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மழை நீர் சேகரிப்பு தொட்டி

October 23rd, 2010 No comments

நான் இருக்கும் அடுக்கத்தில் தண்ணீர் தட்டுபாடு வெயில் காலங்களில் அதிகம், பல நூறு ரூபாய்கள் கொடுத்துதான் தண்ணீர் வாங்கவேண்டியிருக்கும். கடந்த ஆண்டு ஒரு தொட்டி (சுமார் 10000லி) தண்ணீருக்கு ரூ 750 வரை கொடுத்து கொள்முதல் செய்தோம். சக குடியிருப்போர், என்னுடைய உந்துதலின் பெயரில் மழை நீர் சேகரிப்பு செய்ய ஒப்புதல் மற்றும் உபயமும் செய்தனர். என்னுடைய தொட்டியில் வரைபடத்தை இங்கு தொகுத்துள்ளேன்.

முயற்சி #1

சுமார் 4000 ரூபாய் செலவில் அமைத்த தொட்டி கீழே கொடுக்கப்பட்டுள்ளது. இந்த திட்டத்தில் நன்மைகளும், தீமைகளும் இருந்தன. நன்மையெனில், செலவு குறைவு, திட்டப்பணி வேகமாக முடிக்கமுடிந்தது, தண்ணீர் சுத்தமாக வந்தது; தீமைகளெனில், பராமரிப்பு கடினம், compressor motor உடன் ஒத்துபோகவில்லை (மணற்படுகை பிரண்டது), தண்ணீர் வேகம் குறைவு.

முயற்சி #2

சுமார் 8000 ரூபாய் செலவில் அமைத்த தொட்டி கீழே கொடுக்கப்பட்டுள்ளது. இந்த திட்டத்தில் நன்மைகள் மட்டுமே இருந்தன. முதல் திட்டத்தின் தீமைகள்யாவும் களையப்பட்டன. செலவு மட்டும் இரண்டு மடங்கு ஆனது, இருந்தாலும் பராமரிப்பு சுலபம், கப்பிரஸர் மோட்டாருடன் ஒத்துபோதல், தண்ணீரின் வேகம் அதிகமாக இருப்பதால் செலவு பெரதாகத் தெரியவில்லை.

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Timer Controller for our apartment water pump..

March 29th, 2009 14 comments
We have a 1.5HP compressor pump for pumping water from 350 feet deep to a 100 feet over head tank.  Since, we have water scarcity through out the year, we run the pump following a timing.  Typically in 24 hours, the pump runs for 6 hours in 1 hour slots spaced by 3 hours for water to accumulate in the borewell.

We have assigned the task of switching on and off the water pump to our security guards.  They are doing a good job in keep the pumps up and running, but sometime they either overrun or underrun the pumps.  Being the technical adviser of the apartment, I had decided to replace the security guards to an automatic timer controller.

I did some investigation about timer controllers via Internet and yellow pages but I was not very successful in finding a single stop solution.  There are many vendor who provide water level controllers, but not the timer controller.  So, I decided to go to Parry’s corner in search of an expert who can do the task for me.  I found a vendor in Thambu Chetty street who gave me the contact phone of a person who does erection of pump controllers.  I called the guy and he said he does not handle timer controller, but definitely give me a call back after consulting with his group.

I continued by search in the street and ended at “Switchgears India”, 149/2 Thambu Chetty Street, Chennai 1 and enquired about timer controllers.  He immediately showed me a product which he claimed to be useful for industrial timed switching purposes.  The guy should be Rajesh Bhandari (9840133670).  He showed me the product named “Frontier Timer TM-619H-2”, which had 8 On and Off timers.  There was another engineer who was sitting there helped me in configuring the timer.  When I tried setting the times, I found it very versatile and immediately useful.  They priced this product at Rs 600 without bill or warranty.  The shopkeeper promised that the product is doing well and he had sold over 1000 pieces.  This product also comes with an internal battery for keeping up with the LCD display and clock feature.

