LPG Natural Gas Sampling Cylinder
Main features of gas sampling cylinder:
1. One-time spinning forming technology is adopted, no welding, 316L stainless steel material; corrosion resistance and high temperature resistance are more superior.
2. The wall thickness of the sampling cylinder is uniform, the inner surface is pickled and passivated, and the smooth inner wall is easy to clean.
3. The cold-formed NPT internal thread has greater strength.
4. The stainless steel handle is installed, which can easily carry the sampling cylinder, which is strong and durable and will not be damaged.
5. The 2-end needle valve structure has overpressure protection function, and the valve is equipped with an explosion-proof pressure relief device. .
6. A pressure gauge can be installed to display the pressure in the bottle.
7 More than ten accessories are available for purchase to meet the sampling needs of different environments, different media and other complex factors.
8 According to user needs, PTFE can be sprayed on the inner surface of the bottle to obtain a smooth anti-corrosion inner coating to effectively prevent the trace elements of the gas sample from being adsorbed by the stainless steel surface.
Technical parameters
1. Working pressure: 4Mpa, 20MPa.
2. Working temperature: -60℃～+80℃.
3. Material: 316L.
4. Medium: Sampling, storage and transportation of liquefied petroleum gas, propylene, butadiene and other gases and liquids.
5. Effective volume: 50ml, 100ml, 250ml, 300ml, 500ml, 1000ml, 1500ml, 2500ml, 5000ml, etc.
6. Customization on demand: Our company can customize sampling cylinders of different volumes and sizes according to user requirements.
7. Special treatment: Sulfur passivated cylinders with Sulfinert surface treatment technology are used for the analysis of PPB-level organic compounds.
Gas sampling cylinders
■ Sampling cylinders: Default includes bottle body*1, valve*2, pressure relief device*1, throat clamp handle*1.
Other accessories are optional according to the actual needs of users, such as quick connectors, reducers, pressure gauges, volume tubes, high-pressure hoses, cylinder brackets, explosion-proof disks, sealing glue, closed sampling systems, etc.
■ Sampling hose: It is composed of metal hose, connecting joints, and needle valves.
■ Connecting joints: It is configured according to the situation of the on-site sampling device.
■ PTFE inner coating: Spraying technology is used to spray PTFE (polytetrafluoroethylene) on the inner surface of the sampling cylinder to obtain a non-stick surface to prevent trace components in the sample from being adsorbed on the stainless steel surface. It can also improve the corrosion resistance of the cylinder and facilitate cleaning. The PTFE coating combines non-stick properties, heat resistance, chemical inertness, excellent insulation stability and low friction, and has comprehensive advantages that other layers cannot compete with.
■ High-pressure hose: The metal hose is a flexible connecting pipe for modern industrial equipment. The inner layer is a metal bellows and the outer layer is covered with a stainless steel braided mesh, which plays a role in strengthening the working capacity of the metal bellows and shielding static electricity. It has the advantages of corrosion resistance, high pressure resistance, high and low temperature resistance, and good sealing.
■Pressure gauge: installed at one end of the angle valve of the sampling cylinder, it is convenient to observe the pressure of the sample in the sampling cylinder in real time. When the pressure is too high, the operator can open the valve in time at the appropriate location to relieve the pressure, which further solves the safety hazard caused by the sharp increase in pressure in the sampling cylinder due to temperature changes. The user selects a suitable pressure gauge according to the sampling medium.
■Quick connector: specially designed for sampling cylinders, suitable for quick connection and disassembly of the device pipeline, with good sealing performance, no need to rotate, easy operation, and can be used with Swagelok.
■Volume tube: a reserved evaporation space of the required volume is provided in the sampling cylinder containing liquefied gas. If there is not enough evaporation space, a slight temperature rise can cause the liquefied gas medium in the cylinder to expand and cause the pressure to rise sharply, which will cause great safety hazards to the operator. The use of the reserved volume tube is based on SH/T0233 and ASTM D1265 standards. It is installed at the top outlet valve position of the sampling cylinder and screwed into the bottle body by thread. (The length of the reserved volume tube determines the size of the reserved space) The amount of evaporation space that needs to be reserved is determined according to the type of medium, which not only ensures the personal safety of the operator, but also avoids environmental pollution caused by the explosion of the bottle due to excessive pressure in the bottle.
■ Reducer: The reducer is a connection tool between pipes and pipes, and is a detachable connection point between components and pipes. It can conveniently and quickly realize the connection function between sampling equipment and production equipment, analytical instruments, tank trucks, etc.
■ Cylinder bracket: According to the actual needs of users, a series of sampling cylinder brackets have been designed and developed for laboratory staff to analyze, test, transport and store. Solve the problem of the placement angle and centralized transportation and storage of sampling cylinders.
■ Closed sampling system: The customized sampling system can realize a safe and efficient sampling process to meet your specific application needs. The optional panel has various configurations and * characteristics.
■ Other accessories: Our company also provides cylinder injection needles, pressure reducers, low-temperature needle valves, cylinder needle valves, filters, ferrule nuts and other accessories for users to choose from.

