compressor

In which speed belt is there a greater speed reduction?

A

Which gear has greater speed?

A

Select all of the compressor auxiliary devices that are basically shell and tube heat exchangers.{multiple selections required}

Aftercooler, Intercooler

Select all of the hazards that may exist around a compressed gas system.{multiple selections required}

Airborne dust and dirt, Hot surfaces, Toxic gases, Excessive noise

The total energy of a flowing gas is a function of its:

All Three Variables

_______ motion is end-to-end movement along the axis of the shaft.

Axial

The pressure rise in a centrifugal compressor is due to __________.

Both Internal and External Effects

In a double-acting compressor, compression occurs at:

Both ends of the compressor.

A dynamic compressor:

Brings the gas molecules closer together

_________ is the amount (volume) of gas the compressor can squeeze at a given pressure. It depends on several factors: cylinder diameter, length of the piston stroke, number of cylinders, and speed.

Capacity

Heavy-duty reciprocating compressor cylinder valves are a form of:

Check valve

Reciprocating compressor has to be started in.

Closed Discharge

An aftercooler is used in a compressor system to remove heat from ________.

Compressed gas

The ratio of the absolute discharge pressure to the absolute suction pressure is referred to as the compressor's ______ ______.

Compression Ratio

The supply of gas to the compressor must be:

Continuous, Dry, Clean

the four factors that determines compressor capacity.

Cylinder diameter, Length of the piston stroke, Number of cylinders, Speed

When the total energy of a gas stays the same, and energy in the form of pressure increases, energy in the form of velocity:

Decreases

Select all of the devices that may be used in a compressed air system to clean or dry the compressed air.{multiple selections required}

Desiccant dryers, Oil separators, Filter

The _______ ______ allow gas to flow out of the cylinder, but prevent it from flowing back in.

Discharge valves

Your tasks to ensure safe operations include:

Each of the task listed.

Select all of the types of drive mechanisms that can be used with compressors.

Electric motors, Gas turbines

Rotary compressors have pistons that rotate inside the cylinders.

False

Throttling a compressor decreases discharge pressure.

False

Unlike mechanical efficiency, volumetric efficiency is always equal to 100.

False

An air compressor typically has some type of _________ in the intake line.

Filtering device

Characteristics commonly used to rate a compressor are

Flow rate, Discharge pressure

____________ are used to direct the gas flow into the impeller eye.

Guide vanes

Select all of the types of protection an operator should wear when working with compressors and compressed gas systems.{multiple selections required}

Hearing protection, Safety glasses or goggles

Which one of the following does not require shutdown of the Reciprocating compressor?

High Oil Filter Differential Pressure

Displacing the gas into a smaller volume __________ the pressure of the gas.

Increases

Within a confined system, when volume decreases, gas pressure:

Increases

The _____ can pivot to regulate the flow of gas into an axial compressor.

Inlet guide vanes

A [_____] is a device commonly used in large compressors to control the amount of gas that is delivered to a receiver.

Inlet valve unloader

Suction valves open when cylinder pressure is

Lower than the suction line pressure.

In a compressor _______ ______ is the percentage of work energy output compared to the amount of energy input.

Mechanical efficiency

The centrifugal tendency of a rotating object is its tendency to:

Move away from the center of rotation

Select the substance that is used to lubricate piston rings in most reciprocating compressors that contain pistons.

Oil

Which of these statements is the reason why the operation of an oil separator is possible?

Oil is heavier than gas.

Reciprocating compressor has to be started with a _____ ______.

Open Discharge

In a reciprocating compressor, the packing rings:

Prevent gas leakage around the piston rod

To reduce pressure fluctuation and Vibration [______] is/are used in Reciprocating compressors.

Pulsation Dampener

Large tanks that store compressed gas are called _________.

Receivers

Gas is displaced with an up-and-down motion in a:

Reciprocating compressor.

The gas traveling through an axial compressor follows a:

Relatively straight path

The _____ are the devices that increase the velocity of a gas inside an axial compressor.

Rotating Blades

One type of system that prevents gas from leaking where a compressor's shaft penetrates the casing is a__________________.

Seal oil system

In an axial compressor, each set of rotating blades followed by stationary blades is typically called a _______.

Stage

The _____ are the devices that decrease the velocity of a gas inside an axial compressor.

Stationary Blades

Axial compressors contain ___________ and ________ blades.

Stator, Rotor

The ______ ______ allow gas to flow into the cylinder but prevent it from flowing back out.

Suction valves

As the compressor reaches operating temperature, which is likely to expand more?

The piston and rod.

Select all of the characteristics that gases in compressed gas systems may have.

They may be toxic, They may be explosive, They may be flammable

A balance drum is generally mounted on the shaft after the last impeller. It is used to balance the total thrust produced by the impellers.

True

Because there is always some energy lost due to heat or friction, mechanical efficiency is always less than 100%

True

Compressed gases produce heat because of molecular friction.

True

In certain environments, compressed air can contribute to conditions that are potentially explosive.

True

Most positive displacement compressors run at low to moderate speeds.

True

While most compressors are capable of running at near 100% capacity, a compressor may be run at a lower capacity to reduce fuel consumption or for other reasons.

True

The single-acting reciprocating compressor has __________ stroke(s) per revolution.

Two

Which of the below statement is/are correct with respect to Critical Speed?

Vibration is very high, Compressor will not be operate at critical speed, Shaft rotational speed at which the rotor bearing support system is in a state of resonance

When the gas leaves the diffuser, it enters the:

Volute

Select all of the choices that are correct when harmful gases are present in a compressed gas system.{multiple selections required}

Wearing a respirator may be required, Their presence is usually noted with a warning sign.

Select the cooling medium that cools a compressor that has metal fins on its casing.

air

[_______] compressors works by spinning gas to increase the speed of the gas flow.

centrifugal

are devices that remove moisture from the compressed gas in a compressed gas system.

demister, desiccant dryer

Using compressed air to clean off your clothing while you are wearing it is perfectly safe.

false

The flow of gas is least controlled in the ____________ impeller

open

A compressor that works by trapping a certain amount of gas and forcing it into a smaller volume is called a(n) [ ] compressor.

positive displacement

A [____] is the primary device that prevents excessive pressure from building up in a compressed gas system.

safety valve

Positive displacement (PD) compressors operate by displacing a ________ volume of gas in each compression cycle.

specific

Compressed air released from a nozzle near a human ear can cause severe damage.

true

One of the most common dangers of compressed air is particles and debris flying back into the face of the operator.

true