YR 12th Year of Membership
Bar Screen Cleaners
A manual/automatic bar screen cleaner mechanically cleans out bar screens with the help of a grab carriage having anti-wedging design. The grab carriage runs on guide channels which are fixed to the concrete walls below the floor level. The channels run from the sump base up to the top of the discharge point. Multiple channels can be cleaned by a mobile bar cleaner moving on rails.
The grab travels down in an open position. When it meets an obstruction or reaches the bottom of the chamber, it closes automatically (using a slack cable mechanism). It then travels upwards with the collected debris and discharges it on a conveyor or waste collector.
Necessary safety switches and alarms are provided to detect slackness of rope, open/close status of grab to enable automatic operation of the cleaner.
The mobile version of the cleaner can be stationed by means of proximity switches at the channel requiring cleaning.
Macmet supplies debris filters for protecting the heat transfer equipment against small to medium size wastes that may have passed through upstream screens.
The Debris Filter is capable of handling various forms of debris/sludge i.e. suspended particles/matter, mussels, grass, leaves, wood pieces, etc. The strainer effectively prevents fouling by capturing and ejecting all debris in an optimal manner. The optimal cleaning capability is achieved through the incorporation of dedicated suction ports for the two basic classes of debris - coarse and fibrous.
When fouling creates the critical predetermined pressure across the filter, the backwash/debris evacuation sequence is initiated. The valve on the debris evacuation pipe automatically opens and the evacuation rotor is actuated. The differential pressure at the portals creates the vacuum by which all the debris is evacuated. The rotor continues to clean the filter until allowable differential pressure exists. The rotor then is automatically stopped and the valve on the evacuation is closed.
Penstocks are the most commonly used isolation devices. It requires practically no maintenance. It can have a cast iron body or a fabricated body with exchangeable sealing arrangement made of soft material. It can be manually operated or power operated.
The main features of penstocks are:
1. Exchangeable seals
2. Manually or electrically operated
3. Wall bolted frames (max size of 1300 mm)
4. Non-rising/Rising stem design
5. Roller guided door for ease of operation
6. Guides having adjustable wedges
Stop Log Gates
When intake channels or intake equipment need repairs and absolute sealing out of water is not necessary, the stop log gate is used as a shut off device.
Depending on the handling facility and headroom available at site, the stop log gate can be of one or several segments. To ensure effective sealing, replaceable rubber profile sealing is provided on all sides. The gates are designed considering maximum water head. The skin plate is adequately reinforced with stiffeners.
A condenser tube cleaning system is efficient only when it circulates a sufficient number of cleaning balls having an adequate diameter. The ball monitor continuously checks the condition of circulating balls, sorts the balls into usable and worn out groups and counts the number of balls in circulation.
Automatic Ball Feeder for Macmet's Condenser Tube Cleaning SystemA centralised automatic ball feeder, capable of feeding upto 12 tube cleaning systems from a single location close to the condensers, is provided as per the specific requirement of the customer. It is controlled by a Programmable Logic Controller and receives information from each ball monitor. The ball feeder requires a source of water with an available pressure higher than the cooling water pressure at the condenser inlet. This water is used only for soaking the balls and injecting them into the cleaning system.
Cleaning Balls for Macmet's Condenser Tube Cleaning SystemMACMET also supplies cleaning balls of TECHNOS make along with the CTCS. TECHNOS ball quality assures:
- Improved cleaning efficiency
- Preserved integrity of protective tube film
- Maximised ball life
Sponge rubber balls are manufactured in TECHNOS own plant. First grade natural rubber is used and blended with other material which gives them the final quality. Balls having different hardness and sizes are provided depending on the specific application.
Tube Cleaning Systems
MACMET offers Condenser Tube Cleaning Systems (CTCS) and Debris Filters in technical association with TECHNOS ET COMPAGNIE, France.
TECHNOS is one of the leading suppliers of CTCS and Debris Filters for Power Utilities, Refineries and Process Industries with worldwide supply reference of more than 1000 installations, capacities of the units ranging from 2 MW to 1300 MW.
The continuous cleaning of condensers and heat exchangers maintains their efficiency of heat transfer without mechanical or chemical cleaning of the tubes and without increasing the number of outages.
Cleaning of internal tube surface is accomplished by continuous circulation of sponge rubber balls with sizes slightly larger than the tube diameter. These sponge rubber balls are injected into the cooling water inlet header. The water flow carries these balls into the inlet water boxes, then through the tubes and finally into the ball strainer located at the cooling water outlet header.
From the strainer section, the balls are extracted and pumped through the ball monitor to the ball collector and then to the cooling water inlet header. The ball collector acts as the storage vessel for the sponge rubber balls during backwashing of the strainer grids.
Idlers & Pulleys
Macmet supplies idlers for trouble free conveyor operations. A wide range of 'sealed for life' type idlers, either with seize resistant or deep groove ball bearings, are manufactured and supplied to suit specific requirements and applications.
