Difference between revisions of "Biogas-Plant/C3/Construction-of-the-Dome/English-timed"
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− | | Hello | + | | Hello everyone!! Welcome to this '''Spoken Tutorial''' on '''construction of the dome''' of the '''digester tank'''. |
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| 00:28 | | 00:28 | ||
− | | Dome is an arch like structure placed on the | + | | Dome is an arch like structure placed on the digester tank where the biogas is collected. |
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|01:00 | |01:00 | ||
| Let’s begin. | | Let’s begin. | ||
− | First, make a circle of 7 feet | + | First, make a circle of 7 feet 6 inches diameter with lime powder. |
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| 01:27 | | 01:27 | ||
− | | Next, hammer twelve 10- | + | | Next, hammer twelve 10-inches steel rods all along the marked circumference. |
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|01:35 | |01:35 | ||
− | |Hammer 10- | + | |Hammer 10-inches steel rods up to 2 inches in the ground. |
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| 01:53 | | 01:53 | ||
− | | With the 12-feet long steel rods, we’ll make an outer circle around the hammered 10- | + | | With the 12-feet long steel rods, we’ll make an outer circle around the hammered 10-inches steel rods. |
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| 04:57 | | 04:57 | ||
− | | The 12 feet steel rod arches should be at an angular separation of 60 | + | | The 12 feet steel rod arches should be at an angular separation of 60 degrees at the base. |
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|06:54 | |06:54 | ||
− | |* | + | |* the length of the steel rod would depend upon the position of the circular ring on the frame. |
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|17:02 | |17:02 | ||
− | |* | + | |* longer steel rods would be required as we gradually go from top to bottom. |
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| 07:53 | | 07:53 | ||
− | |For the third ring, 9 feet and 8 inches steel rod would be required | + | |For the third ring, 9 feet and 8 inches steel rod would be required; |
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|08:04 | |08:04 | ||
− | |Fourth ring will require 12 feet 3 inches long steel rod | + | |Fourth ring will require 12 feet 3 inches long steel rod; |
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| 08:15 | | 08:15 | ||
− | |The fifth ring will need 14 feet and 10 inches long steel rod | + | |The fifth ring will need 14 feet and 10 inches long steel rod; |
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| 08:27 | | 08:27 | ||
− | |Sixth ring will require 17 feet and 4 inches long rod | + | |Sixth ring will require 17 feet and 4 inches long rod; |
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| 09:17 | | 09:17 | ||
− | |The | + | |The seventh ring will require 20 feet and 10 inches long steel rod. |
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| 10:14 | | 10:14 | ||
− | | Please note | + | | Please note that if you follow the measurements mentioned earlier then you will get a uniform distance of 8 inches between each circular ring. |
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| 10:32 | | 10:32 | ||
− | |The distance between these two hooves should be 8 inches | + | |The distance between these two hooves should be 8 inches |
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| 10:37 | | 10:37 | ||
− | | | + | |and it should fit in between two circular rings as shown here. |
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| 11:52 | | 11:52 | ||
− | | The | + | | The 4 feet 7 inches long steel rod has to be bent and tied to the 6th ring. |
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| 12:06 | | 12:06 | ||
− | |Note that in both cases extra 3 inches have been left at the top for the ease of tying the steel wire to the circular rings. | + | |Note that in both cases, extra 3 inches have been left at the top for the ease of tying the steel wire to the circular rings. |
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| 12:47 | | 12:47 | ||
− | | Use 7th and 8th | + | | Use 7th and 8th rings to make gap of the mentioned size. |
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| 12:53 | | 12:53 | ||
− | |Bend the 7th rod to make the upper side of the entrance, as shown in the image | + | |Bend the 7th rod to make the upper side of the entrance, as shown in the image and bend the 8th ring downward. |
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Revision as of 12:41, 5 December 2016
Time | Narration |
00:01 | Hello everyone!! Welcome to this Spoken Tutorial on construction of the dome of the digester tank. |
00:08 | The tutorials on digging of the pit and laying the foundation are available on Spoken-tutorial.org website. |
00:18 | In this tutorial, we will learn the step-by-step procedure for constructing a dome. |
00:26 | So, what is a dome? |
00:28 | Dome is an arch like structure placed on the digester tank where the biogas is collected. |
00:36 | Construction of the dome is a very interesting and important procedure. |
00:43 | Items used for construction are steel rods, chicken mesh and steel wire. |
00:51 | Detailed specifications of these are mentioned in the tutorial on materials required. |
01:00 | Let’s begin.
