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Bladder Expansion Tank

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Application
An expansion tank is used in a hydronic (heating/cooling) system to accomplish three main tasks: (1) accommodate thermal expansion of the fluid, (2) maintain positive pressure at all points in the system at all times, (3) maintain net positive suction head at the chilled water pump(s). 
In addition to perform the 3 tasks, the bladder expansion tanks provide extra benefit of complete separation of fluid from air, which eliminates absorption of air into the system and water logging. It also helps preventing air bound terminal units, excessive corrosion, inefficient balancing and pump cavitation over the life of the system.
Description 
The closed bladder expansion tank consists of a cylindrical casing made by carbon steel with a rubber bladder inside. System fluid is connected with the bladder inner chamber via the flange at the casing bottom. The chamber between the casing and bladder is pre-charged with Nitrogen as air cushion. Fluid is contained inside the bladder without contacting casing. The air cushion accommodates the fluid volume changing inside bladder during expansion and contraction as system fluid temperature changes. 
The bladder expansion tanks are designed to absorb the expansion forces resulting from the changes in temperature of the heating/cooling fluid in hydronic heating/cooling systems, to maintain the proper system pressurization. 
As the system fluid expands, it is forced into the rubber bladder of the pre-pressurized tank to the higher system pressure. The pre-charged air cushion then forces the fluid back from the bladder into the system as it contracts. The rubber bladder is fixed within the casing by flanges at top and/or bottom. It is replaceable easily by removing the flange(s). A pressure gauge is installed on the casing for monitoring working pressure. A charging port is provided on the casing for easier adding air into tank whenever necessary.   
Working Principle

Original status:

The bladder is filled with liquid at same pressure as nitrogen inside casing, not deformed.

 Contraction status:

Liquid inside bladder is under less pressure when system total liquid volume is less as temperature lower. The bladder is compressed by nitrogen to feed liquid back to system.

 Expansion status:

The bladder is expanded when liquid pressure inside is higher than nitrogen, when system total liquid volume is more as temperature higher.  The bladder is expanded by liquid and absorb the extra liquid volume from the system.

★However, bladder expansion will be avoided by selecting models with sufficient capacity, even bladder allows deforming at a certain level. Over-expansion is the main reason for bladder broken.

 

Features 

◇ Replaceable rubber bladder.

◇ Pre-pressurized by Nitrogen.

◇ Pressure gauge on casing.

◇ Air charging port on casing.

◇ Complete separation of air from water.

◇ Standard: GB 150-1998 (Steel Pressure Vessels), 2014/68/EU

◇ Permissible operating temperature: 70 °C

◇ Max. permissible system temperature 120 °C

 

Specification 
ModelTotal  

Capacity (L)

Adjustable  Capacity (L)Dimension (mm)
DiameterTotal HeightConnection Size
G110100544001260DN50
G3503501256002000DN50
G8008003508002340DN50
G1300130050010002420DN50
G2200220075012002800DN50
G31003100100014002970DN50
G42004200195016003050DN80
G55005500212018003170DN80
G70007000365020003320DN80
Detailed Images

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ORDERING INFO

Particular information:  
1. Total capacity.
2. Adjustable capacity. If not sure, please provide: total water volume in the system, highest and lowest possible temperature.
3. Working pressure.
★ Selection shall be base on adjustable capacity with sufficient redundant capacity,  ensure that bladder won't be expanded (deformed) which is the main reason of broken.  
General information for ordering:

1. Quantity of each size.

2. Delivery location, and price term: EXW, FOB, CIF, DDU, DDP, etc.

3. Detailed information of the contact person and buyer's company, which is helpful to prioritize your inquiry with faster response and better price. 

SHIPPING

Delivery Options:

Delivery Method
Incoterms Term
Applicable Countries
LCL, FCL by sea
EXW, FOB, CFR, CIF
General for all countries.
Air courier to door
DDU, DDP
General for all countries.
Air cargo to airport
CIF
General for all countries.
Door to door by road
DDP
Cambodia, Laos, Myanmar, Thailand, Vietnam. (keep expanding to more countries)
Door to door by seaDDU, DDPCambodia, Indonesia, Malaysia, New Zealand, Philippines, Singapore, Thailand, United Arab Emirates, United Kingdom, United States.   (keep expanding to more countries)
LCL=Less than Container Load.     FCL =Full Container Load
DDU = Delivery Duty Unpaid        DDP = Delivery Duty Paid
The above shipping information is general, and changing from time to time. Confirmation with us is necessary for each order.

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