Bladder Tank Description

The Bladder Tank is an essential part of the Bladder Tank Proportioning System.
They require no external power, other than a supply of water to ensure proper operation.
The Vertical and Horizontal Bladder tanks are designed and constructed in accordance with the latest revisions of I.S.P.E.S.L.or ASME code Section VIII for unfired pressure vessels. They have a working pressure of 12 bar (175 PSI) and they are tested to 17,2 bar (249,5 PSI). Used with a ratio controller, this system is designed to inject foam concentrate into a suitable water supply and to automatically proportion foam concentrate over a wide range of flows and pressures.
A flexible hypalon neoprene or polyurethane internal bladder holds the foam concentrate and keeps it from coming into contact with water or the inside of the tank shell. A hydrometer (level indicator) is located in the bottom side of the tank to indicate the level of the foam in the bladder.
The bladder tank is equipped with vent valves, water and concentrate drain/ fill valves, vessel support mounts, discharge pipe and a safety valve to protect it from overpressure.
The center discharge piping, located within the bladder, insures that the foam concentrate flows to the upper discharge.
During operation, water supplied from the system fills the area outside of the bladder, gradually displacing the foam concentrate inside the bladder causing the bladder to collapse until the supply is exhausted. The bladder tank discharges foam concentrate for the remotely mounted ratio controller at approximately the same pressure as the water supply. Since the bladder tank system is pressurized during operation, the bladder can be refilled with concentrate only when system is not in use.

Applications

Frequently used in plants with an only one mixing system have to satisfy different rates flow.
The Sabo Española bladder tanks can be used to proportion aqueous film forming foams (AFFF/ARC), fluoroprotein foams and protein foams. The bladder tank is part of a foam system. In addition to the bladder tank, the main components of the foam system are foam concentrate, the concentrate controller, the water supply, piping, and discharge devices. The most commonly used discharge devices are sprinklers, nozzles, foam chambers, monitors low or medium expansion foam branch pipe, high expansion foam generators.

Features

Compatible with any type of foam concentrate.
Vertical or horizontal type bladder tank can be supplied to satisfy any type of installation.
Technical Specifications
Bladder tanks shall be I.S.P.E.S.L. or ASME code welded pressure vessels constructed of carbon steel with a working pressure of 12 bar (175 PSI).
The circumferential, as well as the longitudinal body seam, shall be machine welded. The tank interior shall be sand blasted white and have all welds and edges ground smooth. The tank shell water inlet will be screened to prevent bladder to blow out or the entrapment of debris between the tank shell and the bladder. All other openings greater than 1” shall be screened to prevent bladder blowout. The vertical tank assembly is supported by four legs providing easy access to the bladder drain/fill valve and the tank shell drain/ fill valve. Four mounting holes are provided for anchoring the tank. The horizontal tank assembly is supported on two saddles welded to the tank and furnished with anchoring holes.
A flexible rubber internal bladder holds the foam concentrate and keeps it from coming into contact with water or the inside of the tank shell. The tank shall have center discharge piping, located within the bladder, to insure that the foam concentrate flows completely to the upper discharge connection. An internally installed iron or stainless steel channel, between bladder and tank shell, shall extend from the water vent to the water drain connection to prevent the bladder from obstructing these openings. Tank shall include all necessary drain and vent valves, concentrate fill piping and filling pump.
External surfaces of tank and piping shall be coated with red high solids epoxy finish with different type of painting cycle.

Ordering information

When ordering SABO Española tanks, it is necessary to provide the following information:
• Type of tank required; Vertical or Horizontal.
• Size of tank.
• Exterior finish of tank.
• Whether required for salt water environment.
• Any other options required.
The Sabo Española sell mainly two types of tanks different only for the equipment accessories supplied.
At the base tank it is possible to add mixer that allows regulating the percentage of the foam in exit from it at the value set in advance. According to the model of the mixer selected the name and consequently the configuration of the tank changes.
The mixers supplied from Sabo Española are mainly of 2 types.
A classic type mixer with calibrates diaphragms called SE-MIX is suitable to the greater part of the firefighting systems.
The mixers can be supplied of various dimensions to second of the selected flow rate capacity; it is different from the models present in the market for elevated precision of regulation joined to a complete absence of maintenance and a lowest value of pressure loss. The standard flow rate range corresponds to relationship of 1 to 6 between the minimum flow rate and the maximum. The second type is normally called SE-WRM; the mixer is completely different from the previous model. The main difference regarding the previous model is the possibility to obtain a wider range of flow rate (in the bigger model it is than 1:100) at disadvantage of the precision of mixing and the pressure loss. The bladder tank with the mixer type SE-MIX, the tank name is transformed generically in SE-MXC-I (or H-I for the horizontal versions) plus the number that indicate the capacity of the tank. Bladder tank with the mixer type SE- WRM the name of the unit become SE-MXC-I (or H-I) – WRM.

Installation

The connection of the tank, whichever is the version, is very simple since there is a water inlet flange and a foam outlet flange, in order to find the position of these connections consult P&I present in this document or consult the installation and maintenance manual.
Sabo Española suggests leaving the bladder tank always under pressure; the main advantage of this choice relapse in the immediacy in the operation of the equipment in addition to smaller possibilities of damaging the bladder tank for malfunction in the system.
In the bladder tank with mixer are present two wafer type ball valves for the exclusion of the tank from the system.
If is adopted the choice to maintain the bladder tank always under pressure, the cut-off valves installed on the body of the mixer must remain constantly open, in this way the equipment is ready to be used and it does not need of ulterior participations. Otherwise we suggest using a remote command valve.
CAUTION: FOLLOW THE FILLING INSTRUCTIONS TO AVOID DAMAGE OF THE BLADDER TANK. DO NOT WELD ON THE TANK, AS HIGH TEMPERATURES CAN DAMAGE THE BLAD DER.
It is the responsibility of the owner or design engineer to provide a primary relief valve to protect the tank from
over pressurization.

Inspection, maintenance and tests

According to the Technical data of teh foma system of SABO Española, consult the instructions for inspections and tests to complete foam system and the installation and maintenance manual.

Availability and service

The Sabo Española bladder tanks are available through a network of domestic and international distributors.
(To find a distributor near you contact Sabo Española Corporation)

Guarantees

For details of warranty, refer to Sabo Española’s current list price schedule or contact Sabo Española directly.