First, make a circle of 7 feet 6 inches diameter with lime powder. |
01:08 | Now, put 12 marks on the circumference of the circle and number them from 1 to 12, as shown. |
01:19 | These 12 marks should be separated by a distance of two feet from each other. |
01:27 | Next, hammer twelve 10-inches steel rods all along the marked circumference. |
01:35 | Hammer 10-inches steel rods up to 2 inches in the ground. |
01:42 | Remember that they have to be removed later. |
01:48 | Next comes the use of 12-feet long steel rods. |
01:53 | With the 12-feet long steel rods, we’ll make an outer circle around the hammered 10-inches steel rods. |
02:02 | I will now tell you how to make a circle using the hollow rod. |
02:08 | Use an iron rod having hollow ends. |
02:12 | With this iron rod, bend the 12-feet steel rods to form a circular shape. |
02:19 | Then place the circular steel rods around the smaller 10-inches steel rods, as shown. |
02:28 | We will need two 12 feet rods to complete the circle. |
02:33 | Now tie the circular steel rods to the 10-inch steel rods using steel wires, as shown. |
02:42 | Ensure that the knot is tied very tightly and the steel rod circle is very stable. |
02:49 | This is the base of the dome. |
02:52 | Hence it has to be very strong to bear the load of the plastered dome later. |
02:58 | Now, hammer a 4-feet and 2 inches long bamboo stick in the center of the circle, as shown. |
03:06 | Hammer the bamboo stick up to 2 inches in the ground. |
03:11 | Ensure that it can stand firmly by itself and can be easily removed later. |
03:18 | This bamboo stick should be able to temporarily support the frame of the dome. |
03:24 | Now, let’s start building the frame of the dome. |
03:27 | Again, use the hollow iron rod and bend a 12-ft long steel rod to form an arch like shape. |
03:37 | This arch will give the semi-circular shape to the dome. |
03:41 | Hence, ensure that the arch is symmetric on either side when bent. |
03:48 | Similarly, bend 2 more 12-feet rods to form arches. |
03:55 | Let me explain exactly how the arches have to be placed on the circumference using a diagram. |
04:03 | Secure one end of the arch at rod number 1 and the other end of the arch at rod number 7. |
04:11 | This will ensure perfect symmetry to the arch and it will rest on the bamboo stick in the centre. |
04:19 | Use steel wires to tie the arch together with the hammered 10-inches steel rod and the circular ring. |
04:28 | For tying, make a knot like structure with the steel wire, as shown here. |
04:35 | Do likewise at the opposite end of the arch as well. |
04:40 | Next we will tie two more arches. |
04:44 | Secure the second arch to rod number 3 and rod number 9. |
04:50 | And, secure the third arch to rod number 5 and rod number 11. |
04:57 | The 12 feet steel rod arches should be at an angular separation of 60 degrees at the base. |
05:07 | Now, we have three arches for the frame of the dome. |
05:12 | Next, carefully slide the steel rods at the top such that a small gap is left open in between. |
05:22 | Tie the steel rods using the steel wires as shown. |
05:27 | Intersection of the three arches will look like a triangle. |
05:32 | The sides of the triangle should be approximately 2.5 inches as shown in the image. |
05:40 | The top view of the framework should look like this after tying. |
05:46 | What you see here is the mason showing the exact position of the open triangular gap using the bamboo stick. |
05:54 | This gap is where the main gas pipe of 1 inch diameter will fit. |
06:01 | Once the arches have been fixed, we have to make circular rings with the remaining 12-feet steel rods. |
06:11 | First let us understand how to make these rings with the help of a diagram. |
06:17 | This is the framework we constructed so far, |
06:21 | circular base and semi-circular arches. |
06:26 | Now we need to fix 8 circular rings such that they can be placed on the arches, as shown. |
06:34 | The rings have to be uniformly separated by a distance of 8 inches between each of them. |
06:43 | To make circular rings, start from the top and gradually move downwards. |
06:49 | Two things to keep in mind while making circular rings are: |
06:54 | * the length of the steel rod would depend upon the position of the circular ring on the frame. |
17:02 | * longer steel rods would be required as we gradually go from top to bottom. |
07:09 | We will first have to cut the steel rods to the required length before we fix the rings. |
07:16 | So, let’s do that. |
07:18 | For the first ring which is the smallest ring at the top, we will need approximately 4 feet and 7 inches steel rod, adding 2 feet extra for tying. |
07:33 | Diameter of this circular ring will be 10 inches. |
07:39 | For the second ring, we will need approximately 7 feet and 1 inch of steel rod. |
07:47 | Diameter of this ring will be 1 foot and 7 inches. |
07:53 | For the third ring, 9 feet and 8 inches steel rod would be required; |
07:59 | diameter would be 2 feet and 5 inches. |
08:04 | Fourth ring will require 12 feet 3 inches long steel rod; |
08:11 | diameter of this ring will be 3 feet and 3 inches. |
08:15 | The fifth ring will need 14 feet and 10 inches long steel rod; |
08:21 | diameter of this ring will be 4 feet and 1 inch. |
08:27 | Sixth ring will require 17 feet and 4 inches long rod; |
08:33 | diameter of this ring will be 4 feet and 10 inches. |
08:39 | Remember, as mentioned while explaining the first circular ring , an extra 2 feet has been calculated for tying the rods together with steel wires, for all the 8 rings. |
