Hydro Tanks

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hydro pnematic tanks

Text of Hydro Tanks

  • PRESENTATION

    ON

    HYDROPNEUMATIC TANKSBY

    JAMES E. PANDOLPH, P.E.

    TEAM

    ANKNGINEERING

    NDANAGEMENT

    CONSULTANTS, INC.

  • WATER STORAGE TANKS

    ARE CRITICAL TO THE EFFICIENT OPERATION OF ANY WATER DISTRIBUTION SYSTEM

  • PURPOSE OF STORAGE

    VOLUME

    PRESSURE

  • TYPES OF STORAGE

    PROVIDE LARGE VOLUMES OF WATER, USUALLY FOR LARGER WATER SYSTEMS

    GROUND STORAGE TANKS OR RESERVOIRS

    DO NOT PROVIDE PRESSURE TO THE SYSTEM UNLESS:

    1. BUILT ON A HILL

    2. PUMPED TO AN ELEVATED TANK.3. USE OF HIGH SERVICE PUMPS TO PROVIDE

    PRESSURE TO THE SYSTEM

  • INSERT A GROUND STORAGE TANK HERE ST. PETE OBERLY

  • TYPES OF STORAGE

    ESSENTIALLY A GROUND STORAGE TANK WHOSE HEIGHT WILL PROVIDE ADEQUATE SYSTEM PRESSURE.

    STAND PIPES

    ONLY UPPER VOLUMES ARE AVAILABLE TO PROVIDE ADEQUATE PRESSURE

    1. CAREFULL CIRCULATION IS REQUIRED TO PREVENT STAGNATION, STRATIFICATION & OTHER PROBLEMS.

    2. PROPER SOIL BEARING IS MANDATORY.

  • ELEVATED STORAGE TANKS

    HEAD RANGE (HR)

    HT. TO LCL

    HT. TO HCL

    HCL ESTABLISHES MAX PRESSURE

    HR CONTROLS Pressure variation

    LCL ESTABLISHES MIN PRESSURE

  • ELEVATED STORAGE TANKS

  • ELEVATED STORAGE TANKS

  • HYDROPNEUMATIC TANKS

    Hydropneumatic tanks (or pressure tanks) are very common in small water systems that use wells to supply drinking water. The hydropneumatic system combines the energy from a pump (usually the well pump) with the principle of air pressure to force water into the distribution system. These tanks are installed between the well pump and distribution system and are intended to:

  • Maintain an adequate and relatively even pressure in the distribution system

    Reduce the number of times the well pump turns on and off

  • Hydropneumatic tanks are usually not large enough to provide sufficient water storage for fire fighting. Availability of alternate water sources must be considered when selecting a hydropneumatic system for a municipal supply.

    Because the volume of stored water is minimal, operational failures that occur with hydropneumatic tank systems can result in the water system customers being completely out of water within a matter of minutes. It is therefore important for all operators of these systems to be familiar with basic troubleshooting steps to identify andcorrect problems with the water system.

  • Types of Hydropneumatic Tanks While the number and size of hydropneumatic tanks

    may vary widely from system to system, there are four basic styles of tanks. Depending on the type and size, these tanks can be installed vertically or horizontally. The general differences between the four styles (shown below) involve the method of separating the air and the water inside the tank. Operators should be familiar with the type of tank(s) in their system.

  • TYPICAL HYDROPNEUMATIC TANKConventional tank WITH AIR COMPRESSOR

    The air cushion is in direct contact with the water. Because air can dissolve in the water, an air volume controller is necessary as well as an air compressor system

    WATER

    AIR

  • MAJOR COMPONENTS OF A HYDROPNEUMATIC TANK SYSTEM

    PURPOSECOMPONENTThe Well and pump. Includes Check Valve, Air relief & Meter.

    Water Source1

    Supports the tank and insures that the tank will not tip over and break a main water supply line.

    Tank Foundation

    3

    Regulates air volume in tank (controls compressor)

    Air Volume Controller

    4

    Stores water and air. Pressurized vessel. Florida requires periodic cleaning & Inspection.

    Steel Tank2

  • MAJOR COMPONENTS OF A HYDROPNEUMATIC TANK SYSTEM

    PURPOSECOMPONENTSupplies air to the tank to maintain air cushion. Unit should be oil free type or be fitted with filters to prevent oil from entering the water.

    Air Compressor5

    Prevents excessively high pressure in the tank. Generally 100 psi maximum.

    Pressure Relief Valve

    6

    Allows flow of water in and out of tank. Both should be fitted with gate valves and inlet pipe should be fitted with a check valve.

    Inlet/Outlet Piping

    7

  • MAJOR COMPONENTS OF A HYDROPNEUMATIC TANK SYSTEM

    PURPOSECOMPONENTAllows direct observation of air-to-water ratio. Generally the ratio should be 1 to 2, i.e.: 1/3 air to 2/3 water.

    Sight Glass (Tube)

    8

    For monitoring pressure inside the tank and on the distribution system.

    Pressure Gauges

    9

    Controls cut-in (start) and cut-out (stop) cycles of the well pump.

