Surge Vessel
2
TECHNICAL SPECIFICATION Quality Assurance ID No. : SPT 0253-02 GB TITLE: HYDROPNEUMATIC SURGE VESSELS (COMPRESSOR/BLADDER VESSELS) Page 1 of 2 CHARLATTE RESERVOIRS 17, rue Paul Bert 89400 MIGENNES France Tél. : 03.86.92.30.00 Fax : 03.86.92.30.01 E-mail : [email protected] Site : www.charlatte.fr 1. PHILOSOPHY a) Compressor vessels Compressor vessels have been in operation for many years all over the world as a solution to surge problems. The system comprises of a vessel containing water and a pre-calculated volume of compressed air in order to give the required elasticity to push the water at the required rate into the system. To achieve this balance, a complicated system of control is required. Starting with compressors, air receiver, solenoid valves, measuring equipment and of course a control panel. As the air is continuously dissolved into the water, so the control system is activated to replenish the compressed air volume in order to maintain the required elasticity. A number of security systems are also required in the event of system failure. b) Bladder vessels A bladder surge vessel has the same mission with regard to surge control as the traditional compressor vessel. The objective of this pneumatic solution is to simplify the method of regulation. In a similar way to a vessel controlled by compressors, a pre-charge pressure is calculated to give the required elasticity to push the water into the system following a pump shut down or power cut. The major difference being that the liquid is contained within a rubber bladder (compatible with drinking water). Therefore, as there is no contact between the compressed air and the water there is no dissolution. There is thus no requirement for a permanent regulation system including compressors, etc... Once the vessel has been commissioned and the correct precharge has been introduced, the vessel will operate automatically emptying when called upon and refilling with the return waves until naturally refinding its steady state balance.
Transcript of Surge Vessel
TECHNICAL SPECIFICATION Quality AssuranceID No. :SPT 0253-02 GB
TITLE:HYDROPNEUMATIC SURGE VESSELS
(COMPRESSOR/BLADDER VESSELS)Page 1 of 2
CHARLATTE RESERVOIRS 17, rue Paul Bert 89400 MIGENNES FranceTél. : 03.86.92.30.00 Fax : 03.86.92.30.01
E-mail : [email protected] Site : www.charlatte.fr
1. PHILOSOPHY
a) Compressor vessels
Compressor vessels have been in operation for many years all over the world as a solution tosurge problems.
The system comprises of a vessel containing water and a pre-calculated volume of compressedair in order to give the required elasticity to push the water at the required rate into thesystem.
To achieve this balance, a complicated system of control is required. Starting withcompressors, air receiver, solenoid valves, measuring equipment and of course a control panel.
As the air is continuously dissolved into the water, so the control system is activated toreplenish the compressed air volume in order to maintain the required elasticity.
A number of security systems are also required in the event of system failure.
b) Bladder vessels
A bladder surge vessel has the same mission with regard to surge control as the traditionalcompressor vessel.
The objective of this pneumatic solution is to simplify the method of regulation.
In a similar way to a vessel controlled by compressors, a pre-charge pressure is calculated togive the required elasticity to push the water into the system following a pump shut down orpower cut.
The major difference being that the liquid is contained within a rubber bladder (compatiblewith drinking water). Therefore, as there is no contact between the compressed air and thewater there is no dissolution. There is thus no requirement for a permanent regulation systemincluding compressors, etc...
Once the vessel has been commissioned and the correct precharge has been introduced, the vesselwill operate automatically emptying when called upon and refilling with the return waves untilnaturally refinding its steady state balance.
TECHNICAL SPECIFICATION Quality AssuranceID No. :SPT 0253-02 GB
TITLE:HYDROPNEUMATIC SURGE VESSELS
(COMPRESSOR/BLADDER VESSELS)Page 2 of 2
CHARLATTE RESERVOIRS 17, rue Paul Bert 89400 MIGENNES FranceTél. : 03.86.92.30.00 Fax : 03.86.92.30.01
E-mail : [email protected] Site : www.charlatte.fr
2. PROS AND CONS
a) Maintenance
It is evident that one of the major advantages of the bladder system is the need for minimummaintenance. Once commissioned a three monthly check is recommended to ensure that thenecessary pre-charge pressure is still in place. If any adjustment is required a portablecompressor will suffice.
The traditional compressor system will on the other hand require constant maintenance toensure that the system is properly protected, and in the case of power failure will requireadditional generator facilities to operate the compressors.
Other than the human and financial cost impact which may or may not be a problem, inremote areas away from inhabited areas, i.e. booster stations, etc... the problems arecompounded.
b) Air/water contact
In vessels controlled by compressors, there is permanent dissolution of air into the water. Notonly does this call for the control systems that have to be installed to replenish this air, but it isevident that this air will eventually reappear elsewhere in the system.
With the bladder system, there is no contact between the air and water, this problem does notexist.
c) Corrosion
Due to the permanent contact between the water and the walls of the vessel an effective coatingsystem is required as well as an extra corrosion allowance, depending on manufacturing code,which can be over 3 mm. This can obviously be a costly exercise depending on volumes andservice pressures.
In the case of the bladder vessel this problem is negligeable, as there is no contact between theliquid and the vessel, other than the humidity contained in the compressed air, which requiresa minimal internal protection. This problem can also be completely overcome by the use ofnitrogen instead of compressed air in the bladder. An option which is not possible in acompressor vessel due to the gas/liquid contact.
3 CONCLUSION
CHARLATTE RESERVOIRS have been manufacturing bladder vessels for around 30 years.We have installed these vessels whether for surge or supression solutions throughout the worldon all the major continents.
We have large bladder vessels up to 75000 litres in operation in Europe and in countries such asEgypt, Saudi Arabia, United Arab Emirates, Libya, etc... and whilst no one would deny thatcompressor vessels are a viable technical solution for surge protection for sheer practicality andease of operation more and more operators are choosing a bladder vessel solution.