08:54 | And the diameter for all the 8 rings is calculated excluding the 6 inches. |
09:02 | Now come the 7th and 8th rings. |
09:06 | Both will be used for making the circular rings and also the entrance of the dome. |
09:13 | Measurements for these two rings are- |
09:17 | The seventh ring will require 20 feet and 10 inches long steel rod. |
09:23 | And, for eighth ring 23 feet and 5 inches long steel rod would be required. |
09:31 | Keep in mind that this includes the measurement for the bent rods as well. |
09:38 | As soon as three circular rings are placed, an important thing to be done is: |
09:45 | Place 6 bamboo sticks of length 4 feet in an inclined position inside the frame of the dome. |
09:54 | Note that bamboo sticks have to be spread out uniformly from the centre of the base. |
10:02 | And, should be firmly rested against the circular rings or the arches. |
10:09 | These sticks will further give support to the frame of the dome. |
10:14 | Please note that if you follow the measurements mentioned earlier then you will get a uniform distance of 8 inches between each circular ring. |
10:26 | To confirm this, use a 1 foot steel scale having two hooves. |
10:32 | The distance between these two hooves should be 8 inches |
10:37 | and it should fit in between two circular rings as shown here. |
10:43 | However, you may ignore minor variations, if any. |
10:48 | Just after placing the 6th circular ring, an important thing to be done is to fix vertical rods on the frame. |
10:58 | I will explain how to do that: |
11:01 | Between two half-arches, fix a steel rod of length 5 feet and 5 inches bisecting the two main arches. |
11:13 | Tie this rod using steel wires from the base ring up to the first ring as shown in the image. |
11:22 | Similarly, fix two more steel rods of 4 feet and 7 inches, bisecting the half-arch and the 5 feet and 5 inches steel rod. |
11:36 | Tie these two rods using steel wires from the base ring up to the second ring, as shown. |
11:44 | Please note- between the 5th and 6th 10 inches hammered steel rods, do the following: |
11:52 | The 4 feet 7 inches long steel rod has to be bent and tied to the 6th ring. |
12:00 | This is done to make space for the entrance of the dome as shown in the image. |
12:06 | Note that in both cases, extra 3 inches have been left at the top for the ease of tying the steel wire to the circular rings. |
12:17 | Now we will fix the last two circular rings i.e. the 7th and 8th ring. |
12:23 | However, it is to be noted that between 6th and 8th ring will be the gap or the entrance to the dome. |
12:32 | This gap should be big enough for the mason to enter inside the dome. |
12:39 | Size of this gap would be approximately 2 feet of width and 2 feet of height. |
12:47 | Use 7th and 8th rings to make gap of the mentioned size. |
12:53 | Bend the 7th rod to make the upper side of the entrance, as shown in the image and bend the 8th ring downward. |
13:04 | This will make the lower end of the gap or entrance as shown in the image. |
13:10 | Now, tie the bent 7th and 8th rings firmly with steel wires. |
13:17 | Next comes covering the frame of the dome with chicken mesh. |
13:23 | Use a metal scissor to cut the required size of the chicken mesh. |
13:29 | Start covering the frame tightly with the mesh, from top to bottom. |
13:35 | To tie the mesh to the frame, stretch the mesh tightly and tie it to the frame with steel wires. |
13:45 | This can be done by using a metal hook. |
13:49 | To tighten the layers of the chicken mesh-insert the hook into the hole(s) of the two layers. |
13:57 | Rotate the hook by stretching the mesh and simultaneously entwining the meshes. |
14:04 | Please note- if the chicken mesh is not stretched tightly then cracks might appear later while plastering the dome. |
14:15 | Remember to leave an extra 4-5 inches of chicken mesh at the nape of the frame. |
14:23 | Reason for this will be explained while fixing the dome on the digester tank. |
14:29 | The entire frame should be covered with 3 bundles of chicken mesh. |
14:35 | This would form approximately 3 layers over the dome. |
14:40 | The multiple layers of chicken mesh will help to hold the cement firmly while plastering the dome. |
14:48 | Chicken mesh covering the entrance to the dome, should be cut with scissors. |
14:53 | What you see here is the mason getting inside the dome through the same gap or the entrance. |
15:00 | Once the chicken mesh is fixed, remove the bamboo sticks placed inside for support. |
15:07 | Please note that the sticks have to be gently removed so as to not disturb the frame of the dome. |
15:15 | Do so carefully and slowly. |
15:18 | The mesh dome is now ready and can be placed on the digester tank. |
15:24 | Before shifting, untie the 10 inches hammered steel rod from the base ring |
15:31 | and make sure of re-tying the loose ends of the mesh. |
15:36 | This brings us to the end of this tutorial of constructing a dome for the biogas plant. |
15:44 | Fixing of the dome on the biogas plant will be explained in a later tutorial. |
15:50 | Let us summarize. In this tutorial, we learnt the step-by-step procedure to construct the dome of the digester tank. |
16:00 | This video was created by Spoken Tutorial Project with inputs from Rural-ICT team, IIT Bombay. |
16:08 | More information on these projects can be found at these links. |
16:17 | This is Bella Tony along with the animation team of the Spoken Tutorial project, signing off.
Thank you for joining. |