Report - Solicitor, Preston - 27/10/2008

[Bigjobs]

Visited with Over

So, dropping over off at home after a weekend of hijinx , we called over to pay a visit to the Solicitor drain.

What a lovely little culvert it is too, very old in places, with flowstone all over the place. It's just over half a mile long.

Anyway, here's the pics.

Towards the end, there's a pipe cover, which we lifted and made our way down. No, i forgot to get a shot of it.

At the end, is a holding tank for shit. (and I'm allowed to say shit here, cos that's exactly what it is)

With a funny sound coming from it, like a very loud bat, but obv not a bat.

I've taken a video of it, or the sound and uploaded it to youtube, any ideas what it is?

 

[pastybarm]

Great report, the youtube clip is interesting, ultrasound sensor pinging?

 

[FreshFingers]

The time period sounds too long for a transducer type sensor. The pulses are normally in the order of sub-ten millisenconds with almost no reflective return within the audiable range.

They don't half hurt when you put a finger on the transducer face though!

 

[pastybarm]

Cheers FF, stuff like this fascinates me. Seen one by the croal but it makes no noise, amazed it hasn't been nicked to be honest!

 

[pastybarm]

Why do they hurt? Electric?

 

[FreshFingers]

Crudely put, a Piezo electric transducer uses a disc which flexes under a pulse of current sending a focussed 'beam' of pressure waves out from the face. The sensor circuit can determine the distance from the face using time calc's, hence used for measuring water levels, amongst other things like densities. It's the needle-like jet of pressure that stings a bit.

Think of dolphins and submarines clicking and pinging away

 

[pastybarm]

ok, think I got it. So what do you reckon the sound could be in that tank in the vid?

 

[FreshFingers]

Pass, maybe flow of water is making something swing and clatter, the pattern changes slightly a couple of times.

 

[pastybarm]

Yes, I thought it could have been a chain or a flap valve, but it does sound high pitched. Thanks for all the replies.

 

[mingerocket]

Cheers FF, stuff like this fascinates me. Seen one by the croal but it makes no noise, amazed it hasn't been nicked to be honest!

Could be radar or ultrasonic level device. We use similar in the storage tanks at work.

 

[pastybarm]

Thanks, was hoping someone working in the field would comment. To me (but no expert!) it sounds like it is pinging down and then back, but the video is so dark it is hard to see if there is any measurement device on the roof of the tank. Google has not found much for preston and the brook name. Thanks for your reply! A slight edit/update, from looking closely on the left there appears to be a narrow pipe/rod, and from a quick google it seems it could be a radar level sensor, there is also a white thing, but that could be a ball of paper stuck to the side of the tank. Judging from I can see nowt on the ceiling, I am going with it is a radar level sensor on the wall, that goes down into the "water" as a probe, and bounces out a signal across the surface/empty half of the tank, hence the sound. But your reply I think is on the mark, might pm.

 

[pastybarm]

BUMP: I have seen on another website the outfall, cannot find anything like a GRP box above ground for this tank. Presumably this tank acts to stop sewage spills into the Eaves Brook and thus the Savick Brook? Worked out where the brook goes, and there is a mention of plungington sewage works, but not much to see, alas. One of those to look at up close to work it all out.