Both fixed bracket type (in-line & staggered) idlers and garland type idlers with roll diameters from 76.1 mm to 219.1 mm are manufactured by MACMET. All fixed bracket idlers will be drop in slot type. Slotted holes will be provided at the base of the idlers bracket to permit adjustment up to 5 mm on each side of the true center for training of the belt. All idlers conform strictly to IS:8598.
The idlers are provided with sufficient quantity of servo grade grease and sealed for life. Special type bearing housing are made out of deep drawn quality steel sheets, idler rollers are made with ERW black tubes conforming to IS:9295. The out of roundness of the rollers will be within +/- 0.5mm. Tubes are cut into required lengths and both ends are bored to required accuracy and to achieve concentricity. The bearing housings are made out of deep drawn quality steel sheets.
Macmet pulleys are time tested drive components for all types of belt conveyor systems. They are safe, robust and reliable with long service life. Basic pulley diameters are 250, 315, 400, 500, 630, 800, 1000, 1250, 1400 & 1600 mm. All pulleys are made conforming to IS:8531. The pulleys, unless otherwise agreed with the customer, are rolled and fabricated from low carbon steel plates with end/center disc welded to the shell. For specific requirements and applications, turbo diaphragm type cast steel end discs are also used. All pulley shafts are made from C-40/EN-8 grade steel. The outer surface of the pulley shells are machined to specific tolerances.
Bar Screens & Trash Racks
Filtration at the first stage of water intake system is done by Bar Screens (also known as Trash Racks). These remove bulky and coarse material. The spacing of bars on such bar screens depends upon the quality of filtered water required. To prevent material too coarse from reaching the travelling band screens, bar screens may be used in two stages where the first screen with wider bar spacing remove bulky solids; a second bar screen with smaller bar spacing then remove debris still coarse enough to clog travelling band screens installed downstream for finer screening.
Bar screens can be categorized into two types:
1. Removable Type
2. Fixed Type
In case of removable type, single or multiple segments of bar screens, with the help of a lifting beam, are lowered into or raised out of the intake chamber by means of guides installed on the sides walls. The beam lifts out the segments for necessary cleaning of the screens.
In case of fixed type, bar screens, consisting of steel frames of welded design over which flat bar sections are fixed by bolting/welding, are fixed to the bottom of the chamber by grouting/bolting. The flats are suitably spaced to meet design requirements. Interchangeable bar sections are provided for easy replacement. Fixed type bar screens have to be cleaned out by bar screen cleaning equipment.
On the basis of design differential water head, suitable selections are made of structural parts, screen bars and supports.
Travelling Band Screens
Screening of large volumes of water meant for industrial use can be done by MACMET's Travelling Band Screens which remove floating/suspended material that pose potential danger to downstream industrial equipment.
MACMET's Travelling Band Screens consist of Basket frames fitted with screen meshes and arranged in a link chain system. The intake water flows through these baskets, with the debris left trapped behind in the baskets. The debris so collected is carried to the top by the revolving band screen. At the top, jets of water wash out the debris into a refuse disposal trench. Highly efficient spray nozzles fitted in the spray header pipe wash out the screening baskets. There is also the option of fitting an internal cleaning device for cleaning the spray nozzles of the spray header pipe.
Such long conveyors normally follow the contour of the terrain which often involves curves in both horizontal and vertical planes. Availability of high strength steel cord belting and sophisticated dynamic model analysis for assessing the behaviour of the conveyor along the curves have encouraged customers to opt for long distance conveyors.
Macmet is the leading supplier of Pipe Conveyors in India. Macmet was the first to supply an indigenously designed pipe conveyor for ACC Limited. Macmet has also supplied India's longest (2.4 km) EP belting pipe conveyor for ACC Ltd's Chaibasa Unit. India has recently commissioned the world's second longest pipe conveyor (7 km) carrying 1500 tons of coal per hour from mines to O. P. Jindal Super Thermal Power Plant.
Pipe conveyors are an environmental friendly solution for conveying bulk material with zero spillage and ability to cover terrain difficult to negotiate by conventional conveyors.
MACMET manufactures belt trippers, either fixed or travelling type with one/two/three way chutes, used for intermittent side discharge of material from the belt conveyor.
Belt trippers are commonly used for discharging material either to a number of downstream conveyors and other handling equipment or to storage bunkers with feed opening at floor level.
Travelling trippers are provided with bunker sealing device. MACMET supplies trippers, up to 500 m travel length, for various applications.
- Traveling hoppers are used for transfer of material associated with short period, intermediate storage.
- The hopper is mounted on a fabricated bogie provided with independent long travel drive. A dust suppression system is provided to arrest the emitting dust generated during transfer of material for protecting the surrounding environment. Material reclaimed from storage yards or unloaded from water borne vessels is discharged to the downstream conveyor using traveling hoppers.
- Traveling hoppers move on rails alongside the storage yard and unloading bay to receive material. For regulated discharge of materials, hoppers are equipped with feeders at the bottom.