Seamless steel cylinders can be used for sampling in today's mainstream pressure devices, such as storage tanks, tank trucks, ships, production pipelines, etc. The following is a classic LPG liquefied petroleum gas and LNG liquefied natural gas sampling method.

Method Summary:

Use the sampling cylinder to obtain the liquid phase LPG sample from the device. First, clean the sampling pipeline and the sampling cylinder, and then fill the sampling cylinder with the liquid phase sample. Then discharge 20% of the sample volume of the sampling cylinder to retain 80% or less of the liquid phase sample (with a reserved volume tube).

Sampling steps

According to the required sample volume, select a sampling cylinder with a suitable volume. For sampling cylinders without reserved volume tubes, they should be weighed before sampling.

Flushing the sampling pipeline:

It is composed of a metal hose, a quick connector and a needle valve. Use the sampling pipeline to connect the inlet valve C of the sampling cylinder to the production device, and ensure that the control valve A, the discharge valve B and the inlet valve C are closed. Open the valve of the production device, then open the control valve A and the discharge valve B, and flush the sampling pipeline with the sample.

Rinse the sampling cylinder:
As shown in the figure, place it in an upright position with the outlet valve D at the top. When the sampling pipeline is flushed, ensure that the discharge valve B and the inlet valve C are closed. Open the control valve A, then open the inlet valve C, slowly open the outlet valve D, let the liquid sample fill the container, close the control valve A, discharge part of the gas sample from the outlet valve D, then close the outlet valve D, and use the method of opening the discharge valve B to discharge the residue of the liquid sample, repeat this flushing operation at least 3 times.

Sampling process:
As shown in the left figure, make the sampling cylinder upright with the outlet valve D at the top, close the inlet valve C and the outlet valve D. Close the discharge valve B, open the control valve A and the inlet valve C, let the liquid sample fill the container, close the inlet valve C and the production device valve, open the discharge valve B, and after complete pressure relief, disassemble the sampling cylinder and the sampling pipeline; thereafter, before adjusting the sampling volume, if a leak is found or any valve is opened, the sample should be scrapped.

Sampling equipment

Sampling cylinder: Standard configuration includes sampling cylinder body*1, valve*2, pressure relief device*1, handle*1.

Other accessories are purchased according to the actual needs of users, such as quick connectors, pressure gauges, reserved volume tubes, metal hoses, etc.
Sampling pipeline: It is composed of metal hoses, connecting joints, and needle valves.
Connecting joints: According to the situation of the on-site sampling device, our company can process and manufacture.

