of this cylinder is insufficient gas collection, as well as the possibility of increasing pressure in the body and spilling out crushed coal, and an insufficient number of charging/discharging cycles of the cylinder.
The technical task of the utility model is to create an effective cylinder for dissolved acetylene and expand the arsenal of cylinders for dissolved acetylene.
The technical result that provides a solution to the problem is to increase gas collection (up to at least 125 grams of acetylene per 1 liter of cylinder body capacity), ensured due to the increased density of the porous mass, and reduce losses (acetone loss when discharging the cylinder does not exceed 50 ml/m3 acetylene), and eliminating the possibility of an excessive increase in pressure in the cylinder body due to the fact that part of the volume of the cylinder body (16-20%) is not filled with acetone. The increased density of the porous mass allows you to increase the number of permissible charging/discharging cycles of the cylinder.
The essence of the utility model is that a cylinder for dissolved acetylene contains a steel cylindrical body tapering towards the neck, a steel shut-off valve on the neck, as well as a porous mass packed into the body to form a volume above it for a gas cushion, which is dried active crushed charcoal , compacted to a density of 300÷370 grams per liter of body capacity, into which acetone is introduced to impregnate the porous mass at the rate of 275±10 grams per 1 liter of cylinder body capacity to form a gas cushion, the volume of which is 16-20% of the volume of the cylinder body.
Preferably, the residual moisture content in the coal packed in the cylinder body does not exceed 1%, the porosity of the coal stuffed in the cylinder body is 76÷80%, the strength of the coal stuffed in the cylinder body is at least 60%, the mass fraction of ash in the coal , stuffed in the cylinder body is no more than 7%, the size of the coal particles stuffed in the cylinder body is 1.0-3.6 mm.
In this case, the cylinder is made with a gas collection capacity of at least 125 grams of acetylene per 1 liter of the capacity of the cylinder body, and is equipped with a removable safety cap and a neck ring made of carbon steel, made with internal and external threads, respectively, for installation as an assembly on the neck, the body is equipped with a made of carbon steel with a removable support shoe and made of carbon steel with strength designed for a working pressure of 9.8 MPa (100 kgf/cm2).
The drawing of Fig.1 shows a cylinder for dissolved acetylene with a local section, in Fig.2 - a support shoe, in Fig.3 - a top view of Fig.2, in Fig.4 - a safety cap, in Fig.5 - a top view of Fig.4, Fig.6 - neck ring.
The drawings show cylinder body 1, shut-off valve 2, neck ring 3, safety cap 4, gas cushion 5, porous mass 6 with acetone, support shoe 7.
The cylinder for dissolved acetylene contains a steel cylindrical body 1, tapering in the upper spherical part towards the neck (not indicated), a steel shut-off valve 2 on the neck, as well as a porous mass 6 packed in the body 1 to form a volume above it for a gas cushion 5, which is dried active crushed wood coal, forcibly compacted to a density of 300÷370 grams per liter of housing capacity 1, into which technical acetone is introduced to impregnate the porous mass at the rate of 275±10 grams per 1 liter of housing capacity 1 cylinder with the formation of 1 cylinder in the upper part of housing 1 under the neck gas cushion, the volume of which is 16-20% of the volume of the body of 1 cylinder.
At the same time, the residual moisture content in the coal packed in the body of 1 cylinder does not exceed 1%, which has a positive effect on the gas collection capacity of the cylinder, especially with the specified increased density of the coal.
The porosity of coal packed in the body of 1 cylinder is 76÷80%.
The strength of coal packed in the body of 1 cylinder is at least 60%.
The mass fraction of ash in coal packed in the body of 1 cylinder is no more than 7%, the adsorption activity for iodine is no less than 60%.
The particle size of coal packed in the body of 1 cylinder is 1.0-3.6 mm.
Active crushed charcoal is a flammable substance with a smoldering temperature in the layer of at least 240°C.
The cylinder has a gas absorption capacity of at least 125 grams of acetylene per 1 liter of body capacity of 1 cylinder.
The cylinder is equipped with a removable safety cap 4 made of carbon steel and a neck ring 3 made with internal and external threads, respectively, for installation as an assembly on the neck of the body 1.
Housing 1 is equipped with a removable support shoe 7 made of carbon steel.
Housing 1 is made of carbon steel with strength designed for a working pressure of 9.8 MPa (100 kgf/cm2) and painted with white enamel.
