Equipment pt2

Chapter 6 - Pumps

• Mechanical packing is for pumps in nontoxic, nonflammable, and nonpolluting applications

• Warming up equipment is a typical step when starting a pump

• A centrifugal pump uses an impeller on a rotating shaft to generate pressure and move liquids to the outer casing, then out through the discharge shaft

• Less horsepower is required if the specific gravity of the material is less than 1.0

• Radial loads are perpendicular to the shaft

• A seal system with a primary and backup seal is a tandem seal

• Cavitation can occur if the pressure on the eye of a pump impeller falls below the vapor pressure of the liquid being pumped

• Density and specific gravity affect pump selection

• All of the following are contained in a manufacturer's supply performance pump curve for centrifugal pumps: head, flow rate, and efficiency

• Excess vibration in a pump can cause mechanical failure

• Canned pumps can be used with liquids that are difficult to seal

• All of the above are applications for pumps: filling tanks, emptying trenches, and supplying water to boilers

• Cavitation can cause vibration

• Cavitation, overheating, and mechanical failure can result from abnormal pump speed

• Closing the suction and discharge valves is a typical step in a pump shutdown procedure

• The amount of head is determined in a pump by the height of the liquid

• Suction pluggage can cause cavitation

• Suction Static Head is the vertical distance between the centerline of a pump and the surface of the liquid on the suction side of the pump

• Dynamic pumps utilize impellers to generate a centrifugal force

• When monitoring and maintaining pumps, technicians should monitor oil levels and check suction pressure across strainers/screens

• Over pressurization can occur if valves beyond the pump are incorrectly closed or blocked

Compressors

• A compressor with a suction pressure of 800 psiA and a discharge pressure of 1600 psiA has a compression ratio of 2

• The auxiliary system that circulates and cools the sealing and lubricating oil is a lubrication system

• Process technicians can identify a problem trend by checking and recording pressures, temperatures, and flow rates

• All of the following should be considered when selecting a type of compressor: Type of liquid being compressed, Discharge pressure, Viscosity

• Process technicians should look for oil levels, vibration monitors and flow rates when doing operation and maintenance on compressors

• Flow rate is expressed in cubic feet per minute (cfm)

• Severe compressor vibration can be an indicator of surging

• Bearings and seals become hotter when gases are compressed

• Reciprocating compressors use a back-and-forth or up-and-down motion to pressurize gas

• Leaking compression valves can cause loss of capacity in a reciprocating compressor

• A labyrinth seal is designed to restrict flow by requiring fluid to pass through a series of ridges and intricate paths

• A dynamic compressor may stall when the volume of gas entering it drops below a critical flow rate

• Exposure to hazardous materials is an equipment hazard associated with compressors

• Rotary compressors are used in applications where operating conditions (flow/pressure) vary greatly

• All of the above are personal safety hazards associated with compressors: Skin burns, Chemical exposure, Excessive noise levels

• A loss of cooling in a compressor can cause overheating

• A variable speed drive is an anti-surge device that controls the discharge pressure

• Centrifugal compressors allow gas to flow from the inlet, located near the suction eye, to the outer tip of the impeller blade in dynamic compressors

• Discharging harmful gas into the air is an environmental hazard associated with compressors

• Dynamic compressors require less maintenance, making them more common than positive displacement compressors

• A Centrifugal compressor is used for continuous-duty applications that require high volumes but relatively low pressures

Chapter 8 - Turbines

• Burns from exposure to heat or steam can be caused by uninsulated equipment and piping

• A Kaplan turbine is a reactive turbine

• Unblocking the high-pressure steam is a typical step in the start-up procedure for a noncondensing steam turbine

• A nozzle is designed to increase the velocity of steam

• High-quality oil should be used to reduce the risk of parts fusing together

• Loss of lubrication can be caused by oil pump failure

• Impingement occurs when the steam quality decreases to the point that steam condensate exists in the turbine

• All of the above should be monitored by a process technician: Oil levels, Safety interlocks and devices, Inlet and exhaust steam temperatures

• A reactive design is typically used for lower-pressure fluids

• Single-stage steam turbine is a device that contains one set of blades

• Fouling is caused by mineral deposits from the steam

• Having water droplets in the incoming steam of a steam turbine can cause severe vibration problems