Adjust the sampling volume
Non-reserved volume tube type-weighing method: weigh the weight of the sampling cylinder filled with liquid sample, and determine the sample mass of 80% of the sampler volume at 20℃. Then put the sampling cylinder in a position where the liquid sample can be discharged, slightly open the outlet valve D, and release the excess sample.
Note: If the sampler cannot be weighed immediately, a small amount of sample should be released to prevent excessive pressure from being generated due to the expansion of the sample due to the increase in temperature. If equipped with a pressure gauge, the pressure change can be observed at any time.

Reserved volume tube type-discharge method: Place the sampling cylinder in an upright position, with the reserved volume tube at the top valve D, slightly open the outlet valve D, and the liquid will be discharged. As soon as the steam appears, close the outlet valve D to retain 80% or less of the sample. If no liquid sample is discharged after opening the outlet valve D, the sample should be scrapped and resampled.

Leakage check
Immerse the sampling cylinder filled with gas in water to check whether there are bubbles. During the sampling period, if a leak is found, the sample is scrapped.

Sample storage
The sample should be stored in a cool place as much as possible until all tests are completed. To prevent the valve from being accidentally opened or accidentally damaged, the sampling cylinder should be placed in a special frame or a valve protection nut should be used.

Packaging and transportation
1. Use wooden boxes or cardboard boxes for packaging, and fill the box with foam or sponge.
User instructions:
1. The sampling personnel need to determine the location of the sampling point in advance in order to obtain a representative sample. The sampling personnel are required to understand safety technology and have corresponding experience and skills.
2. This method is not applicable to all media. Users of this manual need to be able to give priority to appropriate and safe methods. This is the responsibility of the relevant sampling personnel.
3. During the sampling process, due to the different structures of LPG devices, there are many complex factors and changes, so it is very difficult to specify a unified sampling method to obtain a representative typical sample.
4. If the equipment storage tank volume is large, the sample can be circulated before sampling to achieve uniformity. If the sample is in a flowing state, when sampling on the equipment pipeline, the pressure in the pipeline should be higher than the standard atmospheric pressure to avoid two-phase conditions.
5. This sampling method cannot describe all sampling situations clearly enough, and it needs to be supplemented accordingly based on judgment, skills and sampling experience. Extra caution and accurate judgment are the abilities required to obtain a sample that represents general characteristics.
6. Because the sampling process involves danger, the sampler should conduct sampling work with the assistance of staff who are familiar with safety measures.
7. During the sampling process, pay attention to safety when discharging toxic and harmful samples, handling waste liquids and vapors. The discharge point must have safety measures and comply with safety and environmental protection regulations.
8. Avoid sampling from the bottom of the tank. Sampling personnel should avoid contact between liquefied petroleum gas and skin. They should wear gloves and protective glasses to avoid inhaling vapor.
9. The liquefied petroleum gas discharge device will generate static electricity. Before sampling until the sampling is completed, the equipment should be grounded or connected to the liquefied petroleum gas system.

Accessories selection

The stainless steel sampling cylinder adopts one-time hot spinning, pickling and passivation and other technical processes. Due to the complex sampling site environment, different laboratory analytical instruments, and the diversity of samples that can be collected by the cylinder, it is difficult to unify the fixed sampling cylinder accessories. Users need to purchase according to actual needs and communicate with customer service.

■PTFE polytetrafluoroethylene inner coating:

The inner surface of the sampling cylinder is sprayed with PTFE (polytetrafluoroethylene) to obtain a non-stick surface to prevent trace components in the sample from being adsorbed on the stainless steel surface. It can also improve the corrosion resistance of the cylinder and facilitate cleaning. The PTFE coating combines non-stick properties, heat resistance, chemical inertness, excellent insulation stability and low friction, and has comprehensive advantages that other layers cannot compete with.

■Metal hose:

Metal hose is an indispensable flexible connecting pipe for modern industrial equipment. The inner layer is a metal bellows, and the outer layer is covered with a stainless steel braided mesh, which plays a role in strengthening the working ability of the metal bellows. It has the advantages of corrosion resistance, high pressure resistance, high and low temperature resistance, and good sealing.