_______can cause oil flow from water outlet of the oil purifier.A.Oil inlet valve opening

____ can not cause oil flow from water outlet of self-cleaning separator.

A.Oil temperature too high

B.Diameter of gravity disc too large

C.Oil temperature too low

D.High level tank out of water

____ can cause oil flow from water outlet of a separator.

A.Oil inlet valve opening too quickly

B.Oil temperature too high

C.Diameter of gravity disc too small

D.Viscosity of oil too low

____ can cause oil flow from sludge outlet of self cleaning separator.

A.Too much sludge accumulated in separator bowl

B.Diameter of gravity disc too large

C.High level tank lack of water

D.Oil input too rapidly

Leaking oil seals on a diesel engine turbocharger can cause

A.the engine to run after the fuel has been secured

B.the engine to over-speed

C.a fire

D.all of the above

A dirty intercooler on an air compressor will cause _____.

A.damage to the un-loader operating diaphragm

B.an increase in current flow to the motor

C.high pressure in the receiver and filter

D.an excessive consumption of crankcase oil

A.Shortage of refrigerant oil

B.Slight shortage of refrigerant

C.Excessive condenser cooling water flow

D.Faulty expansion valve

听力原文： Unless measures are taken at once, there is a good chance that all the oceans of the world will be heavily polluted by the year 2000. How could this possibly happen？

We have already seen that people allow all kinds of waste products to flow into the sea. It is almost impossible to measure how much sewage and industrial waste end up in our oceans. And [low about oil pollution in the oceans？ It is illegal to discharge oil into the sea close to the coast, but when a ship is many miles out to sea there are no such restrictions. Sometimes there is a ship collision, and our beaches are covered with oil. But collisions are not the only cause of oil pollution, not even the main cause. Much more oil is discharged at sea when the oil tanks are cleaned out.

Estimates of the amount of oil discharged into the sea vary quite a lot, but the lowest figure for oil discharged into European waters alone is about 200,000 tons every year. Some people say that the figure could be ten times higher.

It is not only our beaches that are polluted by oil, among other things, some fish in the sea now contain great amounts of poisonous substances. Next time you eat fish, how can you be sure that they are free from oil pollution？ It is really quite a problem.

(30)

A．Sewage and industrial waste.

B．Oil pollution on the beach.

C．Oil discharged at sea when people cleaning oil tanks.

D．The oil that leaks out after ship collisions.

A.seal water supply be cut off

B.make up water supply be cut off

C.oil outlet valve closed or not open sufficiently

D.the flow rate of oily water is too much

第二组

The only attention that heat exchanger should require is to ensure that the heat transfer surfaces remain substantially clean and the flow passages generally clear of obstruction. Indication that undue fouling is occurring is given by a progressive increase in the temperature difference between the two fluids, over a period of time, usually accompanied by a noticeable rise in pressure loss at a given flow.

Fouling on the sea-water side is the most usual cause of deterioration in performance. The method of cleaning the sea water-side surfaces depends on the type of heat exchanger. With shell-and-tube heat exchangers, the removal of the header covers or, m the case of the smaller heat exchangers, the headers themselves, will provide access to the tubes. Obstructions, dirt, scale etc., can then be removed, using the tools provided by the heat exchanger manufacturer. Flushing through with fresh water is recommended before a heat exchanger is returned to service. In some applications, such as piston oil cooling, progressive fouling may take place on the outside of the tubes. Most manufactures recommend a chemical flushing pr6cess to remove this in situ~ without dismantling the heat exchanger.

Plate heat exchangers may be cleaned by unclamping the stack of plates and mechanically cleaning the surface of each plate as recommended by the manufacturers. The plate seals may require replacement from time to time and here the manufacturers&39; instructions should be closely followed

By which of the following indication, can we conclude that the lube oil-sea water heat exchanger is unduly fouled？

A.the heat exchanger lube oil inlet temperature lowering

B.the heat exchanger sea-water outlet pressure rise

C.the heat exchanger temperature difference between lube oil and sea water increasing

D.the heat exchanger pressure difference between sea water inlet and outlet decreasing

A.hemorrhoids

B.bloodletting

C.hemophilia

D.bleeding