首页/ 题库 / [单选题]Excessive air leakag的答案

Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?()

单选题
2023-03-20 17:06
A、The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow
B、The pump packing gland overheats after short operating periods
C、The motor over-current protective device continually shuts the pump down
D、Pounding noises can be heard at the pump suction chest
查看答案

正确答案
A

试题解析

标签: 船舶辅助机械
相关题目
Chemicals are released into the air. As a result, the atmosphere becomes thicker and ___ more of the Sun's heat.
_____ their hats into the air, the fans of the winning team let out loud shouts of victory.
第二组Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.The passage is mainly about
If a four-stroke/cycle diesel engine is started by injecting air into the cylinder, the pistons receiving the charge of starting air must be()
The air charge leaving an intercooler, or after-cooler of an air compressor can be expected to be ().
Most air conditioning units have () for adjusting the ratio of recirculated fresh airCare must be taken not to reduce the fresh air so that stuffiness or smells arise.
If the sump()were to rise this would indicate water leakage into the oil an d an investigation into the cause must be made.
The air compressor pumps air to the ().
The air compressor pumps air to the().
In the suction stroke air is induced into the cylinder ()In the compression stroke the air is compressed.
If you suspect a diesel engine is misfiring due to air leakage into the fuel system, you should begin looking for the leak at the ()
If you suspect a diesel engine is misfiring due to air leakage into the fuel system, you should begin looking for the leak at the
When the dew point of the outside air is lower than or equal to the dew point of the air in the cargo hold,you should().
The extended aeration process consists of () the liquor either by bubbling air through it or by agitating the surface.
The supercharger takes air out of the surrounding atmosphere and then feeds it to the engine’s ().
The basic process of biological sewage treatment consists of the liquor either by bubbling air through it or by agitating the surface()
While cranking out a quadrantal davit,slippage of the quadrant due to excessive wear or failure of the teeth in the quadrant will cause the().
Combustible gas indicators operate by drawing an air sample into the instrument().
During the suction stroke, the piston is moving ().
Charging is the filling of the engine cylinder with a supply or charge of fresh air () compression.
广告位招租WX:84302438

免费的网站请分享给朋友吧