Evaluación del desarrollo y ajuste psicológico de los hijos e hijas

The coalescing type of separator must be used if the water in the fuel is broken into such small particles that they make the fuel cloudy.

A coalescing-type separator will separate all water from fuel. It can be put anywhere in the fuel line, such as next to the components that need

4

SUGGESTED ARRANGEMENT FOR WATER AND SEDIMENT TRAP

1. Fuel inlet 2. Inlet baffle 3. Hand hole and cover 4. Fuel Outlet 5. Baffles

6. Openings at bottom of baffles for drainage 7. Drain Opening

8. Air bleed plug

Sediment Trap Capacity

Note: Suggested minimum size of trap Fuel Cons. Tank Cap.

25 5000

= +

the most protection from water. The elements are composed of two-stage paper media that are replaceable. You can tell the element is plugged when there is a lack of fuel pressure.

Catalytic Fines

Catalytic Fines are small, hard particles which originate at the refinery.

They are usually composed of aluminum and silicon particles and can cause very rapid abrasive wear.

Engine Effects

Catalytic Fines will severely damage injection pumps, injectors, piston rings and cylinder liners.

Proper fuel treatment methods (centrifuging and filtration) will remove these particles.

Volatile Fuel Components

Certain liquids are present in fuels in a vapor or gaseous state. This can cause an interruption of fuel supply to the fuel pump.

Lighter fuels and crude oils will have greater tendency to this problem than heavier fuels.

An air eliminator, or vapor trap, can be used to minimize the effect of interrupted fuel supply due to vapor lock.

The vapors and gases, thus separated are combustible and must be disposed of according to safe venting practice.

Simple venting to atmosphere is not adequate, since some of the vapors and gases may be heavier than air and tend to collect or pool in low spots, forming a severe safety hazard.

Asphaltenes

Asphaltenes are components of asphalt that are insoluble in petroleum naphtha and hot heptanes but are soluble in carbon disulphide and benzene. They are hard and brittle and are made up of long molecules with high molecular weight. In high concentrations, asphaltenes can cause filter plugging. They often contain heavy metals such as nickel, iron and vanadium. Asphaltenes are not present in distillate fuels.

Microorganisms in Fuel

Extensive filtering of the fuel after using the biocide is required to elim-inate engine-mounted filter plugging.

Steps to minimize problems with bacterial growth:

• Avoid long fuel storage periods.

• Drain water from fuel tanks daily.

• Purchase fuel from reliable sources.

• Dose all fuel inventory with biocide at the first sign of microorganism contamination.

Air

Air can be dissolved in fuel, and it can also be pulled into the fuel lines by a leak on the suction side of the fuel transfer pump.

Engine Effects

Air in the fuel will cause starting problems, missing, low power and smoke problems. Air can also cause excessive white smoke in some engines.

Reducing the effects of air in the fuel system.

Remove air by bleeding the fuel system. Check for dissolved air in fuel with a 2P8278 Fuel Flow Tube. Correct suction piping leaks.

Filters

Primary Fuel Filter Element Specification

The primary fuel filters elements should have the following properties:

Mesh Size– 70  80 strands per in. (32  28 strands per cm) Element– Monel wire cloth material or equivalent

Element Area– 100 in²(645 cm²) or greater

Opening Size– 0.007 in.  0.0088 in. (0.1778 mm  0.2235 mm) Duplex Fuel Filters

Many Caterpillar Engines can be equipped with duplex fuel filters.

These filters may be serviced (change elements), without shutting off the engine. There are two types: the symmetrical type – which has two identical filter sets and the main-auxiliary type – which has a main fil-ter set and a smaller capacity auxiliary filfil-ter set. A special valve con-nects the two sets of filters in each type. The valve routes the fuel to be filtered through either or both sets of filters.

Both filter sets can be used simultaneously to extend running time in an emergency.

Filter Micron Ratings

Caterpillar does not specify filter or filter paper by micron rating.

Caterpillar specifies actual filter capability, rupture strength, the capac-ity for holding dirt, flow resistance, filter area, etc.

Micron ratings are easily confused for the following reasons:

• The test for micron ratings is not repeatable at different labs. One manufacturer may give a rating of 0.00039 in. (10 microns), another at 0.000079 in. (2 microns), and a third may rate a particular filter media (paper) at 0.00059 in. (15 microns).

Micron ratings are overemphasized; a 10 micron filter will not always stop a 10 micron particle. Many reputable filter manufacturing firms are drifting away from micron ratings to more conclusive tests.

Smaller micron ratings are not necessarily better.

If all other factors (area) were equal, a smaller micron number media (paper) has a severe drawback: less capacity before plugging, needs to be replaced more often. The size of the pores in the paper needs to be balanced against the costs of the filter replacement.

Common questions are:

• What is the maximum particle size which can pass through Caterpillar filters?

• What is the difference between nominal size and absolute size filters?

For example: A nominal 10 micron filter media (paper) will pass some particles up to about 50 microns in size. Theoretically, an absolute rat-ing of 10 microns will stop all particles larger than 10 microns. In fact, filters with absolute micron ratings of 10 will pass some particles larger than 10 microns due to the irregularity of the paper weave. New filters may pass larger particles than they will after only a few hours of use.

As a general rule, Caterpillar fuel filter media (paper) is about 3 microns nominal, 20 microns absolute. Oil filter media (paper) is about 10 microns nominal, 50 microns absolute. These are approximate values only.

Filters are not effectively compared on the basis of micron rating alone.

Evaluate filters on the basis of their ability to collect foreign material as a whole.