[ppb_header_video size=”one” title=”” subtitle=”” textalign=”center” poster=”https://epsl-bd.com/wp-content/uploads/2018/10/home_img1.png” mp4=”https://epsl-bd.com/wp-content/uploads/2018/03/video1.mp4″ webm=”https://epsl-bd.com/wp-content/uploads/2018/03/video1.webm” ogv=”” fontcolor=”#ffffff” bgcolor=”#000000″ opacity=”15″ height=”80″ custom_css=”” ]
MANUFACTURING PROCESS / PRODUCTION TECHNIQUE OF SPC POLES
ERECTORS POLES & STRUCTURES LTD.[/ppb_header_video]
[ppb_content_half_bg size=”one” title=”Aggregates on arrival at factory ” slug=”” subtitle=”” background=”https://epsl-bd.com/wp-content/uploads/2015/06/galllery_19.png” background_position=”top” padding=”30″ bgcolor=”#ffffff” opacity=”100″ fontcolor=”” align=”left” custom_css=”” ]Aggregates on arrival at factory premises are once again checked and restored to eliminate mud and other foreign materials, shale or rock charcoal. Boulders from the stacks are crushed by stone crusher and after crashing, the aggregates are sieved and classified in sizes ranging from 14mm over 12mm, under 10mm over 7mm and under 3mm to 0mm. The proper sizes aggregates are then washed and re-stocked in the segregates compartment. Aggregates are then placed into batching plant hoppers.
High Tension Wire are cut to a certain measurement according to the length of pole with tolerance and held top and bottom tension plate and placed to auto head forming machine for head forming and hanged to casing stand for spiral filled and tied wherever necessary with pre-stressing wire by soft wire ties.
Two parts of mould are cleaned properly and the casing to be placed into female side of the mould and then spindle with UPVC sleeve to fix according to the drawing and design. [/ppb_content_half_bg]
[ppb_content_half_bg size=”one” title=”Various sized aggregates” slug=”” subtitle=”” background=”https://epsl-bd.com/wp-content/uploads/2015/06/galllery_10.png” background_position=”center” padding=”30″ bgcolor=”” opacity=”100″ fontcolor=”” align=”right” custom_css=”” ]Various sized aggregates for making concrete are already in hopper fall in conveyor belt automatically weighted as per predetermined weight, obtained from concrete mix design and carried to another hopper. This hopper is then lifted and dumps its contents into the mixer drum. Screw conveyor for cement is switched on, and it conveys cement from cement silo to cement hopper, where it is automatically switched off and the cement falls into the mixture from the cement hopper. The mixer is then mixed for a designed period and water added through a preset flow meter. The prepared concrete is then fall in a power driven concrete feeder-trolley to carry the materials for casting into mould.
Concrete are mixed for a minimum of 3 minutes mixing continuously until the materials is transferred to concrete feeder-trolley. The mixed concrete is thoroughly and uniformly mixed and concrete is uniform in texture and colour. The entire batch is discharged from the mixing before recharging commences.
Prepared concrete is transferred from mixture to the mold by feeder-trolley. The trolley distributes the concrete into the mold uniformly in a proper way so that a pole with required thickness and strength always obtained. Rate of replacement of concrete is such that concrete at all time remains plastic and flows readily into the mould. The placement of concrete in the mould is completed within 10-12 minutes after the introduction of the mixing water into the cement and aggregates in the concrete mixture drum. Each mould is filled with concrete as a continuous operation. [/ppb_content_half_bg]
[ppb_content_half_bg size=”one” title=”During the operation” slug=”” subtitle=”” background=”https://epsl-bd.com/wp-content/uploads/2015/06/galllery_06.png” background_position=”top” padding=”30″ bgcolor=”” opacity=”100″ fontcolor=”” align=”left” custom_css=”” ]During the operation some mixture is taken to make cubes/cylinder testing, cubes/cylinders are subjected to some condition as of pole and cubes are tested in the laboratory of ERECTORS POLES & STRUCTURES LTD.
Top half (Male part) of the mould is placed into the bottom half of the mould and tighten nut bolts by auto air wrench. Pre-stressing wires are then pre-stressed with the pre-stressing machine then filled mould is lifted by crane and placed on to the spinning machine.
In the spinning machine mould is rotated initially at speed ranging between 250rpm to 400 rpm for about 4 minutes to allow axial flow of concrete along the inner surface of the mould for equal distribution of concrete, at medium rpm of about 800rpm for about 01 minute and thereafter at high speed of 1100rpm for 10 minutes for deep, dense compaction through centrifugal force. [/ppb_content_half_bg]
[ppb_content_half_bg size=”one” title=”Once the spinning is completed” slug=”” subtitle=”” background=”https://epsl-bd.com/wp-content/uploads/2015/06/galllery_04.png” background_position=”center” padding=”30″ bgcolor=”” opacity=”100″ fontcolor=”” align=”right” custom_css=”” ]Once the spinning is completed, the moulds is taken off from spinning machine to stream curing and are properly stacked where an initial maturing period is allowed after casting the concrete and before any increase above ambient temperature begins. This maturing is measured from the time of completion of casting to the beginning of increasing the temperature for elevated temperature curing. All pins used to form holes in pole which pass through the mould and concrete are withdrawn to prevent the damage to the concrete caused by differential expansions between the mould and the concrete. After the maturity period heat is introduced to the concrete that limits the temperature to raise to maximum of 24°C per hour i.e. not more than 6°C per 15 minutes. Care is taken to ensure that the maximum temperature during steam curing cycle is not exceeded by 75°C. The rate of cooling is kept steady and gradual so as prevent any thermal shock due to differential cooling.
Once the mould and concrete therein has completely cooled off. Once the pre-stressing washer has been taken off the two halves of the moulds are separated and the spun pole is rolled over. The spun pole is then conveyed by overhead crane to the water curing areas. Where they are cured by water for 7days by submerging them in water. The poles are then lifted and stacked in the curing yard where poles are cured by sprinkled water for a further period of 21 days, where it is ensured that all surfaces to the atmosphere are constantly wet of dump. The poles are then ready for delivery. [/ppb_content_half_bg]