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Photos from Mechanical Engineering Blog's post 16/03/2024
16/03/2024

Why is NPSH required to increase as the pump flow rate increases❓

👉Net Positive Suction Head is defined as the following:

NPSH= Absolute pressure above the fluid in the tank + Head of the fluid available above/below the pump centerline + Velocity of fluid in the suction pipe - Frictional head loss in the suction pipe - Vapour Pressure head of the liquid at the ambient temperature (Assuming isothermal process)

If you read the above equation carefully, NPSH is the head required to make the fluid flow to the impeller. The two negative terms on the RHS of the above equation re**rd the flow of liquid to the pump impeller.

Now let's consider the effect of change of each of the terms on the RHS on the NPSH.

Absolute pressure above the fluid in the tank: Normally, the tank is at atmospheric pressure. If by some means we increase the pressure above the fluid in the tank to above atmospheric, the fluid flow to the pump will be assisted by the increased pressure and vice versa.
Head of the fluid available above/ below the pump centerline: If the pump is installed under positive head, higher the head of the fluid, more will be the head available at the impeller. If the pump is installed under negative head, i.e. the pump is mounted above the fluid to be pumped, the suction head will increase (negative) as the distance of the pump above the fluid surface increases.

Velocity of fluid in the suction pipe: If the pump is installed under positive head, the velocity in the suction pipe increases with increase in the head and vice versa.
Frictional head loss in the suction pipe: This will increase as the flow velocity and the pipe length increase but reduces as the pipe diameter increases.
(Assuming constant friction factor) This is the reason for the larger diameter of the suction pipe than the delivery pipe for most centrifugal pumps.

Vapour pressure head: The vapour pressure of a pure substance is constant at a particular temperature. For example, the vapour pressure of water at 100 degree centigrade is 1 atm. As the pressure is reduced the boiling temperature ( Vapour pressure temperature) also reduces. So it is undesirable to have restrictions in the suction pipe of a pump which increase the pressure losses ultimately leading to ev***ration of the liquid at the ambient temperature.

For example, water may boil even at 25 degree centigrade if the pressure of water is reduced below its v***r pressure at this temperature. This term is given a negative sign in the above equation since the pressure at or below the v***r pressure of the fluid to be pumped will cause a vapour lock and reduce the volumetric efficiency of the pump. The result of this is CAVITATION.

The above discussion proves that NPSH is the head required to make the fluid flow to the impeller. Hence if the NPSH is increased, the fluid flow to the pump impeller will increase resulting in increased flow rate.

14/02/2024

‼️Ohm's Law & Power‼️

05/02/2024
21/01/2024

HEAT EXCHANGER TYPES & APPLICATIONS

A heat exchanger allows the heat from a fluid (liquid or gas) to pass through a second fluid without the two ever coming into direct contact with each other.

For example, a heating furnace burns natural gas that is carried over water by pipes. If the gas and the water came into direct contact, the heat exchange would stop and the water would never warm up.

Even though all heat exchangers perform the same function, there are different types that have varied applications. Learning about these different heat exchangers will help you determine what the right equipment is for your business.

Let’s take a look at the 4 types of heat exchangers and their applications below:

1. Double Tube Heat Exchangers:

Double tube heat exchangers use what is known as a tube within a tube structure. There are two pipes where one is built inside the other. Just like the example above, one fluid flows through the inner pipe while the second fluid flows around the first fluid in the outer pipe.

This type of heat exchanger is known for being the most basic and affordable of all. Its size makes it ideal for tight spaces, allowing for some extra flexibility in the layout of the manufacturing process.

2. Shell and Tube Heat Exchangers:

Out of all the types of heat exchangers, shell and tube heat exchangers are the most versatile. A shell and tube heat exchanger is designed with a number of tubes placed inside a cylindrical shell.

The popular design of this type of heat exchanger allows for a wide range of pressures and temperatures. If you need to cool or heat a large amount of fluids or gases, the application of the shell and tube heat exchanger is an option to consider.
While smaller in size compared to some of the other types, a shell and tube heat exchanger can be easily broken-down, making cleaning and repairs easy.

3. Tube in Tube Heat Exchangers:

Similar to the other types of heat exchangers, a tube in tube heat exchanger is comprised of t

04/11/2023

Do you know What is Cascade Control?

In a cascade control arrangement, there are two (or more) controllers of which one controller’s output drives the set point of another controller. For example: a level controller driving the set point of a flow controller to keep the level at its set point. The flow controller, in turn, drives a control valve to match the flow with the set point the level controller is requesting.

The controller driving the set point (the level controller in the example above) is called the primary, outer, or master controller. The controller receiving the set point (flow controller in the example) is called the secondary, inner or slave controller.

