1. Fuel Dispenser Malfunction and Solution
Before the maintenance, first we must fully understand the failure phenomena, and do the analysis and correctly judge the point of failure. To determine the point of failure to follow the general " Look after the split, the easier issues first " principle.
|No seal well in pipeline||Pipeline Maintenance|
|Motor does not turn or reverse||Overhaul motor, circuit and control system, will swap any two FireWire|
|Belt has come loose||Adjust tensioner or replace V-belt|
|Filter is blocked||Clean the filter|
|The outlet valve of oil-gas separator is broken, can't open||Clean the outlet valve to make the trim running well|
|Conical valve of oil-gas separator can't close tightly.||O verhaul the conical valve.|
|Relief valve spring too loose||Adjust the relief valve to replace damaged parts|
|Blade wear and tear,spring broken||Replace parts|
|Flow meter broken||Repair flow meter|
|The sealing elements in the hydraulic system damage||Replace the seal|
|Leak in pipeline||Check pipes, excluding leakage|
|Exhaust pipe blocked oil and gas separator||Clean up the exhaust pipe|
|Conical in oil gas separator can't close tightly||Check the conical valve|
|Floater valve can't close tightly||Check the floater valve|
3.) Oil leak from exhaust pipe
|The ball-type float off||Install the ball-type again|
|Ball type float or Oil return float get into oil.||Chang float|
|Broken washer between oil gas separator body and cover||Change washer|
4.) Measurement error
|Parts inside of flow meter wear and tear (including worn-out mechanical parts and rubber aging )||Adjust the meter's adjustment screw, replace the damaged parts|
|Sensor pole damage||Change the sensor board|
|Main board damage||Replace main board|
5.) Do not start to work
|Too low power source||eliminate power circuit failure|
|Power board damage||Overhaul or replace power board|
|Keyboard damage||Overhaul or replace key board|
|SCR board is damaged||Replace the SCR board|
|Main board is broken||Change main biard|
|motor damage||Change motor|
6.) No stop
|Keyboard damage||Overhaul or replace key board|
SCR board is damaged
Replace the SCR board
Main board is broken
Change main biard
2. Fuel pump malfunction
Pump failures common phenomenon is:no oil supply, oil supply shortage, leakage, abnormal noise and vibration increase, oil and gas can not be separated from the exhaust pipe and so on.
Following is the analyzing and solution regarding above malfunction.
1.) No fueling or oil supply shortage.
Import vacuum pump is not less than 60kPa, to ensure the absorption process of the vertical height of 4 meters and horizontal distance of 60 meters, if import vacuum is less than 40 kPa (ie negative pressure is not enough) there will be failures of no suction. Similarly, leakage inside the pump also contributed to the negative pressure. The gap of the tangent between rotor and stator is too large, the gap between the rotor face and the front cover is too large (天the gap between the gear inside and outside of vane type gear pump and pump cover is too large), relief valve was not closed tightly or trim stuck will cause leak inside of pump increased. In addition, the float valve seat closed lax, allowing gas to get into the pump can also result in negative pressure.
No fueling or oil supply shortage, complete overhaul method is as follows:
① First, an external overhaul.
Check whether the motor turn, reverse, or speed is too slow, or V-belt slipping and so on. If the above phenomena is the motor turns too slowly, check if the external power supply voltage is normal, and check if the motor or SCR damaged.
② Following the above examination found no fault can be checked and whether there is leakage phenomenon from the filter cover and at the junction sealed, whether the filters are too dirty and the exhaust pipes have suction phenomenon. If there are leak phenomenon should be re-installed tight or replace the corresponding parts, clean or replace the filter (modular type gear pumps have inlet and outlet filters), oil return valve trim seat or float valve component.
③ If still no found failure, then consider whether the relief valve body is stuck, close lax, or seat loose, as well as a valve is not open die rust, cleaning or replacing the corresponding parts of re-assembling the corresponding parts.
④If you have not found failure, it can be judged as seriously worn or broken on blades, shaft sets wear and tear. Open and inspect the rotor as well as stator blade, is the blades are serious wear and tear, general to be replaced (modular type gear pump, consider if inside gears and bushings wear and tear serisously)
External leakage is oil from the hydraulic system to leak outside the system, external oil pump leak not only affects the working performance, but also to increase insecurity in the environment, outrigger pump shaft leakage from the roots, mostly caused by oil seal failure, should be replaced, the replacement seals can not be loaded reversed, lips should go pump cavity, Also check the reason lead to seal failure: such as the relief valve and V-belt adjustment of the tight and so on. External leakage also may cause by all sealing gasket damaged and 0-ring seal damaged or too long time service to performance, discovery should be the timely replacement of sealing components.
3.) Abnormal increasing noise and vibration
Reason of fuel dispenser can be attributed to a few steps from the following considerations:
① filter is too dirty to allow oil to get into the pump enough, that is shortage of fueling, resulting in increased noise and vibration, It should be cleaned or replaced (gear pump with into let and outlet filter.)
② Check whether the relief valve spring is too tight or stuck not to open. Cleaning relief valve, and to exclude obstruction causes, can not blindly turn relief valve spring tight to get high flow rate. It will make the system pressure is too large, noise and vibration increase, reducing service life.
