UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 15
Default Soft close solenoid valve for DIY fox scarer?

I finished making my fox (and cat) scarer using one of those noisy impulse water sprinklers. This is controlled by a PIR which activates a 12v solenoid valve connected to the garden hose that then connects to the sprinkler.

It works a real treat but the problem is that solenoid slams shut instantaneously. This sends a shock wave back through the water system. And the result was that the shock waves caused a water leak at a junction of the incoming water supply from the street.

My question is to find out if there's an easy way to overcome the shock wave problem - either by:-
1. Electrical solution to close the solenoid progressively - whilst still making it open instantly.
or
2. Some mechanical means in a pressure vessel or whatever?

All suggestions are welcome.


  #3   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 2,944
Default Soft close solenoid valve for DIY fox scarer?

On Tue, 23 Oct 2012 11:54:00 +0100
Harry Bloomfield wrote:

presented the following explanation :
I finished making my fox (and cat) scarer using one of those noisy
impulse water sprinklers. This is controlled by a PIR which
activates a 12v solenoid valve connected to the garden hose that
then connects to the sprinkler.


I tested that idea around 20 years ago :-)

I gave the idea up simply because our water pressure was not
sufficient to provide a jet of water quickly enough on the opening of
the solenoid.

One solution to the shock, might be to T in a length of hose pipe
between solenoid and water supply. If the new length of pipe were
maintained full of air, then because the air is and the hose are
compressible, it would act as a buffer to the shock.


That is a perfectly sound idea, used in industry as well as some
domestic situations. I have seen it in a basement at the utility sink. I
once had the same problem with a four-inch water supply pipe, which
descended vertically from a plant ceiling for more than 40 feet before
meeting a solenoid valve. The resulting shock made the pipe's
horizontal run, before the change to the vertical, move a foot sideways
at its worst. We tried these shock absorbers, but they weren't man
enough for this job.
It was fixed by installing a slow stepping valve, at the top of
the vertical drop, which was slow enough to gradually control the
water flowrate.
Getting up to the valve was an experience in itself.
--
Davey.
  #5   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 3,703
Default Soft close solenoid valve for DIY fox scarer?

In article ,
writes
I finished making my fox (and cat) scarer using one of those noisy impulse water
sprinklers. This is controlled by a PIR which activates a 12v solenoid valve
connected to the garden hose that then connects to the sprinkler.

It works a real treat but the problem is that solenoid slams shut instantaneously.
This sends a shock wave back through the water system. And the result was that
the shock waves caused a water leak at a junction of the incoming water supply
from the street.

If, as you say, the shock is causing a leak in your domestic supply
pipework (not your hose or hose fittings) then your pipework or that of
your supplier is faulty. Solution, fix it, or have them fix theirs.

My question is to find out if there's an easy way to overcome the shock wave
problem - either by:-
1. Electrical solution to close the solenoid progressively - whilst still making it
open instantly.
or
2. Some mechanical means in a pressure vessel or whatever?

All suggestions are welcome.

If you are talking about the shock affecting the hose fittings then the
following may help:

By nature, solenoids are bangy, they operate with more and more force as
they close so it is an inherent problem. You can get slow close solenoid
operated valves for irrigation but they are a bit slow in operation so I
doubt they would be suitable.

You can get shock arrestor capsules (similar to expansion vessels) for
use on water systems. See water hammer arrester half way down this page:

http://www.bes.co.uk/products/109.asp

The inverted pipe idea wont work long term as the air will be
re-absorbed by water under pressure.
--
fred
it's a ba-na-na . . . .


  #6   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 9,560
Default Soft close solenoid valve for DIY fox scarer?

On Tuesday, October 23, 2012 11:28:40 AM UTC+1, wrote:
I finished making my fox (and cat) scarer using one of those noisy impulse water sprinklers. This is controlled by a PIR which activates a 12v solenoid valve connected to the garden hose that then connects to the sprinkler..



It works a real treat but the problem is that solenoid slams shut instantaneously. This sends a shock wave back through the water system. And the result was that the shock waves caused a water leak at a junction of the incoming water supply from the street.