    Pump/Motor Controls

    10

  • MAJOR COMPONENTS OF A HYDROPNEUMATIC TANK SYSTEM

    PURPOSECOMPONENTRegulates the pump/motor controls based on pre-set cut-in and cut-out points. These are adjustable but adjustments should be performed only by qualified personnel. The settings should generally provide a minimum of 40 psi and a maximum of 70 psi throughout the distribution system. The pressure should never be allowed to drop to below 20 psi. Alarms should be provided to notify the operator in the event of a system failure (low water pressure)

    High/Low Pressure Controls

    11

  • MAJOR COMPONENTS OF A HYDROPNEUMATIC TANK SYSTEM

    PURPOSECOMPONENTRegulates water level in the tank.High/Low Water

    Level Controls12

    Measures quantity of water pumped.

    Master Water Flow Meter

    13

    Records total hours of water supply pump operation.

    Elapsed Time Meter

    15

    Records number of pump cycles. Should be limited to a maximum of 10-15 cycles per hour. Cycles can adjusted by high/low pressure controls.

    Cycle Counter14

  • 2/3 water

    1/3 air

    Foundations

    TYPICAL HYDROPNEUMATIC TANKWITH AIR COMPRESSOR

    Air Compressor

    Well Pump

    Pressure ReleaseWater Level Site Gage

    Check Valve

    Air ReliefMaster Meter

    HYDROPNEUMATIC TANK

    WellOutletInlet

  • Types of Hydropneumatic TanksFLOATING WAFER TYPE

    There is a floating wafer (usually constructed of a ridged material, flexible rubber, or plastic) that separates the air and water. This wafer, however, does not completely separate the air and water, and therefore some dissolving of air is expected. These tanks require occasional recharging with air

    wafer

  • Types of Hydropneumatic Tanks

    Tanks with Flexible Separator: These tanks provide a complete separation of the air and water. A separator is fastened around the inside of the tank (diaphragm type) or a bag is provided for containing the air (air bladder). These units may be charged with air at the factory, however most are fitted with an air valve (similar to a tire), which the operatorcan use to adjust the pressure inside the tank. Care must be taken when adding air to these tanks in order to avoid over-pressurization and a possible rupture of the separator. Manufacturers literature must be consulted before adding air to these tanks and the procedure should be performed only by qualified personnel

  • WATER

    AIR

    BLADDER TYPE

    WATER

    AIR

    DIAPHRAM TYPE

    Types of Hydropneumatic Tanks

    DIAPHRAMBLADDER

  • DESIGN CODE ASME SECTION VIII

  • CODE STAMPED VS. NON CODE STAMPED PRESSURE VESSELS

    XXAuthorized Inspection

    NOYESNOYES

    ASMENo Stamp

    CODE STAMPED

    XXWeld Map XXHeat No. Transfer

    XXReceiving ReportXXTraveler

    XXDrawings XXDesign

  • CODE STAMPED VS. NON CODE STAMPED PRESSURE VESSELS

    XXHydro Test

    NOYESNOYES

    ASMENo Stamp

    CODE STAMPED

    XXStamping XXData Report

    XXNDT XXWeld Visual Inspection XXWelder Qualifications XXWeld Procedures

  • CODE STAMPED VS. NON CODE STAMPED PRESSURE VESSELS

    XXP.O. Review by Q.C

    NOYESNOYES

    ASMENo Stamp

    CODE STAMPED

    XXOPTIONAL

    National Board Registration

    XXTraceability XXWeld Wire Certs XXMTR's XXFinal Inspection

  • HYDROPNEUMATIC TANKCONSTRUCTION

    WELDING

    JOINT EFFECIENCYTYPES OF JOINTS

  • BUTT WELDS

    TYPES OF WELD JOINTS

    LAP WELDS

    E = 100% IF FULL X-RAY

    E = 45% IF SINGLE LAP

    E = 85% IF SPOT X-RAYE = 70% IF NO X-RAY

    E = 55% IF DOUBLE LAP

  • Lap Welded Construction

    Lap Welds

  • HYDRO PNEUMATIC TANK CONSTRUCTION

    FOUNDATIONS

    Tank saddles

    Steel Concrete

    GROUND SUPPORT

    Water weighs 8.33 lbs/gallon a 30,000 gallon tank will weigh about 250,000 lbs or 125 Ton.

    Soil bearing must allow for this load.

  • HYDROPNEUMATIC TANK CONSTRUCTION

    HEAD TYPES

    HEMISPHERICALELLIPSOIDALTORISPHERICAL

  • Tank Diameter (D)

    ELLIPSOIDALr1 + R2 = K

    HEMISPHERICALR= 1/2D

    TORISPHERICAL

    R usually =D

    r r

    ACCEPTBLE TANK HEAD TYPES

  • FLAT HEAD

    DOME

    SHELL SHELL

    SHELL SHELL

    UNACCEPTABLE HEAD TYPES

  • PRESSURE VESSEL INSPECTION CODE:MAINTENANCE INSPECTION, RATING,

    REPAIR, AND ALTERATION

    API 510

  • NO SADDLE

  • Unsealed saddle

    Concrete pier

    Note saddle overhang

    SUPPORT PIER AND SADDLE

  • Improper head Radius

    Poor Weld

  • Code Stamp

    Sight Glass

    Factory Installed Pressure MW

    Air from Compressor

    All Butt WeldedJoints

  • This aftermarket 24 MH does not meet ASME Code and can be very dangerous

  • Severe dent may affect tank integrity

  • This tank blew its lid

  • Lap welded HeadNot welded