Alternative classification of electromagnetic flowmeters:

Electromagnetic flowmeter according to flow sensor structure classification can be divided into short tube type and insertion type. Short tubular structure such that the structure of the conventional electromagnetic flowmeter electromagneticfuel meters, flow sensor with measuring pipe is connected to the piping system. Insertion electromagnetic flowmeter sensor is an electromagnetic velocity sensor is substantially, the excitation coil and the electrode assembly into a rod, inserted from the opening in the pipe under test, the measured flow rate converter preset factor multiplication pipeline and area requirements hydrochloride take traffic. In addition to single-point "point velocity", there are side more "run-off speed" are.
Electromagnetic flowmeter according to this classification method can be divided into contact and non-contact electrode electromagnetic flowmeter electromagnetic gasoline flow meter electrode. Electrode contact type electromagnetic flowmeter electrode is in contact with the liquid EMF conventional structure, typically a pair of electrodes, large diameter instrument industry useful two pairs of electrodes. Non-full tube EMF is also useful for three pairs of the motor or strip electrodes. Non-contact electrode type electromagnetic flowmeter is a large area of the electrode close to the lining (or insulation measuring tube) outer surface to capacitive coupling to pick up traffic signals, electromagnetic flowmeters measure the capacitance detection method than the short-contact electrode capacitance electromagnetic flow meter, the principle fancy diagram. Preamplifier placed alone in the sensor electrode, high excitation frequency EMF than usual, for 50 / 2Hz, who also has more than 100Hz. This class does not produce meter electrode passivation, oxidation and catalytic role of the electrode surface effect of noise, but also the opportunity to slurry flow noise and the noise does not exist. Surface covering oil and other non-conductive layer or a thin layer of insulation lining will not affect the measurement; but if it is a conductive film overlay the meter will no indication. Meter factory, said some foreign instruments such as non-electrode electromagnetic flowmeter.

Tanker reasonable error and anti-cheat features

In accordance with the relevant provisions of the tanker maximum permissible error ± 0.30%, each tanker is equipped with a tamper-resistant feature, as long as five times more than this range, it will automatically lock. Traffic center will regularly tanker filling stations for technical examination.
A former mobile fuel dispenser inspection pass rate of about 70 percent fuel "second look"
There is a reasonable measurement error tanker tankers have all anti-cheat tank automation system
It is reported that the tanker is to rely on internal metering metering chamber means to complete, however, due to the usual wear and tear frequent use, it may cause some errors.

How do small tanker maintenance measures:

1.A combination pump dispenser is only suitable for small underground auto fuel dispenser, such as the use of high tank, exhaust pipe Maoyou phenomenon occurs, then make sure the exhaust pipe blocked.
2. Maintenance of electrical parts must be cut off the power, should not live overhaul. Do not damage the surface when you open the explosion-proof box. Intraluminal foreign body should clean dust explosion at a clean re-install the cable should be well sealed, metal pads, gaskets can not be lost, not the number of missing screws, tighten and reliable performance to ensure proof electrical components.
3. To avoid the use of oil gun oil filler pipe percussion gun is not normal operating oil container, such as by pressing the switch, to avoid damage to the oil gun, causing oil spills. Regularly check and tighten the stop screws on the injection tubing, injection tubing to prevent the roots loose, damaged.
4, the relief valve on the machine pumps and pump combination on the adjustment screw for adjusting the pressure of the pump, thereby regulating the discharge of small oil petrol dispenser. Has been adjusted at the factory. After long-term use, such as the discharge of oil dropped, the adjustment screw can tighten inward to increase the pump pressure, but not more than 0.3MPa, the exhaust oil to meet the requirements.
5, underground storage tanks be cleaned regularly to keep the oil clean.

Tanker structure and function in accordance with the differences can be used for a variety of categories.