Neck ring 3 made of carbon steel of ordinary quality is installed on the body of 1 cylinder by crimping. A safety cap 4 is screwed onto ring 3. Gas cushion 5 is the space in the upper spherical part of the body 1 of the cylinder (between the porous mass 6 with acetone and valve 2), filled with acetylene. The support shoe 7 made of carbon steel of ordinary quality can be installed on the body 1 of the cylinder by crimping or screwed onto the thread (depending on the design of the cylinder).
The manufacture and operation of cylinders must be carried out in accordance with the requirements of the “Rules for the design and safe operation of pressure vessels” (PB 03-576-03). The cylinder with a screwed-in valve must be sealed at a pressure of 3.5 MPa (35 kgf/cm2. A cylinder manufactured for export for delivery to countries with temperate or tropical climates must comply with the “Conditions for the supply of goods for export” and the requirements of GOST 15151-69 .
The main parameters and dimensions of the cylinder body, its design, mechanical properties of the material, as well as coloring and markings must comply with GOST 949-73, for cylinders made of carbon steel of ordinary precision
The cylinder for dissolved acetylene is operated as follows.
Acetone is poured into the body 1 of the cylinder, impregnating the porous mass 6. The amount of acetone is taken taking into account the possibility of increasing its volume when acetylene is dissolved. Porous mass 6 performs the following functions:
— increases safety when working with a cylinder — due to the porous mass, the total volume of acetylene is divided into separate cells; thus, the probability of the spread of the general front of combustion and explosion is significantly reduced, and increasing the density of coal to a density of 300÷370 grams per liter of capacity significantly increases the number of these cells;
- allows you to increase the amount of acetylene in the cylinder, speed up the process of its dissolution when filling the cylinder and releasing it when taking gas - since when using a porous mass impregnated with acetone, a large surface area of mutual contact between gas and acetone is provided, and the density of coal is increased to a density of 300÷370 grams per liter of capacity significantly increases such area.
Gas cushion 5 is a volume unfilled with coal and acetone (16-20%) in the upper part of the cylinder body, filled with compressed acetylene gas saturated with acetone vapor.
To charge (fill) acetylene is pumped into the cylinder and dissolved in acetone under a pressure of 15-18 atm. Cylinders are filled at special filling stations using special acetylene piston compressors. Acetylene is supplied to the cylinders and dissolved over several hours until the pressure in the cylinder reaches 15-18 atm at 15°C. A normal 40-liter acetylene cylinder holds about 6 m3 of acetylene.
Before filling the cylinders, acetylene is thoroughly cleaned and dried, passing through dryers with chemical moisture absorbers. Drying is necessary, since water entering acetone greatly reduces the solubility of acetylene.
Acetylene is a gas produced from calcium carbide. Acetylene (C2H3) is a chemical gaseous compound of carbon with hydrogen, colorless, with a weak ethereal odor and a sweetish taste. Acetylene is the only gas widely used in industry and is one of the few compounds whose combustion and explosion are possible in the absence of oxygen or other oxidizing agents. Acetylene cannot be filled into cylinders under high pressure, as is practiced for other gases, due to the possibility of explosive self-disintegration.
Acetylene dissolves well in acetone: at normal temperature and pressure. Dissolving acetylene in acetone allows large quantities of acetylene to be contained in a small volume, and in this respect is equivalent to compressing the gas to very high pressures. A solution of acetylene in acetone is significantly less explosive than acetylene gas. The safety of dissolved acetylene is further enhanced if the solution impregnates a solid porous mass with microscopic pore sizes. In this form, dissolved acetylene is practically safe from explosion.
Safety cap 4 serves to protect valve 2 from mechanical damage and contamination. Shoe 7 ensures the stability of the cylinder during operation and transportation.
Distribution of acetylene from the cylinder to consumers is carried out by opening valve 2. Opening and closing of valve 2 is carried out with a socket wrench placed on the square head. Valve 2 does not have a fitting. The gas in the gas cushion reaches the consumer through a valve and reducer (not shown).
The gearbox is connected using a special clamp with a clamping bolt. When valve 2 of the acetylene cylinder is opened, the pressure in it drops, acetylene dissolved in acetone begins to be released in gaseous form and is directed through valve 2 and the reducer to the point of consumption. Some acetone is carried away with acetylene; To avoid excessive entrainment, you should not take more than 2 m3/hour of acetylene from the cylinder and stop taking gas when the pressure in the cylinder drops to 2 ati. Before each filling of the cylinder with acetylene, acetone is added to the cylinder.
