I have a small endoscopic camera (custom made). I wanted to push the camera inside a horizontal pipe of dimensions varying from (25 mm to 65 mm ID). But the wire attached to the camera is not stiff enough to push the camera. After a certain length, camera stops moving (cz the wire coils inside the pipe). But I have seen Companies like Olympus etc., push their camera even up to 25 meters. I know that they have a special cover over the wire which is stiff and flexible for pushing the camera. How can I make a cover similar to that ? I have enquired many places but could not find a solution. Thanks in advance for your help.
You can buy endoscope or borescope cables which should "just work," though 20m is longer than the typical cable you will find on Amazon or Ebay.
If you want to try making your own, look at the design of Bowden cables (used for brake cables on bikes, etc). The outer cover is made like a coil spring, so it can bend around a large radius but won't "buckle" into a small radius at one point.
You might also consider flexible chimney sweeping rods, which are made in 1 or 2 meter lengths which you can join together as you move the camera down the pipe. They would have the disadvantage that the camera cable would be separate from the rods, unlike a Bowden cable where it would be inside the cable and protected from dirt and damage.
In fact chimney sweeping suppliers sell inspection cameras that fit onto standard sweeping rods, and are self contained with battery power and a wireless data transmission link, so you don't need a separate cable to the camera.
Most electrical engineers use an electrician Conduit Ducting wire for that (which you could use in your cable setup), but in your case it probably easier to use a piece of string and a vacuum cleaner. Put the vacuum cleaner at one end and suck the piece of string through. Then pull the camera through using the string like explained in How to get cables in a long pipe - with vacuum cleaner
I think I have a very similar USB camera.
I tape it to an electrician's tool called, in trade jargon, fish tape, this is a narrow strong, springy tape, which is uses to pull the wires through conduits.
My sewer line is prone to clogging at the point when it connects to old City sewer main, which even though is public, has never been serviced by the city because it runs in my property, (easement).
I have taped a keychain led flash light to this fish tape and it helps a lot.