In terms of the size of the oil transport capacity can be divided into general transportation capacity (the amount of oil is 40 ~ 60L per minute) of the tanker and the large flow (the amount of oil is 80 ~ 90L per minute) natural gas dispenser.
If you press the number contained in each refueling tanker refueling gun unit or can be divided into single gun tanker, guns and more guns refueling tanker.
By refueling tanker pump source can be divided into self-priming and submersible pump dispenser containing the.
In addition, according to the different functions of the special auxiliary tanker have mobile tankers, tanker car, suspension-free island refueling system with refueling vapor recovery function, adjustable set a different label contaminated fuel oil machine, and the host computer networking or controlled tanker, and China's Fiscal diesel fuel dispenser and so on.

Troubleshooting relief valve

In practical use, in order to maximize the effectiveness of pilot relief, protection and control vehicle identification systemaccurate and timely diagnosis, excluding pilot type relief valve failure is the key part.
Pressure limiting instability: pilot pressure relief valve limiting instability, manifested as low or high pressure hydraulic systems, hydraulic actuators action unable or tubing, pump, valve burst. Cause of this failure reasons: improper pressure adjustment; pilot valve spool spring bend or soften; oil too dirty or poor oil flow. Appropriate measures are excluded: readjust; calibration padded or replacement; replacement, cleaning. Pilot pressure relief valve limiting the gradual onset unstable failure, pilot-type relief valve failure.
Pilot type relief valve failure, will cause the injection molding machine inoperable. According to the phenomenon, analysis of the reasons are: the pilot valve spool spring break; Yin Nicon blockage; pilot valve port seal bad; the main valve stuck and so on. Corresponding exclusion measures are: replacement or broken at the flat washers to emergency use; cleaning dredge; grinding or the oil circuit breaker to emergency use; grinding, cleaning.
For all aspects of small tanker spill analysis. Enhance the use of small tankers. Small tanker used very widely, so it is necessary to understand the work of the various parts of a small tanker. Small tanker spill analysis works well for your relief valve failure. Are constantly deepening the internal structure of a small gas station management system. Small tanker analytical works.

Role tanker hydraulic components

Tanker hydraulic components including: station management system, oil separator, measurement converter, oil gun, depending on the oil, electric valves and hydraulic lines.
There pump vane pumps, internal gear pumps and submersible pumps. Among them, the submersible pump is a hydraulic power source in recent years, China's gas stations began to be used. Generally use centrifugal submersible pump, is placed inside the tank. Imported submersible pump dispenser is higher than atmospheric pressure.
The main function of oil separator is to pump oil in the exhaust gas separation and discharge, the transport to the measurement of oil-free gas converter ensure accurate tank automation system.
Measurement converter measurement converter with a metal piston, piston measurement converters and soft soft double piston measurement transducer.
Grease guns can be divided into ordinary grease guns and automatic nozzle.
The electric valve is a solenoid valve and a double-flow dual flow solenoid valve.

The role of small tanker spill

For the analysis of the various parts of the small fuel management systems, thereby enhancing the understanding of the small tanker. Introduced the case of a small tanker vane pump and oil pump, etc. It should be noted in the previous article. Works as well as the analysis of fault diagnosis now we look at the role of the relief valve in the pump and its main role.
Relief role is:
High pressure relief valve within the pump chamber of a door leading to the low pressure chamber, which is mainly played the role of protection and limit the maximum pressure of the hydraulic system of the fuel monitoring system, and can adjust the output of tanker traffic.
Relief works:
When the motor is started, the oil pump, pressure oil from the oil pump flow positive zone and oil separator P relief valve port open at this time if the oil gun, pressure oil to the oil separator, pressure relief valve is closed, the pump the positive pressure and negative pressure zone pass each other; when the oil gun is closed, the pressure in the hydraulic system rises rapidly, the oil pressure relief valve overcoming the force of the spring, the spool shifted to the right, high pressure oil through the relief valve P and O port flow to the pump suction area, to achieve a petrol pump cycle.
Increased spring force, can increase the maximum pressure of the hydraulic system. Without relief, when the hydraulic system pressure is higher than a certain value. System most book weak links will be destroyed.
When the pressure relief valve adjustment screw clockwise twist, the pressure required to open the relief valve increases, most or all of the flow of oil and gas separator. Output increased tanker traffic; when the adjusting screw counterclockwise twist, the pressure required to open the relief valve is reduced, some oil through the relief valve back to the pump suction area, external output flow decreases.