③ If you have not solve the problem yet, consider the gap between pump rotor and tangent of stator is too small (less than 0.02mm) or no gap, the space between the rotor face and the front cover is too small (less than 0.02mm), the space between the rotor shaft and the former, back cover bearing bore gap is too large (this gap is 0.035 ~ 0.050mm),blade side (with the blade slot has a relatively sliding surface) flatness error is too large, or flatness error of blade slot is too large, broken blades are stuck combined vane pump lead to generate noise, noise or vibration increased. The solution is to re-grind the surface or replace the corresponding parts. Combined gear pump can be considered: the space of outlet and inlet gear is too small gear, the space of internal gear external gear and pump cover end is too small, the space of inner gear sleeve is too large caused by wear and tear, pressed on pump cover bolts are no uniform, and pressure on inside gear is not uniform
④ Resonance phenomenon is also one of the reasons lead to noise and vibration, the vibration frequency of motors and pumps and the pulse frequency from hydraulic system is similar to the natural frequency of fuel dispenser, it will resonate, which led to this result, method of examination is to touch different parts of the fuel dispenser under power on, when touched a certain part of the fuel dispenser to evidently felt that the noise down, can be judged is the resonance. The solution is to add rubber pad to reduce vibration on the combination of motor and chassis department, on the combination of fuel pumps and chassis. Also present vapor in the pipeline sound uneven, fueling stop and go
⑤ some oil with poor self-lubricating, when the new machine to fueling this kind of oil, due to friction, noise also large, this is a normal phenomenon, generally after a period of running-in period, the noise significantly reduced or disappear.
① Check if there is oil leakage or vapor leakage phenomenon in the oil pipeline between the fuel dispenser to the tanker. overhaul way is to open the filter cover to see whether there is oil in the low-pressure chamber of the pump, if without oil, then fueling full, appear decline the oil surface, you can determine leakage in the pipeline or at the end of valve.
② Check whether leakage outside of the low pressure cavity of pump, such as filter cover not closed tight, connector of flexible pipe connect lax, return valve loose (with a finger close to the exhaust pipe if inspiration) and so on, there will be a small amount of gas get into result in can not be separated, the solution is to re-install the corresponding seal Department tight, or clean the float or replace return valve components. If after inspection there is still this failure, in the vane pump, the high-pressure pump connecting pipe failures, such as the position movement of flow deflector lead a wrong direction of oil pump, or vent of connecting pipe is too small or blocked, the solution is to re-assemble deflector or replaced. Expand out the vent or replacement of high-pressure connecting pipe (in the vane pumps, the vent pipe is too small or blockage may cause this phenomenon)
③ After all above inspections have not found reason of the malfunction, you can judge the outlet valve failures. Outlet valve is stuck and closed lax, gas and oil together easily through a valve into the flow meter, resulting in oil and gas can not be separated, the solution is discharged out of the oil valve, clean and remove foreign bodies, re-assembly can be.
5.) leakage in exhaust pipe
① Check whether the float in return valve float or not. Mainly manifested return valve can not open, the float component damage, broken levers and so on, which cause increased atmospheric pressure, thus emitting from the exhaust pipe. The solution is to clean oil return valve, repair or replace the float component.
② Check whether the high-pressure connecting pipe out the vent is too large, too large vent make most of the oil directly into the pressure chamber, and thus too late to return to low-pressure chamber and discharged from the exhaust pipe.
③ Check the connecting pipe components in oil pump high-pressure and connections have leakage or no seal (high-pressure cavity square floats seat seal inside of modular gear pump damage) result in too much oil to fill the pressure chamber, too late for return valve to return the oil back to low-pressure cavity, but expel by the exhaust pipe to outside the machine The solution is to replace the gasket or the corresponding components can be.
3. Flow meter malfunction tanker metering Fault
Flow meter malfunction generally divided into two main categories: First, decreased accuracy the second is mechanical failure.
3.1. Common phenomenon of measurement error is not over fueling.
① Large copper set, large piston wear. Solution is to change copper sleeve and piston, or replace new flow meter. Oils contain impurities or other foreign objects into the meter may also damage to the piston.
②Small copper sleeve and adjustment level wear and tear. Solution is to replace the adjustment level assembly or replacement of adjust piston.
③ Mechanical failures and elimination, Shaft system failure, in the form of measuring device can be a continuous row of oil, but with uneven shaft rotation or stop switch. The reasons are:
transmission pin of flexible shaft torque was cut, while have to find out the reasons for Generate additional block and eliminate, and then replace the pin. The holes on Transmission elbow have been worn, elbow drive should be replaced.
Bakelite wheels wear and tear, replace bakelite wheel. In order to prolong the service life, corners on the outside edges of bakelite wheel push rod should be repair smooth and down round, corners promote bakelite round edges with the next piston rod connected to two end-to should repair smooth and down round.
④Piston connecting rod system failures and excluded. The most form of stop fueling for the meter. The reasons are: piston was blocked by foreign body,the solution is to carefully remove the foreign body to avoid damage to copper sleeve, and will repair damaged place smooth.
Due to the long-term idle fuel dispenser, or test machine by water or suction oil with water cause the piston rust or stuck. Solution is: Decomposition flow meter and eliminate rust, and then re-install, immediately test machine by fuel.
Piston and connecting rod loose or the screw of connecting rod end is loosen by vibration when work, leading to death stuck of piston. Solution should be reinstall piston and rod assembly, and check for damage parts, and then re-loaded.
⑤Adjustment pole is invalid. both ends of adjustment screw cap installed wrong, so the adjustment screws and adjustment is not in the same axis and therefore can not adjust, should replace the cover position.