Cascade control can improve control system performance over single-loop control whenever either: (1) Disturbances affect a measurable intermediate or secondary process output that directly affects the primary process output that we wish to control; or (2) the gain of the secondary process, including the actuator, is nonlinear. In the first case, a cascade control system can limit the effect of the disturbances entering the secondary variable on the primary output. In the second case, a cascade control system can limit the effect of actuator or secondary process gain variations on the control system performance. Such gain variations usually arise from changes in operating point due to setpoint changes or sustained disturbances.

08/10/2023

INDUSTRIAL STORAGE TANKS 🛢

Industrial storage tanks are containers used for storage of gas, oil, water, and petrochemical products, employed for industrial uses. Industrial storage tanks come in different sizes and shapes.

They can be underground, horizontal, and vertical, and be made from concrete, stone, fiberglass, steel or plastic.

Industrial storage tanks can be categorized into several types based on the substance they hold and some other factors.

Types of Industrial Oil Storage Tanks

Floating Roof Tank

As the name suggests, the floating roof tank consists of a floating roof which falls or rises according to the level of oil in the tank. To prevent the build-up of v***r inside the tank, the floating roof in this type of tanks has been incorporated as a safety feature.

Fixed Roof Tank

In the fixed roof tank, the oil stored is not exposed. This tank type is employed for holding oil products in lower volumes than in case of tanks having floating roofs.

Bunded Tank

Bunded tanks are enclosed by one more tank or have a containment d**e surrounding the tank. The containment d**e or outer tank acts as a catch system for preventing leakages, oil spills, or other types of oil contamination from being spread to the surroundings.

Single Skin & Double Skin Tanks

Single skin tank has one layer and double skin tank has two layers of plastic or steel. Double skin tanks are also known as twin-walled tanks.

Open Top Tank

This type of industrial oil storage tank was used earlier. Its use is limited now due to ev***ration losses as well as the risk of oil catching fire.

27/09/2023

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Catalytic Reforming ✅✅

Catalytic reforming is a chemical process used to convert petroleum refinery naphthas distilled from crude oil (typically having low octane ratings) into high-octane liquid products called reformates, which are premium blending stocks for high-octane gasoline. The process converts low-octane linear hydrocarbons (paraffins) into branched alkanes (isoparaffins) and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons

04/03/2023

What Is Bitumen?

The term bitumen refers to a substance produced through the distillation of crude oil. Bitumen is known for its waterproofing and adhesive properties and is commonly used in the construction industry, notably for roads and highways. Production occurs through distillation, which removes lighter crude oil components like gasoline and diesel, leaving the heavier bitumen behind. Deposits can also occur naturally at the bottom of ancient lakes, where prehistoric organisms have decayed and been subjected to heat and pressure.

Bitumen is a byproduct of crude oil. it is composed of complex hydrocarbons and contains elements like calcium, iron, sulfur, and oxygen. The quality of material and ease of production depends on the source and type of crude oil from which it is derived. It was first used for its natural adhesive and waterproofing characteristics, helping to bind building materials together, as well as to line ship bottoms.
Bitumen can deform permanently under heavy loads. Continued stress on the material can result in cracking. It oxidizes, which can leave the asphalt brittle. The way its shape is affected depends on a few things, including the composition of the asphalt mixture and the ambient temperature.
Bitumen Uses

The product has several modern uses. It's generally meant for industrial use and is commonly found in road paving. The majority of U.S. roads are made of either bitumen or a combination of bitumen and aggregates, such as concrete.

Another key use for bitumen is waterproofing. For instance, it was commonly used to waterproof boats and other marine vessels, as well as the sides of buildings. It was used in ancient times as mortar in building construction.

Along with being used as a waterproofing agent and acting as an adhesive, engineers who replace asphalt roads can reuse the material for other road projects. Bitumen is also commonly used by companies that create and manufacture roofing products.

Another early use of bitumen was in photography and medicine. When bitumen was applied to plates and exposed to light, early photographers were able to produce static black and white images. This process, though, was long and drawn out. And some cultures—notably Persian—used bitumen to treat certain illnesses, such as gastrointestinal and bone disorders.

Photos from Mechanical Engineering Blog's post 02/03/2023

Pump-Motor Shaft Alignment Procedure 👍🏻

12/02/2023

Diagram of a Turbocharger✅

Photos from Mechanical Engineering Blog's post 12/02/2023

Hot 🔥Tapping Process ✅✅

Photos from Mechanical Engineering Blog's post 11/02/2023

Autocad Important ✅✅

Photos from Mechanical Engineering Blog's post 11/02/2023

Types of Flanges used in Piping System ✅✅

Photos from Mechanical Engineering Blog's post 11/02/2023

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Hydrostatic (Hydro) Testing is a process where components such as piping systems, gas cylinders, boilers, and pressure vessels are tested for strength and leaks. Hydro tests are often required after shutdowns and repairs in order to validate that equipment will operate under desired conditions once returned to service.

Photos from Mechanical Engineering Blog's post 07/02/2023

Steam Traps ✅✅

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