Balancing Valves

Document Sample
Balancing Valves Powered By Docstoc
					BENEFITS OF USING DYNAMIC BALANCING VALVES
Dynamic Balancing system makes easy of starting up the system and also give many
advantages for installation and operation

A good system that is controlled according to inner conditions needs a balanced HVAC
system. According to this, every heating and cooling device should take the needed water
flow for realizing the right heat transfer.

The preferable system balancing method in England is putting twice regulation valves to
pump return pipe, riser connections, branch points and terminal devices. And also this system
needs a supervisor for balancing as proportional.

Proportional balancing is a demanding work that needs many settings and supervisor services
for the right water flow rates as every valve. Also this work needs much times. But dynamic
balancing simplifies starting up the system and provides many advantages.

Dynamic balancing valves work automatically and set its flow coefficient (variable Kv
values) automatically, too. Flow limiters are well-known of dynamic balancing valves. They
are used with cartridges that are set before now or external adjustable scale. All flow limiters
have constant Kv values until the beginning flow value reaches the stated value. At the same
time, the flow rate at the valve installation circuit, are set to the maximum value. If pump
head at the valve are located in the valve’s working areas and the flow limiter works
normally, the design flows are saved.



Easy Start-up

There are so many advantages of using Dynamic Balancing Valves at HVAC systems. The
most important one is removing the proportional balancing necessity.

If variable speed pumps are used in the system, pump period is decreased while starting up
and also differential pressure value at the beginning valve has been bigger than the starting up
value. All other valves are sit down under the bigger pump pressure and all has worked as
limiting the flow rate at the certain maximum value. After this time, system is totally balanced
and there is no need for having a proportional balancing. Also it doesn’t need more flow
limiter valve. All flow limiter valves are removed from the branches, risers and pumps.
Verifying the flow as being the part of starting up, digital manometer can be used as reading.



STATIC AND DYNAMIC TYPE BALANCING VALVES USAGE
Static balancing valves that are used at certain points are set according to the Project values
and also provide the right distribution of the required flow. According to the valve size, the
measuring precision of variable orifice static type balancing valves as the setting position is ±
%10. Also dynamic balancing valves should be used as setting the certain and required flow
values before now. The measuring precision is approx. ± %5. As it can be seen clearly from
the below diagram, the flow rate will change during the red curve because of the difference of
pressure as increasing and decreasing. While the setting, it will be a constant orifice area
because of being a globe valve and then the flow rate will change. But at the dynamic
balancing valves, there is a moving orifice area and it prevents to change the flow during the
blue curve till the above one.




APPLICATION FOR SHOPPING MALLS
At the shopping mall projects, it is certainly advised that dynamic type balancing valves are
more beneficial than static type balancing valves. Especially shell and core type projects if
static type balancing valves are used, it needs to have many supervisor services for the
starting up. Because all shops are not opened at the same time and at every shop opening, the
system needs to have balanced not only the opening area. It means also many supervisor
services. Also the service personnel set the project values at the entrance of the shop, but
some times later there will be flow changes at the shop because of its inner devices. However,
if dynamic balancing valves are used at these kinds of projects, valves are set to the project
values and there is no need to start up for every time. It means that there hasn’t got supervisor
cost for every time.

				
DOCUMENT INFO
Shared By:
Stats:
views:26
posted:2/27/2012
language:English
pages:3
Description: Documents shows the differences between static and dynamic balancing valves