What is the ductile iron manhole cover?
Underground space or utility lines such as drainage systems and telephone wires are always found in urban centers. Regular maintenance is required in that subsurface location. As a result, technicians must pass through an access hole the size of a human body to perform maintenance. This hole is then referred to as a manhole. We should also use the manhole cover to close this manhole.
So, a ductile iron manhole cover is a removable component that is used to cover a manhole or utility line access hole in the underground space. A ductile iron manhole cover is made up of two parts: the frame and the cover.
The manhole cover’s purpose is to keep people out of utility lines unless they are technicians. Also, one of the most important functions of a manhole cover is to keep people safe from falling into the hole.
Ductile Iron Manhole Cover Specification
1. Design
a. Round Manhole Cover
A round manhole cover has more advantages compared to a square manhole cover because:
- You can more easily move round manhole cover by rotating.
- The round manhole cover has a better strength because it has no residual stress on its side. The residual stress evenly distributed on all circular sides.
- A round manhole cover will not fall in when you open it by rotating. While the square manhole cover may fall when you open it diagonally.
b. Square Manhole Cover
Although less good than the round manhole cover, for specific projects would be more proper if we select a square manhole cover. A square manhole cover typically used in the pedestrian zone construction project. This is because the square manhole cover will match with ceramic installed on the pedestrian zone floor.
c. Customized Manhole Cover
A customized manhole cover is a manhole cover that manufactured based on customer demand. Since the size and shape of the manhole cover according to the needs of each project. Also, a customized motif manhole cover has motifs in the form of a company logo, project name, and year. Furthermore, the color of the manhole cover can also be customized. If a standard manhole cover has black color, a custom manhole cover has another color.
While the standard sizes of manhole covers are 600, 700, 800, and 900. For the standard design manhole cover, the motifs are non-slip patterns like squares pattern, rectangular pattern, and diamond pattern.
2. Material characteristics
The ductile iron material is a grade A (high-grade) of cast iron material. Hence this material has the characteristics as mentioned below:
- Easy designing
- Low cost
- Have a good ability of machining
- Have a high score of loading test, so it is not easy to crack
- Circular graphite
- Have a good pull test
- Capable of reducing vibration, so it is noiseless
- Wear-resistant
- More strength than cast iron
3. Strength capacity
a. Medium duty manhole cover
A medium-duty manhole cover is a manhole cover that has middle-class strength. This type of manhole cover is designed to withstand light load such as family car up to light freight car. Typical projects that use medium-duty manhole cover are residential, hotels, and apartments.
b. Heavy-duty manhole cover
A heavy-duty manhole cover is a manhole cover that has heavy-class strength. Hence it can withstand heavy-weight vehicles such as containers and airplanes. Heavy-duty manhole cover typically uses at the airport area or another area which passed by heavy-weight vehicles.
Ductile Iron Manhole Cover Manufacturing Process
The manufacturing process of ductile iron manhole cover consists of 6 steps:
Step 1: Design and Simulation
At this step, the engineer redrawing the manhole cover design from the customer. To drawing the design, the engineer uses a 2D drawing program, a 3D drawing program, and a simulation program. Then from this process, we will know the shape and weight of the cast iron manhole cover. Therefore engineers can estimate how much material needs in the manufacturing process.
Step 2: Making the pattern
Materials to make manhole cover patterns are wood and metal. It depends on the production measure of the manhole cover. If a few productions, we use a wood pattern. While for the large measure production, we use a metal pattern.
Furthermore, we must make sure that the pattern conforms with the design in step 1.
Step 3: Moulding Process
The manufacturing process of a ductile iron manhole cover uses Sand Molding and Resin Bonded Sand Molding. Sand used as molding because it is able to absorb heat. So that the casting product can immediately chill and formed.
Step 4: Melting
Melting is the process of melting the raw materials of a ductile iron manhole cover in the induction furnace. We use an induction furnace because it has advantages in production speed and the material composition is quite good.
After the raw materials melt, then pour them into the mold. Wait for it to solidify and removed it from the mold.
Step 5: Finishing
The finishing step consists of shot blasting, grinding, and painting. Shot blasting useful for removing the sands that still clinging to the manhole cover.
Grinding aims to cut sharp edges so that the manhole cover becomes more refined. Also, make it easier to paint.
While painting useful to give colors on manhole cover so the manhole cover looks better and more beautiful.
Step 6: Quality Control
The last, manhole cover that has been completed in the finishing process must pass through a quality control process. This process consists of:
- Measure the dimensions suitability
- Chemical composition test
- Mechanical properties test
- Physical properties test
The projects that use ductile iron manhole covers
Infiniferro has experienced in supplying ductile iron manhole covers for various projects in Indonesia:
1. Airport
The use of manhole cover at the airport is on the apron (airplane parking area) and sometimes also on the runway. The airports that have used ductile iron manhole cover from Infiniferro is Ngurah Rai International Airport in Bali.
We have been supplying manhole covers to I Gusti Ngurah Rai International Airport two times. The first supply was in 2013 with 4 units of manhole covers. While the second supply was in 2017 with 77 units of manhole covers.
Manhole cover of I Gusti Ngurah Rai Internasional Airport has an embossed logo and name of the project owner. So that it can function as the project identity.
2. MRT (Mass Rapid Transit)
MRT that using manhole cover from Infiniferro is MRT of Jakarta. In this project, we have supplied 8 units of manhole covers. There are 6 units in the first supply, then 2 units in the second supply.
Manhole covers of MRT have a round shape with a diameter of 600 and a square frame. There is a hinge to unify the frame and cover. So the frame and cover are not easy to lose or lost because of stolen.
3. Power Plants
While the power plant that has used manhole cover from Infiniferro is Celukan Bawang Power Plant in Bali. This power plant uses 87 units of manhole covers.
Manhole covers of Celukan Bawang Power Plant have a round shape and the frames are round too. This manhole cover designed without a hinge, so as to more security it uses wires.
Sifiso says
Good day we looking for some dictile manhole covers and frames, kindly let us know if you can assist,
admin says
Hello Mr. Sifiso, we can assist ductile manhole covers and frames for your project. Please inform your needs via email info@infiniferro.com.
Thank you
Marketing Team