Calculation and selection of the restriction device

Calculation and selection of the restriction device. Calculation of the restriction device.

The calculation of the restriction device is based on the determination of its diameter d under the following conditions that should be exactly done - standard maximal pressure drop should be selected the bigger one, i.e. during this fact the coefficient is more stable - standard maximal pressure drop should be selected as less as possible, because of the increasing of the pressure drop the irreversible pressure drops module of the diaphragm is specified by the condition - the error of the calculation shouldn t exceed 0,1. The calculation of the diaphragm can be performed with the help of the previous equations and the following table ,1650000,610,413128,582499,83670,0065160 01058,650000,610,326114,352499,86650,005 325001822,950000,610,261102,302499,91110 ,003640003142,750000,610,20792,0072499,9 8560,000663005222,650000,610,16581,29425 00,10020,0040 Table 2 Calculation results Calculation results that are the most suitable for the selection of the diaphragm are shown in the table2 with a help of thick lines under. This choice is done by the following conditions 1 The given pressure of the irreversible loses is. From the received calculation other rows also follow this condition. 2 где boundary Reynolds s factor. 3.The meaning of the module is maximally approximated to the optimal meaning . 4.The error of the calculation should be. In our cas. Let s define the basic geometrical dimensions of the diaphragm are Selection of the restriction device Rules PD-50-23-80 regulate the following requirements to the standards of the restriction devices 1.Construction of the restriction device and method of its mounting should have the ability for the periodical inspection for the check whether this device follows the standards. 2.Measurement of the pressure drop in the restriction devices performs through the cylindrical hole or through two ring cameras.

Hence from the condition of the pass and the conditional pressure, under ГОСТу-26969-86 we will select the diaphragm ДКС 10-80. For the collar selection фланец СУ we will use ГОСТ 12820-80. The restriction device consists of the diaphragm and cameras.

There also are the collars, main pipeline and the measuring tube. The diaphragm should be done with a high accuracy, due to this the Reynolds flow factor changes, and this in it s turn influences on the stability of the expense factor and etc. The level of the diaphragm smoothness from the side of sharp edge should be equal to 6-7.The choice of the pressure can be performed through the nozzle. патрубок For the provision of the high accurate measurements with the help of the CS, it is not quiet enough to calculate it with a high accuracy. It should be also fulfilled the requirements, that are presented for the restriction device 1.The restriction device should be housed on the straight part of the tube. On these parts the cut-off fixtures запорная арматура cannot be placed, the turns of the pipe are not available. 2. The strict observance of the coaxial alignment between the pipeline and CS. 3. On this part of the pipeline there shouldn t be any local resistances. 4. Place CS relatively to the differential manometer-flowmeter according to the normative documentation.

Selection of the pressure drop is performed in the places, according to the change of the environment. 1. The construction of the restriction device and the method of its housing should provide the ability of the periodical inspection for the check whether this device follows the standards. 2. Measurement of the pressure drop in the restriction devices performs through the cylindrical hole or through two ring cameras. 3. The diaphragm should be done with a high accuracy, due to this the Reynolds flow factor changes, and this in it s turn influences on the stability of the expense factor and etc. 4. The level of the diaphragm smoothness from the side of sharp edge should be equal to 6-7. 5. The choice of the pressure can be performed through the nozzle. патрубок In the form of the restriction device we will take the camera diaphragm ДКС-10-80 ГОСТ 26969-86 that is drawn on the figure 1. The size of the diaphragm we will chose according to the conditional pass and conditional pressure by the ГОСТ. For the housing of the diaphragm on the pipeline the collars are used ГОСТ 12820-80. The diaphragm should be housed on the straight part of the tube. On these parts the cut-off fixtures запорная арматура cannot be placed, the turns of the pipe are not available.

Due to all these rules the restriction device will have very high measurement accuracy.

Selection and description of the flowmeter assembly work During the change of the natural gas expense due to the task of this paragraph the differential manometer 4 should be placed higher then the restriction device 1. The angle should be 110 on all the position of the horizontal parts of the pulse line in the side of the selecting device.

For blowing through of the system on the pulse lines the blowing through valves продувочные вентили3 are placed.

These blowing through valves are also placed in all high points of the connection lines in the case of inability of the one side angle construction.

The section of the pressure can be stopped with a help of the equation valve, if it exists.

Figure 2.