My question is to find out if there's an easy way to overcome the shock wave problem - either by:-

1. Electrical solution to close the solenoid progressively - whilst still making it open instantly.

or

2. Some mechanical means in a pressure vessel or whatever?



All suggestions are welcome.


Oil the solenoid. Try 20/50 first.


NT
  #7   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 9,066
Default Soft close solenoid valve for DIY fox scarer?

On Oct 23, 11:28*am, wrote:
I finished making my fox (and cat) scarer using one of those noisy impulse water sprinklers. This is controlled by a PIR which *activates a 12v solenoid valve connected to the garden hose that then connects to the sprinkler.

It works a real treat but the problem is that *solenoid slams shut instantaneously. This sends a shock wave back through the water system. And the result was that the shock waves caused a water leak at a junction of the incoming water supply from the street.

My question is to find out if there's an easy way to overcome the shock wave problem - either by:-
1. Electrical solution to close the solenoid progressively *- whilst still making it open instantly.
or
2. Some mechanical means in a pressure vessel or whatever?

All suggestions are welcome.


http://en.wikipedia.org/wiki/Water_h...ating_measures
  #9   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,460
Default Soft close solenoid valve for DIY fox scarer?

On Tuesday, October 23, 2012 11:28:40 AM UTC+1, wrote:

You can get slow-closing solenoid valve for this application.

You could also use a solenoid valvle as a pilot valve operating a diaphragm valve, with a restriction in the diaphragm discharge; I can't recall how that's done now. Many large 'solenoid' valves are pilot operated diaphragm valves.

Plan B, get a motorized ball valve; less likely the stick open than a solenoid.

  #10   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 746
Default Soft close solenoid valve for DIY fox scarer?

Onetap wrote:
On Tuesday, October 23, 2012 11:28:40 AM UTC+1,
wrote:

You can get slow-closing solenoid valve for this application.

You could also use a solenoid valvle as a pilot valve operating a
diaphragm valve, with a restriction in the diaphragm discharge; I
can't recall how that's done now. Many large 'solenoid' valves are
pilot operated diaphragm valves.

Plan B, get a motorized ball valve; less likely the stick open than
a solenoid.


Make sure it can handle the pressure.


  #11   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 535
Default Soft close solenoid valve for DIY fox scarer?


It works a real treat but the problem is that solenoid slams shut
instantaneously.
This sends a shock wave back through the water system. And the result was
that
the shock waves caused a water leak at a junction of the incoming water
supply from the street.



As others have said, if the water hammer is enough to separate a joint to
the main pipe in the street, then it should have blown the hozelok fittings
off the hose feeding the solenoid as well or before the street joint failed,

same if the hose was jubilee clipped on etc, so basically the street joint
was about to give way anyway, could have happened next time you flushed the
bog and it's valve shut off abruptly, or you closed the kitchen tap fast
enough, or the washing machine/dish washer's solenoid did the exact same
thing the fox scarer's solenoid does.

I bought a cat/fox/dog/pikey sprayer from maplins for £14 a few months ago,
runs on 4 x AA's,
Comprises of a spike, an infrared detector and an impulse sprinkler head...
all plastic of course, so a 6 volt solenoid inside it,

Simple to use, push the spike in the ground, put in the batteries, connect
the hose pipe to the hozelok connection on the side, set up the sensitivity
of the detector to cover the area you want to spray, then adjust how far
round the sprinkler works in the 'dut-dut-dut-dut' phase before hitting the
trip to make it go 'zzyyyppppp' back to the beginning,

Then call the Gf out of the house so she walks in front of it and tests it
for you

I've had it on the front garden for about 4 months now, batteries are still
fine in it, but the bloody cat that ****s on the lawn still hasnt learnt, it
gets a soaking every couple of days, so after i take it in for winter, i'll
prolly cannibalize it and make an automatic dog waterer (replacing the
sprinkler head with a hose that lets the water out gently for her to drink
when she approaches... save her begging for someone to turn the wall tap on
for her all the time in summer... hopefully.

  #12   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 2,461
Default Soft close solenoid valve for DIY fox scarer?

