Jonshon Screen

8/13/2019 Jonshon Screen

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Intake Screens


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Johnson Screens Design


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3Johnson Screens Design

State of the Art Fabrication

All welded cylindrical construction

by specially built rotating screenmachines

ISO 9002 Shop ASME & AWS Certified

welders


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4Johnson Passive Intakes

Drum screens are formally known asSingle Screens.

They are designated by the letter S (forsingle) in their model numbers.

The number also indicates the diametermeasured in inches (example: S-24).


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5Johnson Passive Intakes

Tee screens get their name from their shape.

Tee screens are identified by the letter T in

their model number (example: T-48).The number designation is the diameter of thecylinder measured in inches.


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6Passive Intake Advantages

Complies with Screening Regulations

EPA & NMFS Guidelines

Proven Design

Highly efficient with low flow velocities

Self Cleaning

Air Back Wash (ABW) System

No Power Requirements

No moving parts

Low Maintenance Requirements

No parts to replace or maintain

Low Environmental Impact

Debris or aquatic life will not be held against the screen

surface


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7Patented High Flow Design

New Design:

DUAL Open Pipe Flow Modifier

Old Design:

Single Flow Modifier

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2


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8Velocity Curve Graphic

M a x V e lo c i ty.5 f ps

N e w d e s ig n v e lo c itya v e ra g e = .4 5 fp s

O ld d e s ig n v e lo c i tya v e ra g e = .3 5 f p s

V el o c i t y P r o f i leC u r v e s


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CFD Velocity Analysis

Screen Surface

Secondary Flow ModifierInitial Flow Modifier


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10Open Pipe Flow Modifier

Dual Flow Modifier

Allows Same FlowCapacity with 20-30%

Smaller IntakeAllows Intake Extension

Lower Pressure Drop

Non-Plugging Design

Smaller ABW


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11Hydroburst Systems

Removes debris with a sudden blast of air stored in areceiver tank at the surface.

Air volume is usually 3 times the volume of the intake.

Air is released all at once, not a continuous flow.Manifold within intake bottom distributes the air andcreates a scouring action as the air rises and expands.


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12Hydroburst Components

1. Compressor

2. Receiver Tank

3. Control Valves4. Control Panel

5. Airburst


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13Hydroburst Components


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14Hydroburst Function

(Intake End Views)

1 Second4-5 Seconds2-3 Seconds

Indicates Air Flow Pattern


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15Hydroburst Operation


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16Hydroburst Sizing Factors

Distance to intake screen

Diameter of screen

Effective displacement volume

Size of air backwash lineDepth of screen

Size of air tank

Required time to rechargeSophistication of controls


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Pressure Drop vs. Blockage

Percent Blocked

PressureDrop

Delta-Tracker


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18Z-Alloy Material

Proprietary copper/nickelalloy that effectively resists

Zebra mussel and algaeattachment

NOT A COATING!

Does not adversely effectenvironment by leaching

Is a passive deterrent

No effective operating costs

Does not lose effectivenessover time


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19Z-Alloy Test Screen

J.H. Campbell Power Plant Lake Michigan

Z-Alloy Side

of Flange

Stainless Steel

Side of Flange

Z-Alloy

Screen isbolted to 304

sections.

Z All T t S


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20Z-Alloy Test Screen

J.H. Campbell Power Plant After 6 Years!

M th d f I t ll ti


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21Methods of Installation

M th d f I t ll ti


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Thank You! Questions?

Documents

Jonshon Screen