The release of heat during the combustion of acetylene is due to the following processes:
acetylene decomposition: C2H2=2C+H2
carbon combustion: 2C+O2=2CO, 2CO+O2=2CO2
hydrogen combustion: H2+1/2O 2=H2O
The maximum permissible loss of acetylene in a cylinder when filling is 0.00061 m3/h, when discharging - 0.00061 m3/h.
Increased gas collection capacity of the cylinder (at least 125 grams of acetylene per 1 liter of cylinder body capacity) is ensured due to the increased density of the porous mass, amounting to 300÷370 grams per liter of capacity and the introduction of acetone at the rate of 275±10 grams per 1 liter of cylinder body capacity, reducing losses (carryover of acetone when discharging a cylinder does not exceed 50 ml/m3 of acetylene), and eliminating the possibility of an excessive increase in pressure in the cylinder body due to the fact that part of the volume of the cylinder body (16-20%) is not filled with acetone. The increased density of the porous mass allows you to increase the number of permissible charging/discharging cycles of the cylinder, i.e. its service life.
1. A cylinder for dissolved acetylene containing a steel cylindrical body tapering towards the neck, a steel shut-off valve on the neck, as well as a porous mass packed into the body to form a volume above it for a gas cushion, which is dried active crushed charcoal, compacted to a density of 300 ÷370 g/l capacity of the body, into which acetone is introduced to impregnate the porous mass at the rate of 275±10 g/l of the capacity of the cylinder body to form a gas cushion, the volume of which is 16-20% of the volume of the cylinder body.
2. The cylinder according to claim 1, characterized in that the residual moisture content in the coal packed in the cylinder body does not exceed 1%.
3. The cylinder according to claim 2, characterized in that the porosity of the coal packed in the cylinder body is 76÷80%.
4. The cylinder according to claim 3, characterized in that the strength of the coal stuffed in the cylinder body is at least 60%.
5. The cylinder according to claim 4, characterized in that the mass fraction of ash in the coal packed in the cylinder body is no more than 7%.
6. The cylinder according to claim 5, characterized in that the size of the coal particles packed in the cylinder body is 1.0-3.6 mm.
7. The cylinder according to claim 6, characterized in that it is made with a gas collection capacity of at least 125 g of acetylene per 1 liter of cylinder body capacity.
8. A cylinder according to any one of claims 1-7, characterized in that it is equipped with a removable safety cap and a neck ring made of carbon steel, made with internal and external threads, respectively, for installation as an assembly on the neck.
9. A cylinder according to any one of claims 1-7, characterized in that the body is equipped with a removable support shoe made of carbon steel.
10. A cylinder according to any one of claims 1-7, characterized in that the body is made of carbon steel with a strength designed for a working pressure of 9.8 MPa (100 kgf/cm2).
Cylinder color
Externally, unpainted acetylene containers differ only in the width of the neck. They have a diameter of 210 mm and a standard support shoe. After painting with enamel in preparation for work, the acetylene cylinder is white . In the upper quarter of the cylindrical part the word “Acetylene” is written in red. Letters 60 - 100 mm high should occupy at least half the circumference of the container.
There is a marking on the cone near the neck. It includes:
- manufacturer's trademark;
- factory mark;
- individual number;
- brand of the organization that carried out the technical examination;
- date of manufacture;
- year of next maintenance;
- operating pressure;
- capacity in liters;
- weight in kg.
The marking is stamped onto clean metal, outlined around the perimeter with red paint and coated with varnish to protect the surface from corrosion..
Valve
The locking device is made of steel. With prolonged contact with copper and bronze, a chemical reaction occurs and acetylenide is formed - a combination of copper with carbon and the release of hydrogen. Copper acetylene can cause an explosion .
The valve is connected to the neck with a clamp. The thread on the fitting is left - counterclockwise.
There are no taps usual for other gas tanks. The valve is opened with a special socket wrench by rotating a square spindle located in an axis along the entire length of the body. The clamp pressure screw has a small hole on one side for the outlet fitting.
Valve device
The cast body has a through hole of variable cross-section along the axis. It contains a rod, the upper part of which is rotated with a key. At the bottom it has an ebonite seal that blocks the gas outlet.
When the spindle rotates, the hole at the bottom opens. The gas rises and exits from the side through an attached fitting. The upward exit along the spindle is blocked by leather and steel rings, which are pressed with a steel nut.