On Tue, 23 Oct 2012 20:21:58 +0100, "Doctor Drivel"
wrote:

Insert a T-piece with a blanked vertical pipe from it of around a foot
length of 1" pipe. Leave it filled with air. It will act as a shock
absorber.


Until the air dissolves.


So put a Schraeder valve on top.
  #13   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,460
Default Soft close solenoid valve for DIY fox scarer?

On Wednesday, October 24, 2012 11:58:28 AM UTC+1, Gazz wrote:

As others have said, if the water hammer is enough to separate a joint to

the main pipe in the street, then it should have blown the hozelok fittings

off the hose feeding the solenoid as well or before the street joint failed,


The others is wrong.

You can get a huge shock pressure from water hammer. There have been many accidents where water hammer has smashed steel pipe fittings, usually slugs of condensate on starting a steam main from cold.

It's how a hydraulic ram works.
  #14   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 746
Default Soft close solenoid valve for DIY fox scarer?

Grimly Curmudgeon wrote:
On Tue, 23 Oct 2012 20:21:58 +0100, "Doctor Drivel"
wrote:

Insert a T-piece with a blanked vertical pipe from it of around a
foot length of 1" pipe. Leave it filled with air. It will act as a
shock absorber.


Until the air dissolves.


So put a Schraeder valve on top.


Oh my God, he wants to pump it up every few weeks.
  #15   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 5,175
Default Soft close solenoid valve for DIY fox scarer?

On Wednesday, 24 October 2012 12:34:22 UTC+1, Onetap wrote:
It's how a hydraulic ram works.


No, if you have water hammer, your hydraulic ram stops working. An effective ram relies on the air spring, and in getting nearly all the energy of the ram into that air spring, from where it can then be usefully made use of. All water hammer does is to make your valves bounce.

(And unlike you, I've built rams, and they worked)


  #16   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 2,461
Default Soft close solenoid valve for DIY fox scarer?

On Wed, 24 Oct 2012 18:01:24 +0100, "Doctor Drivel"
wrote:

So put a Schraeder valve on top.


Oh my God, he wants to pump it up every few weeks.


Well, you have to do something to while away the idle hours. You could
draw on your experience with pump-up penile insertions.
  #17   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 2,461
Default Soft close solenoid valve for DIY fox scarer?

On Sun, 28 Oct 2012 19:45:15 -0000, "Doctor Drivel"
wrote:

How does your work?


And again, in Engilsh?
  #18   Report Post  
Posted to uk.d-i-y
external usenet poster
 
Posts: 1,460
Default Soft close solenoid valve for DIY fox scarer?

On Wednesday, October 24, 2012 9:50:53 PM UTC+1, Andy Dingley wrote:

No, if you have water hammer, your hydraulic ram stops working. An effective ram relies on the air spring, and in getting nearly all the energy of the ram into that air spring, from where it can then be usefully made use of.. All water hammer does is to make your valves bounce.



(And unlike you, I've built rams, and they worked)


How does it generate a higher pressure pulse than the pressure of the water stream?

By bringing the water stream to a sudden halt and converting the kinetic energy into pressure.

And what is this effect called?

Water hammer. http://en.wikipedia.org/wiki/Water_hammer#Applications

"The water hammer principle can be used to create a simple water pump called a hydraulic ram."

http://en.wikipedia.org/wiki/Hydraulic_ram

"The device uses the water hammer effect to develop pressure that allows a portion
of the input water that powers the pump to be lifted to a point higher than where the water originally started."

Unlike you I am neither a patronizing dullard nor wrong.

I shall expect your apology shortly after you grow a spine.


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Soft close damper (Hafele) Charles C UK diy 2 October 24th 10 08:56 PM
Soft Close Hinges Thomas UK diy 7 July 23rd 09 12:42 AM
Soft Close Toilet Seat? No Name UK diy 0 May 3rd 09 06:48 PM
soft close toilet seat [email protected] UK diy 2 March 10th 09 09:03 PM
"soft-close" drawer glides George Beshers Woodworking 6 January 16th 05 04:40 AM


All times are GMT +1. The time now is 08:07 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"