Account in units of volume and weight
Measurement systems “Struna” – is automation of measurement of parameters of light petroleum products and LPG at reception, storage and operational control of reservoir park of petrol stations and storage depots.
Systems are intended for measurement of level, temperature, density, pressure, calculation of volume and mass of light petroleum products and light petroleum gas (LPG) in single-wall and double-wall reservoirs, signaling about presence of underproduct water, increase of a level of fire and ecological safety, automation of the process of account of petroleum products at petrol stations and storage depots. Systems can be applied in food and chemical industries.
Measurement systems “Struna” are certificated as means of measurement in State register of the means of measurement of Ukraine and Russian Federation, have explosion proof “intrinsically safe electric circuit of level ia” and approves a conformity with the requirements of standard series GOST R 51330.0-99, GOST R 51330.10-99, as well as IEC 60079-0-98, IEC 60079-11-99.
Measurement systems “Struna” provides:
- Precise remote measurement of level, density, temperature, pressure and mass of fuel and LPG in reservoirs (as well as benzines, diesel, oils, spirits, kerosenes, CNG, gas consensate, solvents).
- Calculation of volume of petroleum products in reservoirs according to graduation charts of reservoirs.
- Calculation of mass of petroleum products with limits of permissible relative error ±0,65% (methodic of measuring is registered).
- Possibility to automate and provide detailed control over account of movement of petroleum products and LPG on one or several petrol stations (or storage depots) at simultaneous usage of dispensing systems.
- Automatic control over leaktightness of single-wall and double-wall (with liquid filler) reservoirs with switching on of light and sound signaling.
- Gas pressure control in reservoirs with LPG or in interstitial space.
- Control over presence of underproduct water in reservoirs.
- Prevention of overflow of fuel at filling the reservoirs by giving control signals to switch off the pumps, switch on (off) light and sound signaling.
- Automatic calibration of reservoirs using special software.
- Control of under explosion dangerous concentrations of flammable gases and steams with switching on signalling and actuating mechanisms.
- Self diagnostics of functioning and metrological characteristics of the system in all modes of operation, including control over dynamics of level changing at reception of petroleum products that provides at failure possibility to switch off pumps or closing of electromagnetic valves and also giving signals on failure.
- Indicating of measurement results and calculation of parameters on autonomous indicator, output of information into the system or program of the user through a standard interface RS-232C, RS-485, USB.
- Metrological checking without dismantling of PPC with a help of internal means.
- Significant reduction of downtime of petrol stations at changing the working shifts.
Technical characteristics of the system:
| Range of level measurements (without density meter), mm
|
from 120 to 4000 |
| Range of level measurements (with “surface” density meter), mm |
from 200 to 4000 |
| Range of level measurements (with “submersible” density meter), mm |
from 120 to 18000 |
| Range of level measurement (for calibration of tanks), mm |
from 0 to 4000 or from 0 to 9000 |
| Margins of allowed absolute error in a range up to 4 meters, mm |
±1,0 |
| Margins of allowed absolute error in a range more than to 4 meters, mm |
±2,0 |
| Resolution, mm |
±0,1 |
| Exploitation temperature range of PPC, °С |
from -40 to +55 |
| Limits of permissible absolute error of temperature measurement, centigrade degrees |
±0,5 |
| Ranges of density measurement, kg/m3: |
|
| - 1 range (LPG) |
from 499 to 599 |
| - 2 range (petrol with 80 octane number) |
from 690 to 760 |
| - 3 range (petrol with octane numbers 92, 95, 98) |
from 715 to 785 |
| - 4 range (diesel fuel) |
from 810 to 880 |
| Limits of permissible absolute error of density measurement (with “surface” density meter), kg/m3 |
±1,5 |
| Limits of permissible absolute error of density measurement (with “submersible” density meter), kg/m3 |
±1,0 |
| Limits of permissible relative error of measurement: |
|
| - Mass of petroleum product up to 120 tons, % max |
±0,65 (±0,3 typical) |
| - Mass of petroleum product over 120 tons, % max |
±0,5 |
| Signalling at presence of underproduct water at level (for fuel stations), mm |
25 |
| Range of measurement of underproduct water level (for petroleum storage depots), mm |
from 80 to 300 |
| Limits of permissible absolute error of water level measurement (for petroleum storage depots), mm |
±1,0 |
| Range of overpressure measurement, MPa |
from 0 to 1,6 |
| Limits of permissible reduced error of pressure measurement, % |
±1,0 |
| Quantity of controlled reservoirs (by 1 central unit) |
up to 16 |
| Cable length from each reservoir to the operators' room, not more, m |
1200 |
| Parameters of control channels in a Control Unit: |
|
| - power circuits (optosemistor) |
~220V; from 0,1 to 0,5A |
| - power circuits (dry contact) |
~220V; from 0,01 to 0,1A |
| - low power relay circuits (dry contact) |
=27 V ; from 0,1 to 0,5A |
| System feed |
220V +10 -15 %; 50 Hz; 0,6А |
Structure of measurement systems “Struna”:
Central part:
- Computing device (CD) (dimensions of case 690 x 380 x 140 mm), installed inside a premise and consisting of:
- computing block (CB), that has a degree of explosion proof ExiaIIB, intended for collection, primarily convertion and processing of data on parameters of reservoirs (up to 16), preparation of information to indication in measurement units and communication with external systems, computer, networks;
- specialized power supply unit (PU), that has a degree of explosion proof ExiaIIB;
- blocks of clamp connections (BC), intended for connection of cables from primary parameters convertors (PPC).
-
Indication block (IB), desktop case installed inside a premise, intended for indication to operator parameters of petroleum products in reservoirs, providing signals on state of the system and also input from keyboard values of parameters settings and setting of operation modes. Dimesions: 190 x 135 x 52 mm;
-
Interblock cablings, interface convertors and exploitation documentation (ED).
Peripheral part:
-
Primary parameters convertor (PPC) with sensors of level, temperature, density, pressure and underproduct water (according to variant of execution). Made in explosion proof case, has a degree of explosion proof ExiaIIB and is installed in reservoirs.
-
Control unit (CU), which is installed inside the premise and is intended for programmable switching on and off of siren (notifiers) (light and sound) and also execution mechanisms (valces, pumps). Dimensions of a case: 305 x 178 x 75 mm.