• Steam turbines are free from sparks, which is an advantage of them over electrical equipment

• Gas is one of the most common types of turbines

• The casing is the component of a steam turbine that houses the internal components

• Reactive turbines use Newton's third law of motion

• Switching to the spare turbine is a typical step in the shutdown procedure for a steam turbine

• Heat rejection is the fourth stage of the Brayton cycle

• Compression is the first stage of the Brayton cycle

• All of the above are major components of combustion gas turbines: Air inlet, Axial air compressor, Combustion chamber

• A condensing steam turbine is a device in which exhaust steam is condensed in a surface condenser, and the condensate is recycled to the boiler

Chapter 9 - Motors

• The crankshaft converts the piston's up-and-down or forward-and-backward motion into rotational motion in an internal combustion engine

• Electric Shock is the most common hazard associated with normal and abnormal operation of motors.

• All of the above are electromagnetic principles that electric motors operate on: Like magnetic poles repel each other, Electric current generates a magnetic field, The direction of the electrical current determines the magnetic polarity

• Three-phase electricity motor are most used in process facilities

• Steam turbines require a boiler and all its auxiliaries to produce steam, it's a disadvantage of them

• Synchronous motors run at a fixed speed that is synchronized with the supply of electricity

• Monitoring lubrication is a role of a process technician with regard to the operation and maintenance of motors

• Variable speed motors allow for the adjustment of the motor's rotation speed

• All of the above are benefits of motor control centers: They protect against short circuits, They protect against overloading, They protect against overspeed

• Frame is a structure that holds the internal components of a motor and its motor mounts

• A process technician is the key person for detecting an abnormal condition in an engine

• A motor is a mechanical driver that converts electrical energy into useful mechanical work

Chapter 10 - Power Transmissions

• High temperatures can be caused by a locked rotor

• A Camshaft is a driven shaft fitted with rotating wheels of irregular shape that open and close the valves in an engine

• AC motors are most commonly used where variable speed or high-torque applications are needed

• All of the above are reasons why electric motors are often preferred: Reliability, Ease of use, Low maintenance cost

• Class III is the class of electrical hazard classifications used to identify fibers that are easily ignitable

• No load occurs when the motor is not using torque

• B is the group designation used for a Class I electrical hazard

• The stator is the stationary part of the motor where alternating current, supplied to the motor, flows, creating a magnetic field using magnets and coiled wire

• All of the above are critical as part of a good lubrication program: On-site inspection, Off-site analysis, Routine sampling

• Couplings, Belts and Sprockets are mechanical devices used to connect and transfer rotational energy from the shaft of the driver to the shaft of the driven equipment.

• Flexible is what coupling is used the most frequently in general power transmission service.

• Polarity is Switched repeatedly is what is a characteristic of AC power.

• Imp. is a unit of measure of the electrical current flow in an electrical circuit.

• High Vibration can be electrical problems due to motor misalignment.

• high temps is the result of a loss of cooling airflow.

• Batteries is a DC electric power source.

• Belts are flexible bands to transmit rotational energy.

• Light-duty belts are used with smaller drive pulleys.

• Couplings are designed to be the 'weak link' between the driver, gearbox, or machinery train

• Ball bearings are used in smaller machinery and at low speeds

• Gravity feed lubricants are called bottle oiler

• Interlock protection is there to keep large, single-train, rotating equipment from sustaining serious damage when upset conditions or component failures occur

• Forced feed lubricants are found in larger machinery

• An improper start-up can cause sudden surges that can shorten the life of rotating equipment

• Roller Bearings are used in moderate-pressure applications and at low speeds.

• ALL of those listed are tasks for maintaining power transmissions: Check oil levels, Check the grease supply, Switch oil filters.

• Oil mist type lubricant uses a oil distribution system.

• Watts consumes a current with the force of voltage.

• Transformer takes electricity and modifies voltage levels.

• Worm gears would be used in low power applications.

• Spur gears are used in high power applications

• Worm gears obtain large speed reductions between non-intersecting shafts

• Step-down transformers step down voltage for residential consumers

• 110 voltage is used for indoor lighting

• Chains have minimal stretching