COOLING TOWERS

          The primary task of a cooling tower is to reject heat into the atmosphere. It works on the principle of evaporation. In this process the sensible heat of hot water is converted to latent heat of vaporization.

Cooling tower types:

          Cooling towers falls into two main categories: (1) Natural Draft and (2) Mechanical draft.

Difference between Natural Draft and Forced Draft Cooling towers

Natural Draft Towers:

          Natural draft towers use very large concrete chimney to introduce air through the media. Due to the large size of these towers, they are generally used for water flow rates above 45,000 m3/hr. These types of towers are used only by utility power plants.

Mechanical Draft Towers:

          Mechanical draft towers utilize fans to force or suck air through circulated water. The water falls downwards over fill surfaces which help increase the contact time between the water and the air - this helps maximize heat transfer between the two. Cooling rates of Mechanical Draft Towers depends upon their fan diameter and speed of operation.

Mechanical draft cooling towers:

          Mechanical draft towers are available in the following airflow arrangements:

Counter flow induced draft.

Counter flow forced draft.

Cross flow induced draft.

Components of cooling towers:

The basic components of evoparative tower are: Frame and Casing, Fill, Cold water basin, Drift eliminator, Air inlet, Louvers, Nozzles, and Fans.

Components of Different types of cooling towers

Credits: Slideshare.net

                Thermal control magazine

                 Kooldrop.com

                 

SHIMS

Image source: Credits : Wikipedia

5S CONCEPT IN INDUSTRIES

Image Credits : GOOGLE

          5S is a regular systematic form of visual management, using everything from floor tape to operation manuals. It not only simply focus on visual order, authentication, hygiene or organisation; It is also about increasing efficiency, profitability, service and safety. 5S is a unique idea and framework that emphasizes the utilisation of a specific mindset and instruments to create efficiency and esteem. The principles underlying a 5S program initially seem to be simple and obvious common sense. However, once implemented in a disciplinary manner, the above benefits will occur.

          This system focuses on keeping everything where it works and keeping the workplace clean, making it easier for people to do their jobs without wasting time, without confusion and without injuries. It involves observing, assessing everything present in a space, collaborating, and searching for waste and also furthermore includes the practice of removing waste, keeping this cycle going organise, clean, repeat.

5S include five Japanese terms that everyone begin with the letter "S".

Credits: Google

What Does 5S Stand For?

          5S, generally stated as 5s or Five S. 5S came from Japanese terms. These Japanese words used to describe the phases of the 5S system of visual management. Each term begins with an S. In Japanese, the 5S's are Seiri, Seiton, Seiso, Seiketsu, and Shitsuke. In English, the 5S's are usually translated as Sort, Set in order, Shine, Standardize, and Sustain.

The Five key practices are as described below:

1) JAPANESE TERM -- Seiri

    ENGLISH TERM    -- Sort

          It involves going through all the tools, materials, equipment etc., keeping solely the essential items needed for the full work.
Some questions that have to raise our self at this stage are:
--> What is the utilisation of this equipment or item?
--> When was the last time this item was used?
--> However typically it is used?
--> Who used it?
--> Do this item really essential to be here?
          This action passes through all subjects in a workplace and work piece to determine the value of each item and ends with the need and removal. Everything that has not been used to complete the work process ought to leave the work area.   

2) JAPANESE TERM -- Seiton

    ENGLISH TERM    -- Set in order

          Once the extra items are removed it is easier to see and identify what is what. Make sure that all items are sorted out and each item has an assigned location. Organise all the remaining items in a logical way and felicitate the work to make the workers complete.  This often involves:

• Which people (or workstations) use which items?
• At what point those items are used?
• what items are often used?
• Should things be sorted by type?
• Where would it not be most obvious to place items?
• Do some appointments on unnecessary movements?
• Need more storage containers to handle things?

 3) JAPANESE TERM -- Seiso

      ENGLISH TERM    -- Shine

          The shine stage of 5S focuses on proactive efforts to keep workplace areas clean and orderly. This means cleaning and maintaining the recently sorted-out workspace. It involves simple and routine tasks such as sweeping, moping, wiping down surfaces, putting tools and materials away etc., In addition to basic cleaning, performing regular maintenance of machinery, tools and other equipment.