The product showed that it can switch on a 2HP motor directly, which I did not believe.  I guess the internal switching is by a TRIAC semiconductor which may burn out if connected directly to an Inductive load like water pump motor.   The shop keeper insisted me to get a Contactor which is typically a Electro Magnetic Relay to do the switching of the pump.  I asked him to offer a product and he gave me a contactor namely “IDEAL ID1-22 1a1b AC220V 50Hz”, which by the spec should be able to switch even a 5 HP motor.

The contactor that he gave is 3 phase relay, which I could use for a single phase motor.  I connected the L1 to supply and T1 to the motor with neutral short directly; L1 and T1 are in N/O connection.  Similarly the contactor had L2 -> T2 and L3 -> T3 for 3 phase switching. I connected the A1 and A2 of the contactor to the Output of the Timer.  The input of the Timer is connected to LIVE supply.  The contactor also provides a N/C connection which I did not use.

I programmed the timer for 6 time slots and connected the supply and load to the contactor.  It works super cool.

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Compressor Vs Jet Pumps

July 17th, 2008 8 comments

Most of us are not aware of a type of domestic water pump called the Compressor pump. I had come across this noisy pump a couple of year ago. The operation of this pump is very simple and powerful though it is noisy. The pump consist of a Air Compressor and a nozzle. See that’s all. Remember in jet pumps we would have an Impellor and a Jet (a form of nozzle). Compressor jumps compresses atmospheric air and pressurized that thru the nozzle which creates a back pressure to pull water for far depths to the surface and above. The advantage is that the compressor (motor + compressor) is no way connected to water drawing system other that at the nozzle. Whereas in jet pumps water is drawn by the back pressure created at the impeller’s center (radial flow) which makes it apparent that water is always in touch with the motor + impeller system. In jet pumps there are two pipes down to the water level one for drawing and one of recycling. Jet pumps push a portion of drawn water downwards to create back pressure at the jet-nozzle. Water flows from bottom to impeller, impeller to top, impeller to bottom again. In compressor pumps, the since air is pushed downwards water flows only from bottom to top.

In a compressor pump, the flow of water does not start immediately because the water starts flowing only after a certain amount of pressure is built at the nozzle. Also the flow of water is not uniform typically the pump pushes gush of water in regular intervals of time at like a jittery saw tooth waveform. Since a compressor is needed, these pumps are noisy. In a Jet pump, the water flow is more or less uniform and the water pumping starts immediately once the pump is switched on. Here water level is maintained in the delivery pipes and also at the impellor system. Jet pumps are almost quite when all the bearings and move parts are properly lubricated.Disadvantages are found in both systems. In a jet pump, water is always expected to be maintained at the impellor system. The water level is maintained by a spring driven valve at the jet below water level. During the passage of time, this spring and valve gets damaged which is defy the requirement of impeller water level. So one has to fill in water everytime to start the pumping action. Jet pumps dont work at all when there is a lot of slime around the jet or if the valve is stuck due to any particles near it.

In a compressor pump, if there is a leak in the downstream air flow, water pumping does not happen as the pressure could not built at the nozzle. When the strength of the compressor falls below a threshold again the water pumping stops for the same reason. These pumps are very noisy (both reciprocating and centrifugal). The pumps needs regular maintainance as they have more mechanical moving parts (basically the compressor oil needs to changed on a regular interval). Also, upstream water flow should not be blocked completely which would affect the nozzle, so it is not possible to close the gate valve in the upstream when the pump is running. Whereas the upstream
of jet pump can be completely shut even when the motor is running.

Compressor pumps are more suitable for borewells with depths of range 200+ feet. Jet pumps are more suitable for wells and sumps. Compressor pumps can work even when there are dirt or dust in the water as the pressure at the nozzle would push them away from blocking the channel. Jet pumps are good when the nozzles are suspendable well above the surface level in the well. In the case of bore well, jet pumps are fine if casing is done for the entire depth. Compressor pumps are atleast 1.2 times expensive than Jet pumps in Chennai.In general when you go for deeper borewell, it is always adviced to go for pvc continuous hose pipes instead of discrete pipes with joints. It serves two purposes. 1) Maintenance is easy as it would relatively very easy to take out the entire hose out of the bore as you can roll it. 2) Two many joints in the upstream/downstream deteriotes the performance of the pump.