The housing fitting is sealed with a leather gasket, which is located in the recess around the hole and serves as a stop for the end of the screwed fitting.
Cylinder valves
Arrangement of cylinder shut-off valves
A valve is a shut-off device used to fill gas cylinders, supply gas, for example, to a burner or cutter, and allow gases to be stored in the cylinder. Technical data of some cylinder valves currently produced are given in the table:
The operating principle of cylinder valves is the same, but they differ in the material from which they are made, the connecting thread and the method of sealing.
Valves for oxygen cylinders are made of brass. It is impossible to use steel for the manufacture of valve parts, since it is highly corrosive in a compressed oxygen environment. In an oxygen valve, due to accidental ingress of oil or ignition from friction of the fiber seal gasket, steel parts may catch fire, since steel can burn in a compressed oxygen environment. Brass does not burn in oxygen and is safe to use in oxygen cylinder valves. Handwheels and plugs can be made of steel, aluminum alloys and plastics.
* GOST 2.601-95. Unified system of design documentation. Operational documents.
2 GOST 5539-73. Lead litharge. Technical conditions.
3 GOST 19151-73. Lead minium. Technical conditions.
4 GOST 7931-76. Natural drying oil. Technical conditions.
To prevent fires when filling and handling oxygen cylinders among consumers, it is necessary to exclude the use of parts (seals, gaskets, rods, etc.) made from materials not approved for use in oxygen environments when repairing fittings. The material of the sealing gaskets is selected in accordance with GOST 12.2.052-81. The oxygen valve consists of a body and a shank with a conical thread to secure the valve in the neck of the cylinder. The valve is connected to the BKO reducer through the side fitting. The housing seat hole is closed by a valve equipped with a sealing insert. The tightness of the valve at the point where the spindle passes through the stuffing box nut is ensured by pressing the spindle seat against the gasket by spring force. In addition, compressed oxygen flowing from the cylinder into the valve cavity will additionally press the spindle seat against the gasket, as a result of which the connection will become even more airtight. The rotation of the handwheel is transmitted to the valve through a coupling that fits onto the square shanks of the spindle and valve.
In a diaphragm valve, the membrane is made of phosphor bronze or stainless steel with a thickness of 0.1-0.15 mm. The valve is closed by valve 2
In order to open the valve for oxygen to exit the cylinder, you need to turn the handwheel. The valve opens by turning the handwheel counterclockwise and closes by turning it clockwise. All parts of oxygen valves must be thoroughly degreased and protected from contamination during operation.
To seal the threaded connection of the valve in the neck of the cylinder, use FUM tape or liquid glass (a mixture composed of 50% liquid glass according to GOST 13078-81′ and 50% chalk according to GOST 8253-792).
During operation, it is necessary to periodically inspect the valve, paying special attention to the tightness of its connections, the mechanical safety of parts, as well as the quality of the fitting thread, the wear of which causes the union nut of the gearbox to break.
It is strictly forbidden to open the valve by tapping with foreign objects, to bring an open flame to it, or to handle it with dirty, oily hands.
Valves for oxygen cylinders can also be used for nitrogen, carbon dioxide, compressed air and other non-aggressive gases.
The valve for hydrogen cylinders is designed for a working pressure of 19.6 MPa (200 kgf/cm2). Structurally, it is similar to the valve of an oxygen cylinder and differs only in the presence of a left-hand thread on the connecting fitting instead of a right-hand thread on a VK-type valve. The BB-88 valve is commercially produced, having a connecting fitting with a left-hand thread with a diameter of 21.8 mm, 14 threads per 1″ (thread profile according to GOST 6357-81).
' GOST 13078-81. Liquid sodium glass. Technical conditions. 2 GOST 8253-79. Chemically precipitated chalk. Technical conditions.
Valves of acetylene cylinders are usually made of steel. It is prohibited to use copper and its alloys with a copper content of more than 65% for parts of these valves, since acetylene with copper forms an explosive - acetylene copper.
The reducer is connected to the acetylene cylinder valve using a special steel clamp equipped with a tension screw. The valve does not have a handwheel, since the latter would interfere with putting on the connecting clamp with a tension screw. The valve is opened and closed using a special socket wrench placed on the square of the spindle. By rotating counterclockwise, the spindle is unscrewed, opening the acetylene outlet into the gas cavity of the valve, and from there through the outlet channel of the fitting into the gearbox. When the spindle rotates clockwise, it lowers and covers the body seat with an ebonite seal. The lower part of the spindle has an ebonite insert and serves as a valve. A set of leather rings is used to seal the oil seal.
