DE29622800U1 - Device for recording the liquid gas transfer - Google Patents

Description

Device for recording the liquid gas transfer

The invention relates to a device for detecting a liquid gas transfer quantity from a first tank to a second tank while returning gas from the second tank to the first tank as cushion gas.

The transfer of liquefied gas is necessary, for example, when transferring from rail tankers to stationary containers, when loading and unloading gas tankers and similar facilities. In the future, aircraft refueling may also be an option.

In many cases, weighing is not possible for a variety of reasons, but it should still be possible to make a clear statement about the amount of gas transferred.

. The object of the present invention is therefore to create a device with which the effective liquid gas delivery quantity can be recorded without direct weight measurement.

The solution to the problem is achieved with the device mentioned above in such a way that
a) a recording of the flow volume per unit of time from the first to the second tank and from the second to the first tank

is provided,

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b) the temperature of the gas flowing from the first to the second and from the second to the first tank is measured ,

(c) furthermore, a calculation of the associated gas quantities per unit of time is provided for and

d) the calculation of the difference in the gas quantity and the integration of the difference over the transfer period is provided for.

In this way, for example, the amount of gas delivered can be obtained in tons. Depending on the type of gas and the assumptions about accuracy, the gas can be considered as an ideal gas or as a real gas and limit values can be taken into account. The entire calculation process can be carried out in a freely programmable control device to which the corresponding values of pressure, temperature, etc. are fed. In terms of cost, the use of a simple standard automation device, e.g. the SIPART DR 24 device from Siemens AG, is the cheapest. This device was designed for simple control and regulation tasks, but surprisingly, with appropriate programming, it can also be used to solve the task according to the invention.

The invention is explained in more detail using an embodiment shown in the drawing:

As can be seen from the drawing, liquid gas is taken from a tank wagon 1 via a tank wagon unloading pump 2 and fed to a tank 3. From this tank 3, liquid gas is

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• · ♦··· ♦·

Compressor 4 cushion gas 5 is returned to the tank car 1 in order to avoid explosion conditions.

For the gas flowing from the tank wagon 1 to the tank 3, devices 6 for volume measurement and 7 for temperature measurement are provided. In addition, recording devices 8 for pressure, 9 for volume and 10 for temperature are available for the cushioning gas. The corresponding values for temperature Tl and volume Vl of the liquid gas 1 flowing from the tank wagon 1 to the tank 3 are supplied to a limit curve calculator 12, e.g. the SIPART DR 24 device mentioned above, which determines the amount of gas flowing per unit of time in standard cubic meters per hour. The output curve of this calculator can advantageously be non-linear.

The corresponding values of the backflowing cushion gas 5, i.e. pressure P2, volume V2 and temperature T2 are fed to a simple computer 11 for ideal gas, and from this the amount of gas delivered per unit of time is calculated. At the same time, these data are also fed to a limit curve calculator 13, e.g. the SIPART DR 24 mentioned above, which can be used under certain conditions instead of the simple calculator 11 or calculator part. The selection between the two computers or calculator parts is made by a switch 14. The values obtained are converted to liquid gas in a module 15. The difference between the gas quantities flowing back and forth per unit of time is then calculated in a difference generator 16, namely in standard cubic meters per hour, i.e. in gas quantities per unit of time. These gas quantities are integrated in an integrator 17, i.e., 0 this results in the standard cubic meters of gas quantities delivered.

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This process can be controlled by counters 18 and . The gas quantity delivered in standard cubic meters is then advantageously converted into tons in a device 20 and then shown in a display 21 with a corresponding control printout.

In their actual form, the individual modules mentioned above are normally implemented in a computer or in a freely programmable control unit. They are broken down into individual modules for the sake of clarity.

Claims (4)

GR 96 G 3599 DE Protection claims 1. Device for recording the liquid gas transfer quantity from a first tank to a second tank with return of gas from the second tank to the first tank as cushion gas with a) a recording of the flow volume per unit of time (Vl, V2) from the first to the second tank (1,3) and from the second to the first tank (3,1), b) detecting the temperature (Tl,T2) of the gas flowing from the first to the second tank (1, 3) and from the second to the first tank (3,1), (c) a calculation of the associated gas quantities per unit of time and d) Calculating the difference in gas quantities and integrating the difference over the transfer period. 2. Recording according to claim 1, characterized by the calculation of the standard cubic meters delivered per unit of time, difference formation and integration and conversion into weight quantities. 3. Device according to claim 1 using a freely programmable controller. 4. Device according to claim 1 using a standard automation device, which allows the parameterization of limit curves.