Acrylonitrile Butadiene Styrene
Acrylonitrile Butadiene Styrene (ABS), it is a dark thermoplastic and amorphous polymer. It is a terpolymer (copolymer comprising of three unmistakable monomers) of Acrylonitrile, Butadiene, and Styrene. Together they make an item that is adaptable and light in weight that can be shaped into numerous things that we use in our regular day to day existences.
The benefit of ABS is that an assortment of changes can be had to enhance impact protection, sturdiness, and heat protection. Molding at a high temperature enhances the gleam and heat protection of the item while molding at a low temperature is where the highest impact resistance and strength are obtained.
Polyethylene is a thermoplastic polymer with variable crystalline structure and a huge scope of uses relying upon the type. It is a standout amongst the most adaptable and most famous plastics on the planet since the 1950s when it was produced by German and Italian researchers. The two most regular kinds of this plastic are high-thickness polyethylene (HDPE) and low-thickness polyethylene (LDPE).
The upsides of polyethylene are abnormal amounts of pliability, rigidity, impact protection, protection from dampness, and recyclability. The higher the thickness of the polyethylene material utilized the more grounded, more unbending, and more heat safe the plastic is. The essential employments of polyethylene are plastic sacks, plastic films, compartments including bottles, and geomembranes.
Nylon material is utilized as a part of a vast scope of various applications in view of its electrical properties, sturdiness, wear protection and chemical protection being very noteworthy. Nylon has an abnormal state of strength and is impervious to numerous outer components like scratches, impact, and chemicals. This material produces plastic parts utilized as a part of numerous businesses, for example,
Attire and footwear
High Impact Polystyrene
High Impact Polystyrene (HIPS) is a prevalent and intense plastic that is in the Polystyrene family. Polystyrene is weak and can be more impact safe if joined with different materials. It is made from modifying crystal styrene with rubber which helps to give it many levels of impact resistance. It is low cost, has good dimensional stability and rigidity. There are FDA grades available since it is non-toxic and used as containers for many food goods.
It is exceptionally flammable, yet there are fire resistant and polished evaluations that are generally utilized for injection molding.
This is an extremely regular plastic that is known for its adaptability. PP (polypropylene) is an exceptionally unique plastic and has been intensified for an extensive variety of properties. A few attributes of this plastic are its high liquefying point, high protection toward stress and splitting, magnificent impact quality, and does not break down from responses with water, acids, and cleansers.
PP is ok for use as food holders since it doesn’t filter chemicals into nourishment items. It can be generally found in family unit merchandise, for example, utensils, athletic clothing, area rugs, and car parts, for example, auto batteries.
A brake which uses air as a working fluid is known as pneumatic brake. The system actuated to apply this phenomenon is know as pneumatic brake system.
An pneumatic brake system or a compressed air brake system is a type of friction brake for vehicles in which compressed air pressing on a piston is used to apply the pressure to the brake pad needed to stop the vehicle.
Construction of pneumatic braking system
The simplest air brake system consists of
An air compressor
A brake valve
series of brake chambers at the wheels
A pressure gauge and a safety valve
and an air reservoir.
These are all connected by tubes.
Some air braking systems may have additional components such as
stop light switch
low pressure indicator
An air supply valve to supply air for tyre inflation
A quick release air quickly from the front brake chambers when the brake pedal is released
A limiting valve for limiting the maximum pressure in the front brake chambers and a relay valve to help in quick admission and release of air from the rear brake chambers.
Working of pneumatic braking system
The air compressor operated by the engine forces air at a pressure of 9-10 kscm (kilo standard cubic meters) through the water and oil separator to the air reservoir.
The air pressure in the reservoir is indicated by a pressure gauge.
The reservoir contains enough compressed air for several braking operations. From the reservoir the air is supplied to the brake valve.
As long as brake pedal is not depressed, brake valves stop the passage of air to brake chambers and there is no braking effect.
When the brake pedal is depressed, the brake valves varies its position and compressed air is admitted into the wheel brake chambers.
In the chambers the air acts upon flexible diaphragms, moves them the pushes out the rods connected with the levers of the brake gear cams.
The cams turn and separate the shoes thus braking the wheels.
When the brake pedal is released, the supply of compressed air is cut off from the brake chambers and they are connected to the atmosphere.
The pressure in the chambers drops, the brake shoes are returned to their initial position and the wheels run free.
The brake valve is equipped with a servo mechanism which ensures that the braking force on the shoes is proportional to the force applied to the pedal.
Besides the valve imparts a relative reaction to the movement of the pedal so that the driver can sense the degree of brake application.
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The boiler system comprises a feed-water system, steam system, and fuel system. The feed-water system supplies treated water to the boiler and regulate it automatically to meet the steam demand. Various valves and controls are provided to access for maintenance and monitoring.
The steam system heats and vaporizes the feed water and controls steam produced in the boiler. Steam is directed through a piping system to the application. Throughout the system, steam pressure is regulated using valves and monitored with steam pressure gauges.
The fuel system consists of all equipment used to supply of fuel to generate the necessary heat. The equipment required in the fuel system depends on the type of fuel used in the system.
There are a large number of boiler designs, but boilers can be classified according to the following criteria:
1. According to Relative Passage of water and hot gases:
Water Tube Boiler: A boiler in which the water flows through some small tubes which are surrounded by hot combustion gases, e.g., Babcock and Wilcox, Stirling, Benson boilers, etc.
Fire-tube Boiler: The hot combustion gases pass through the boiler tubes, which are surrounded by water, e.g., Lancashire, Cochran, locomotive boilers, etc.
2. According to Water Circulation Arrangement:
Natural Circulation: Water circulates in the boiler due to density difference of hot and water, e.g., Babcock and Wilcox boilers, Lancashire boilers, Cochran, locomotive boilers, etc.
Forced Circulation: A water pump forces the water along its path, therefore, the steam generation rate increases, Eg: Benson, La Mont, Velox boilers, etc.
3. According to the Use:
Stationary Boiler: These boilers are used for power plants or processes steam in plants.
Portable Boiler: These are small units of mobile and are used for temporary uses at the sites.
Locomotive: These are specially designed boilers. They produce steam to drive railway engines.
Marine Boiler: These are used on ships.
4. According to Position of the Boilers:
Horizontal, inclined or vertical boilers
5. According to the Position of Furnace
Internally fired: The furnace is located inside the shell, e.g., Cochran, Lancashire boilers, etc.
Externally fired: The furnace is located outside the boiler shell, e.g., Babcock and Wilcox, Stirling boilers, etc.
6. According to Pressure of steam generated
Low-pressure boiler: a boiler which produces steam at a pressure of 15-20 bar is called a low-pressure boiler. This steam is used for process heating.
Medium-pressure boiler: It has a working pressure of steam from 20 bars to 80 bars and is used for power generation or combined use of power generation and process heating.
High-pressure boiler: It produces steam at a pressure of more than 80 bars.
Sub-critical boiler: If a boiler produces steam at a pressure which is less than the critical pressure, it is called as a subcritical boiler.
Supercritical boiler: These boilers provide steam at a pressure greater than the critical pressure. These boilers do not have an evaporator and the water directly flashes into steam, and thus they are called once through boilers.
7. According to charge in the furnace.
Supercharged fuel and
Fluidized bed combustion boilers.