The seal between the spindle and the housing is achieved using leather gland gaskets resting on the gland ring and compressed by a gland nut through a washer. Since the seal is made of hard rubber, closing the valve requires less force than closing valves with metal seals.
A felt filter and steel mesh with a mesh size of 1.4 mm are placed in the tail part of the valve, which is screwed into the cylinder. To prevent falling out of the housing, the felt filter and mesh are secured with a steel wire ring. A filter with mesh serves to protect against porous particles that can get from the acetylene cylinder into the valve seal and the reducer attached to the valve.
As noted above, the valve of an acetylene cylinder has a thread different from other types of valves, which precludes the possibility of installing it on other cylinders. The neck thread of acetylene cylinders has an outer diameter in the plane of the end of 30.3 mm', and for all other cylinders 27.8 mm. The valve for acetylene cylinders is designed for a working pressure of 3.5 MPa (35 kgf/cm2).
A valve for propane-butane , as a rule, has a brass body (although it is possible to use steel for the manufacture of the valve), a valve, a spindle, connected by an elastic rubber cuff that ensures the tightness of the stuffing box nut.
The valve must comply with GOST 21804 and is designed for gas operating pressure up to 1.6 MPa (16 kgf/cm2). Valves for propane-butane have connecting fittings with the same threads as the valve type BB-88. Valve VB-2 can be used as a shut-off device for propane-butane cylinders. The maximum operating pressure of the valve is 40 kgf/cm2.
Storage
Oxygen and acetylene cylinders are stored separately from each other. The conditions are the same:
- containers must stand vertically;
- place the cylinders in special stands and fix them;
- the room temperature should not exceed 25⁰C;
- should not be placed near heating devices or open flames;
- batches at the warehouse should not exceed 20 pieces.
Valves on containers with argon in the non-working position must be closed with special caps. As for acetylene cylinders, they are also sorted by volume.
You cannot keep a container nearby that is larger or smaller than the main group.
Equipment / For the garage: furniture, fixtures, etc. / How to safely cut an acetylene cylinder
For one of our future projects, we have had an acetylene cylinder lying around for a very long time and waiting its turn. Somehow there was no use for it, and accordingly we didn’t even think about how to cut it safely. And now, his time has come. Once the cylinder expired and was taken out of service, more than twenty years have passed. Naturally, after that it was already stored as needed, and basically it was on the street, with all the rusty consequences. It was completely impossible to unscrew the valve of the cylinder and check whether there was gas in it. No matter how hard they tried. But under no circumstances should you cut like that; something had to be done. Even if the cylinder is empty, there is still gas left in there. The container for storing and transporting acetylene always includes a porous filler in which the gas is retained. And if you cut an unprepared cylinder, it will completely fail! So what to do? You can’t knock, heat or saw! You can try carefully drilling two holes at the top and bottom of the cylinder and pumping water into it under pressure. We will drill the cylinder with a drill with a diameter of six millimeters at low speeds and in a stream of water. Place the cylinder on its side and get started.
For this work, you need to use exclusively new or freshly sharpened drills. Each hole must be drilled with a new drill. This is necessary in order to minimize the number of revolutions of the cutting edges on a dangerous object and heat the cutting area as little as possible. After the holes are drilled, install the cylinder in a vertical position.
Next, install a fitting with a hose in the lower hole and supply water. This way the balloon is filled with water. It took about an hour and a half. After water begins to flow out of the upper hole, we do not interrupt the process, but continue to spill the bottle, filling absolutely all the pores. We poured water into the bottle for another half hour. Next, we plug the holes with wooden plugs and again lay the cylinder on its side.
Now you can safely cut it. The cutting process took us no more than fifteen minutes.
Inside there really is finely dispersed, densely compacted birch charcoal.
It is really compacted very tightly, it is not so easy to unscrew it even with a screwdriver.
The process of emptying the container was difficult. I had to constantly pick it out and hit the walls of the cylinder with a small sledgehammer so that the coal would fall off.
After a while we got used to it, and the process went much faster.
The portion of the cylinder that is required for the new project has been released. There was a lot of coal.
Coal looks like small crystals.
We will not release the second part of the cylinder yet.
