General Engineering Flashcards

The sizing of tubing is ____.

Answer: nominal outside diameter

Tubing is typically sized by its nominal outside diameter (OD), unlike pipes which are often sized by nominal inside diameter (ID) or nominal pipe size (NPS). This convention is important for selecting appropriate fittings, clamps, and tools, as the external dimension is critical for connection and installation. The wall thickness then determines the actual inside diameter and pressure rating.

When a refrigeration compressor is short cycled, ______ is meant.

Answer: frequently starting and sopping

Short cycling in a refrigeration compressor refers to the system frequently starting and stopping in rapid succession. This often indicates a problem such as an oversized unit, low refrigerant charge, dirty coils, or a faulty thermostat/pressure switch. Short cycling is detrimental to the compressor's lifespan and energy efficiency, as it causes excessive wear and tear and consumes more power during startup.

The normal usage of the emergency bilge suction valve is ____.

Answer: if the bilges become flooded and they can not be emptied by any other means

The emergency bilge suction valve is a critical safety feature designed to provide a last resort for dewatering the vessel's bilges. It is typically connected to the main circulating pump or another high-capacity pump, allowing rapid removal of large volumes of water in severe flooding situations when the regular bilge pumps are overwhelmed or inoperable. Its use is reserved for emergencies to prevent the vessel from sinking.

The general by-products of oxidation caused by hydraulic il water contamination are ____.

Answer: gums, varnishes, and acids

Water contamination in hydraulic oil, especially when combined with heat and oxygen, significantly accelerates the oil's oxidation process. This oxidation leads to the formation of harmful by-products such as gums, varnishes, and acids. Gums and varnishes can cause sticky residues and blockages, while acids corrode system components, leading to premature wear and system failure.

The _____ must contain a list of the kinds and strengths of steels utilized on a MODU.

Answer: Construction portfolio

The Construction Portfolio for a Mobile Offshore Drilling Unit (MODU) is a comprehensive document that details the unit's structural design and materials. It specifically includes a list of the kinds and strengths of steels used in the MODU's construction. This information is crucial for ensuring structural integrity, compliance with design specifications, and for future maintenance and repair operations.

Which of the following fittings has to be used when installing pipework so that the pump can be removed for maintenance?

Answer: Union

A union is a pipe fitting specifically designed to allow two pipes to be connected or disconnected without disturbing the rest of the piping system. This makes it ideal for installing components like pumps, valves, or filters that may need to be removed for maintenance or replacement. Unions consist of three parts that can be easily separated and reconnected, facilitating quick and efficient servicing.

On a MODU, a continuous waterproof bulkhead can also be a _____.

Answer: structural bulkhead

On a Mobile Offshore Drilling Unit (MODU), a continuous watertight bulkhead often serves a dual purpose as a structural bulkhead. These bulkheads are integral to the vessel's strength and integrity, contributing to its overall structural framework while also providing watertight compartmentalization. This design ensures both stability and safety, especially in offshore environments.

Which of the following best describes a striker or double plate's function?

Answer: Provides landing surface for the sounding bob of a tank sounding tap

A striker plate, also known as a double plate, is a reinforced plate installed at the bottom of a tank, directly beneath a sounding pipe. Its primary function is to provide a durable landing surface for the sounding bob (the weight attached to a sounding tape). This prevents the bob from damaging the tank bottom over time due to repeated impacts during sounding operations, ensuring the tank's integrity.

In the case of a flash type evaporator, a high reading at a salinity cell situated in the loop seal between two stages would suggest ____.

Answer: carryover in the first-stage

In a flash-type evaporator, the loop seal between stages is designed to prevent vapor from bypassing the intended flow path and to maintain pressure differentials. A high salinity reading in this loop seal suggests that brine (high-salinity water) is being carried over from the first stage into subsequent stages. This "carryover" indicates inefficient separation of vapor from the concentrated brine, leading to higher salinity in the distillate or downstream stages.

In terms of MODU construction, the quarters' bulkheads are typically ___.

Answer: non-structural

On a Mobile Offshore Drilling Unit (MODU), the bulkheads within the quarters (accommodation areas) are typically non-structural. This means they are not designed to bear the primary loads of the vessel's hull or superstructure. Their main purpose is to divide interior spaces, provide privacy, and offer some fire and sound insulation, rather than contributing to the unit's overall strength or watertight integrity.

A center gage is used in machine shop practice to verify the angle of ____.

Answer: 60 degree thread cutting tools

A center gage, also known as a thread center gage or screw pitch gage, is a specialized tool used in machine shops. Its primary function is to accurately verify the angle of a 60-degree thread cutting tool before it is used to cut screw threads. This ensures that the cutting tool has the correct profile to produce threads with the standard 60-degree included angle, which is critical for proper thread engagement and strength.