problem with air bladder

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motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

problem with air bladder

Post by motoman »

I have faced a problem with my air bladder. I gradually increased the pressure in a fire hose but after the pressure reaches 60 psi appeared strange squeak. I left the hoses at night and in the morning they were less than one atmosphere. Later, I spotted a place where the air out and was upset. Because of the pressure fabric of hose beginning to come out of the mount. I did not expect this. What would you suggest in this case?
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The line on the last picture shows the place where fiber started to come out. This is the place where air blown out from under steel corners.
Has somebody faced such kind of problem?
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

Looks like not enough clamping force. Hose got pulled out and i assume ripped at the screw hole.
Tom
motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

bull's-eye. but I twisted the bolts that there are forces.
And afterwards I found it strange.
The one more thing. These fire hoses are not elastic as in US they are rigid made of nylon thread and rubber from inside. May be it is the reason...
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

Use thicker L-profile (see below), grade 8 bolts and maybe silicone between L-profile and hose. I assume the nylon is quite slippery so the silicone or something similar will help against pullout. Nothing will move anymore (hopefully). And btw. use washers ;)

Check if the L-profile warps when you screw it down, if so use thicker one or U-profile or massive flat steel or ...
Tom
motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

I put silicone everywhere but anyway we see the result. Probably I will use thicker L-profile and use washers. Bolts are of 8.8 grade as fr as I remember.
motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

Thank you for the advice!!
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chrismp
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Location: Vienna, Austria

Post by chrismp »

We use the same type of hose without troubles. Our L-profile looks even thinner than yours, but we have grade 8 bolts basically right next to each other with washers.
motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

I dont know what is the problem, today I will use higher grade of bolts and will apply new corners. Still I dont understand, because I screwed bolts as tight as it was possible.
gav wa
Posts: 381
Joined: Tue Feb 18, 2014 8:58 pm
Location: Perth

Post by gav wa »

That's pretty high pressure. I press a fair bit lower than that. But you also might want to look at the sharpness of that L profile. That's a pretty sharp edge you got that hose squeezing against.
I cut some heavy pipe in half and welded the halves on the vertical faces of my clamps.
My angle (L profile) is only aluminium and my holes are about 80mm apart and I have no problems. I also have a hose twice that size. I don't think your issue is the tightness of your bolts.
motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

I figured out that the possible reason was the presence of silicon between hose and corners. Possibly I put too much silicone to insulate holes for bolts. The fiber in central bolt hole torn. I think that after high pressure hose fiber got out.
MadRussian
Posts: 712
Joined: Thu Sep 30, 2010 12:32 pm
Location: USA

Post by MadRussian »

I did firehose collection number of times. always problem under the air connector and never under the bolts. Never use L shape profile always flat stock 3/8 to half inch thick 1 to 2 inch wide. 4 to 5 bolts per each end. Never find need to use silicon or similar products.
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
motoman
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Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

Metal plates are also good variant. I thought about them but they seem to me way heavier then L profile.
JSquare
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Joined: Fri Sep 14, 2012 1:59 pm
Location: NH

Post by JSquare »

motoman wrote:Metal plates are also good variant. I thought about them but they seem to me way heavier then L profile.
Yes. You are right. Look up moment of inertia for beam bending.

A lot of good advice for you here though. Generally, sealing surfaces you want to be clean, flat, and have a lot of clamping force. One other thought is maybe your hole locations are a little funky and you're forcing some wrinkles when you put all the bolts through. You got this though. Just slam funk it and itll work.
motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

let me show you how my air bladder exploded.
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motoman
Posts: 243
Joined: Thu Jan 15, 2015 5:52 am
Location: Ukraine

Post by motoman »

I tried to solve previous problem by placing sandpaper in between L-profile and fire hose for better adhesion since the problem was in holes that stretched from the first time and allowed to air comes out.
This method was good for first two times but third time was the last one))
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