 4) JAPANESE TERM -- Seiketsu

      ENGLISH TERM    -- Standardize
          After completing first three steps of 5S, things should look pretty good. All the unnecessary things is gone, everything is maintained, spaces are cleaned, and equipment is in good working condition.
          In this stage create a set of standards for both organization and processes. Fundamentally, this is where you take the first three S's and make rules for how and when these tasks will be performed. These standards can involve regular tasks, creating schedules, charts, lists, and posts instructions so these exercises turned out to be standard.

5) JAPANESE TERM -- Shitsuke

      ENGLISH TERM    -- Sustain
          Sustain refers to the process of keeping 5S running smoothly, yet in addition of keeping everyone in the association included and involved. Sustain new practices and conduct audits to maintain discipline. This suggests the previous four S's must be continued over time. First of all managers need to participate to give motivation to employees, and make the employees to follow these steps on the manufacturing floor, or in the office. Sustain is about making 5S a long-term program, not only just an event or here and now venture (short-term project). Ideally, 5S turns into a part of an organisation's culture and when 5S is sustained after some time, that's when businesses will begin to see persistent positive outcomes.

6) SAFETY -- THE 6th S
          Some companies prefer to include a sixth S in their 5S program i.e., Safety. At that point when safety is included, this framework is often called as 6S. The safety step involves focusing on what can be done to eliminate risks in work processes by arranging things in certain ways.
          Some industries believes Safety a result of performing the other 5S's appropriately, and thus say 6S isn't necessary. They think whether workplace is properly organised and cleaned and uses helpful visual safety cues, a separate safety step is senseless.
          Neither approach to safety is right or wrong, but however a business needs to approach safety, it ought to bear in mind that paying attention to safety is vital.

Credits: wikipedia

                https://www.5stoday.com/

DIFFERENT TYPES OF WELDING RODS EXPLAINED

What is Welding ?

          "Welding is the process of fusing (Joining) two pieces of metals (also called Workpieces) together". This is practiced by passing electric current from the welding electrode to the workpiece that makes an electric arc.

          The electric are heats and dissolves the two metals together, which thus, fuses the two metals together resulting more grounded bond. The welding machine supplies the electric flow which is either in the form of alternating current (AC) or direct current (DC).

What is a Welding rod ?

          Welding electrode, commonly referred to as a "Welding rod", is a component of a flux-coated metal wire that acts as a filler when utilized in a welding process called "Shield metal arc welding" or "SMAW".

          In the SMAW process, also commonly mentioned as "stick welding", the welding rod (a.k.a "stick" electrode) melts along with the workpiece, acting as Filler. Because of this action, the welding rod is generally categorized as consumable electrode type.

          In TIG welding, the welding rod doesn't melt, so they are categorized as non-consumable electrodes.

          The welding rod is primarily consisting of a metal wire (or) rod (Steel, Aluminium, Bronze) and its outer flux coating. This metal rod melts and becomes part of the weld when the electric arc is created. This metal rod should generally be the same (or) identical material to the workpiece. However, there are welding cases that the welding rod and workpiece are of dissimilar materials.

          The flux coating is the material that decomposes into a shielding gas during the welding process. The gas shielding protects the weld pool (the molten steel) rather than being contaminated by the atmospheric gas. A part of these flux coating likewise turns into a kind of plaque known as Slag, which protects the weld as it cools.

What's in the name of a Welding rod ?

          The American Welding Society (AWS) has designed an Alpha-Numeric system for naming welding rods.

          If we would take E 7018 welding rod as example, we would notice that there is one Alfa digit (E) and four numerical digits (7018). For starters, the letter 'E' stands for 'Electrode'. Take note of this to make sure you are using the right kit for the job!
          The first two numbers of 7018 correspond to the tensile strength or the stress bearing capasity of the weld bead. Therefore, in the case of 7018 welding rod, the weld bead can withstand 70,000 lbs. per square inch. For this reason, the higher the first two numbers, the greater the strength of the electrode (1 lbs = .45 kgs). 

          The third digit, on the other hand, represents the number of positions in which the welding rod can be used. It is important to remember that there are four primary welding positions, namely the Flat, Horizontal, Vertical, and Overhead positions. A number "1" on the third digit (7018), therefore, basically means that it can be used for all four welding positions.
          The last digit should be read in conjunction with the second-to-last number: together,however, refers to the coatings used on the electrodes. Electrodes are usually coated with varying chemicals to protect the joints while welding. These chemical coating can determine the amount of current applied in the welding process. Moreover, the welding power supply varies depending on the amount of current required in the welding process. The power supply is as simple as a car battery (or) as advanced as a high-frequency inverter that uses IGBT technology and can be controlled by a computer.
          See the below table for full list of stick electrode classification based on coatings and the necessary welding currents based on the last two digits of the classification code.

