PVT cell which carried out the study pressure-volume-temperaturacelda PVT) is basically a hollow stainless steel cylinder about 600 cm3 capacity, has provided a window for visual observation of the bubble pressure so the process Differential release consisting of gas extraction can be done by keeping the constant bubble size.

It is designed to withstand high pressure and temperature changes (10000 psi and 350 ° F), the cell has a glass window with an opening of 4.4 cm in length and 0.64 cm wide, to observe the gas-oil interfaces mercury. The window glass has a thickness of about 2.54 cm and is housed in the main body settled with stamps and adjusted by internal screws.

The inlet valve to the cell is in the top together with a tube of 0.32cm diameter stainless steel that takes the form of a solenoid connection before entering the cell.

The cell is equipped with two arms to hold in your bathroom and can rotate fully without friction. The valve of the cell is needle that allows the appropriate section to control the formation of foam and come from the removal of any part of the liquid phase with gas in solution. The location of an exit visible on the top of the cell allows the rapid removal of the gas leaving a very small fraction of a cubic centimeter of gas without the danger of the gas-liquid equilibrium is altered by the output of liquid the cell.

The temperature control is done through a thermostat located in the control panel and using an oil bath.

partes de la celda PVT

Preparation of Cell PVT
If the cell is with mercury or other fluid is drained into a container that can hold a volume greater than 600 cm3, as is the ability of the cell. Then proceed to clean with gasoline or other fluids non-corrosive solvent. You should not release (remove) valves for cleaning. The solvent is injected or sucked air pushing to empty. Strongly stirred cell. It is enough two or three washings with 100-200 cc of solvent. It drains all
solvent and dry circulating air.


Cell elastomer seals PVT
One of the most widely used seals and stamps are modern type “ring.” If a label like “ring” was used in a glass window, would experience little difficulty. Accommodation such a bad seal in the cell would result due to temperature change, a change in the reading volume in a quarter of a cubic centimeter or so.

Signet ring cell square section of the PVT
An improvement of the seal type “ring” seal ring is square. This acts similarly to the label “ring”, but because of their difference cross section, reduces the error caused by the accommodation of signet ring. ” This seal consists of two retaining steel square section placed in side by side and sized so that the space between is occupied by the retainer ring seal square.

Seal compound PVT cell
A composite seal is satisfactory compared with previous ones. Is a label consisting of a thin steel plate in a square interior which has been inserted a vulcanized elastomer resistant to chemical attack with trapezoidal section. Has properties of both seal against the pressure inside the cell, but not necessarily sealant if the cell is evacuated. The steel should be cleaned with a stream of wood that the elastomer can be cured in the settlement of the window.

These brands are safe, provided that they do not extend into the sealed area of the elastomer insert. The seal compound requires a torque of 5 lb-ft for external adjustment screws and 15 lb-ft internal screw adjusters. Any sealing method which is used in synthetic rubber or elastomer resistant to chemical attack, are always subject to attack over time. Your life depends mainly on the chemical composition of fluids in the analysis, pressure and operating temperature.

Phenolic resin seal the PVT cell
Is more durable and better seal the constant volume is obtained by a board of canvas reinforced phenolic resin, which is manufactured under the trade names Bakelite, Formica, TEXOLINE, Micarta, etc. This seal was used in cells built in the last twenty years. The seal consists of a board of 0.159 inch thick set with precision in the settlement of the window of the cell. Should take the greatest care in carving and this stamp set, so that its polished surface is not damaged, for example scratches, cracks, or bent.

The high temperature and pressure mounting to which the board is subject will not produce a significant effect on its compressibility and deformation. Its resin sealed most of the small marks, scratches on the hole in the window and onto the glass.

The material used for these meetings should be carefully selected. Can be used 2 sheets of Teflon of 50 microns (0.002 inch) thick, which are placed on each side of the resin. When the placement of the phenolic resin or phenolic resin, Teflon is used, “a torque of 10 lb-ft would be used for the adjustment screws and 50 Lb-ft screw adjusters.”

Rusk bath for visual cell has an internal diameter of 45.72 cm. The bathroom has a capacity of 18 gallons and a maximum current consumption of 3700 watts. In addition, a product that contains the heating elements and agitator, is equipped with an auxiliary camera. A wall-mounted pump is used to raise or lower the oil level in the bath and exposing the cell window completely in the oil when the equilibrium temperature is reached.

The bathroom consists of a controlled temperature oil circulating system. The bathroom should not be operated without oil circulation to prevent overheating of the heater elements. For this reason, the main switch is connected to the motor and agitator. The use of a switch could triple the warming unit inoperable, but the mixer will work as soon as the switch is on.

It is essential that the facility has a flat base to rest on wood for easy cleaning of the bottom, at its base there are 4 holes in each corner requiring an area of 61 x 61 cm.

The bathroom must be connected to a power line in compliance with the relevant specifications on the control panel and grounding connections are made on the main switch. When the cell is immersed in the bath is ready for testing.

Operation of the bathroom: The bathroom is filled with commercial oil very resistant to temperature (SAE 30) with the main switch is on, so the motor of the agitator went into operation and control of the heat off. Warming can now be operated. To get a quick bath temperature, triple switch is set to HIGH (high), and the thermostat is on, so it comes into operation the controller of heat. HIGH is used solely to achieve the desired temperature.

The control panel is responsible for certain cell functions such as shaking the cell, raise or lower the oil level, temperature control.

Indicates the thermostat operation.

Controls the heat input from the heating system.

It’s a three position switch, with the top to raise the middle is neutral, lower is to lower it.

Drives the agitator that allows the circulation of hot oil within the cell.

Graduated scale to set the desired temperature, each division is 1 ° F.

Provides heating rate to the system giving warmth and has 3 positions: high, low and medium.

Provides the necessary energy and drives the agitator at a time.

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