Electrode Table
ELECTRODE DIAMETER (THICKNESS)	AMP RANGE	PLATE
1/16"	20 - 40	UP TO 3/16"
3/32"	40 - 125	UP TO 1/4"
1/8”	75 - 185	OVER 1/8"
5/32"	105 - 250	OVER 1/4"
3/16"	140 - 305	OVER 3/8"
1/4"	210 - 430	OVER 3/8"
5/16"	275 - 450	OVER 1/2"

Credits: Wikipedia

                https://www.mechanicwiz.com/

INFILTRATION WELLS | | CONSTRUCTION OF INFILTRATION WELLS

          In this article we are going to discuss about the construction of infiltration well with the help of appropriate diagrams.

          Infiltration wells are Shallow wells constructed under the beds of rivers and canals. These wells are best suited for Indian conditions where there are deposits of sand and porous material a minimum of 3 mtr deep in river beds. In sand beds the water penetrates (Infiltrate) faster than clay (or) silty soil beds. As the water passes through the sand, which acts as filter, due to this all suspended organic and inorganic impurities will get removed.

          So, the standards of such water is better than river water. Both infiltration wells and infiltration galleries are based on the same principle. A large number of wells are constructed in the river bed and they are connected to an inspection well. The water flows under gravity from these wells to the inspection well and then towards Jack-well from where it is pumped.

          In order to obtain large quantity of water, infiltration wells are sunk in series in the bank of river. They are constructed of brick masonry with open joints. These are generally covered at top and kept open at bottom.

          The various infiltration wells are connected by porous pipes to a sump well called Jack well. The water reacting the jack well from different infiltration well is lifted, treated and distributed to the consumers.

Purpose of construction of Infiltration wells:

•  Preserving and improving the quality and quantity of ground water.

• To help cope with water shortages.

• Cultivating environmental awareness.

• Conserve and save water resources long term.

Factors to Consider in Making the well of Infiltration:

(i) Topography:

The valley regions are more favorable than the slopes and the hilltops.

(ii) Climate:

The climate is a major factor to consider in planning the filtration wells. The region's annual rainfall, intensity of sunlight, maximum temperature and humidity are of considerable value. Areas having heavy (or) moderate rainfall favor more water to percolate in the soil and rocks layers, and get stored on impermeable layers to form aquifers.

Intensity of summer days evaporates and depletes ground water through direct evaporation from shallow depths and evapotranspiration through plants. Areas of low rainfall and extreme summer conditions do not favor storage of ground water at shallow depth and therefore the wells do not yield much water. Semi-arid zones are more favorable than the arid zones.

(iii) Vegetation:

Vegetation can flourish well where the ground water is available at shallow depths. The trees of forests draw their requirements directly from the 'Zone of Saturation'. Such plants are known as 'Phreatophytes'. Some plants can exist under arid conditions by absorbing the soil moisture (intermediate (or) vadose water) in the zone of aeration and store water in their thick fleshy leaves and stems. Such plants are known as 'Xerophytes'.

By studying the vegetation of the area, the condition of ground water can be assessed. This vegetation indicates large storage of ground water at shallow depths whereas bald hillocks with large number of Xerophytes indicate the scarcity of ground water at shallow depths.

(iv) Geology of the area:

Areas comprising thick soil (or) alluvium cover, highly weathered, fractured, jointed (or) sheared and porous rocks indicates good storage of groundwater, whereas bald hillocks of massive igneous and metamorphic rocks or impermeable shales indicate paucity of ground water.

(v) Porosity, permeability and Alteration of Rocks:

The state of the soil affects the size of the ground penetrating power of the rain. Thus highly porous, permeable and altered zones of dense rocks encourage storage of ground water. Massive rocks do not permit the water to sink. So while constructing infiltration wells we should take soil physical properties into consideration.

(vi) Socio-economic conditions of society:

Planning infiltration wells should pay attention to the social condition of the economy. For example, in a good economy, the cost of infiltration wells can be charged to the community and its construction can be made from a material that is really strong.

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