nash gravity filter agenda

Report
NASH PULP & PAPER DIVISION
NASH GRAVITY FILTER
Introduction and Application
NASH GRAVITY FILTER
AGENDA  How it works
 How it fits into our current product mix
 Advantages/Customer Benefits
 Sizing & Selection
 Pricing & Delivery
 Accessories
NASH GRAVITY FILTER
• 316 SS construction
• One moving part
• Innovative “Bottom-Up”
cleaning technology
• Integral gear motor with
no seals or bearings in
contact with process water
• Variable speed drive
unit for improved cleaning
• Two piece screen for easy
maintenance & inspection
NASH GRAVITY FILTER
HOW IT WORKS -
10-12 RPM
5 RPM possible w/low
fiber concentration
NASH GRAVITY FILTER
BOTTOM -UP CLEANING METHOD -
• 50-60% of Spray Water passes to “rejects” discharge
• Spray nozzles overlap each other by 30%
NASH GRAVITY FILTER
BOTTOM -UP vs. TOP -DOWN CLEANING -
• Lifts fibers/debris off of screen
• Minimizes potential for clogging
• Allows a larger mesh than equivalent
“top-down” filter
• Sweeps debris/fibers across screen to
a central collection point
• Forces debris/fibers into and through the
screen - Increases potential for clogging
• Requires small mesh screen to prevent
pass through of fibers
NASH GRAVITY FILTER
EXAMPLE OF TOP-DOWN METHOD -
NASH GRAVITY FILTER
HOW IT FITS INTO OUR PRODUCT MIX • Used to filter incoming water stream to cooling
tower
• Used as a prefilter for shower water
NASH GRAVITY FILTER
FEATURES & CUSTOMER BENEFITS  Superior “bottom-up” cleaning technology
prevents screen clogging
 Variable speed drive motor for optimum
cleaning performance
 One moving part with no bearings or seals
exposed to process water
 All stainless steel construction
 Two piece removable screen for easy
inspection and maintenance of internals
NASH GRAVITY FILTER
SIZING & SELECTION The minimum information required to size a
gravity strainer is,
•
•
•
•
Flow rate
Fiber loading (PPM, and fiber length)
Application
Screen mesh size
NASH GRAVITY FILTER
SIZES & FLOW RATES Model No.
Flow Rate (GPM)
BSW -10
70 - 350
BSW - 14
150 - 650
BSW - 17
260 - 1050
BSW - 22
400 - 1850
BSW - 25
660 - 2650
BSW - 30
925 - 3600
NASH GRAVITY FILTER
Flow
(Liters/min.)
Fiber Loading - Mg/liter (PPM)
NASH GRAVITY FILTER
FLOW FACTORS Multiply the following factors by the flow rate when
using the screen sizes listed below,
Screen Mesh
Size
Flow
Factor
140 micron (100 mesh)
1.15
100 micron (150 mesh)
1.25
80 micron (200 mesh)
1.40
Reminder : Mesh size = No. of screen threads/mm
Micron size = Size opening between threads
NASH GRAVITY FILTER
FLOW FACTORS -

When using 100 mesh screen with water based on
waste paper, refiner ground wood newsprint, and
ground wood, use a flow factor of 1.70
NASH GRAVITY FILTER
SIZING EXAMPLES Size a gravity strainer for the following conditions,
1. 4000 LPM, 300 PPM - 100 mesh screen
2. 4000 LPM, 300 PPM - 150 mesh screen
3. 3000 LPM, 150 PPM (waste paper) - 150 mesh screen
NASH GRAVITY FILTER
ANSWERS 1. 4000 LPM x 1.15 = 4600 LPM
4600 LPM @ 300 PPM ---> BSW-25
2. 4000 LPM x 1.25 = 5000 LPM
5000 LPM @ 300 PPM ---> BSW-25
3. 3000 LPM x 1.70 = 5100 LPM
5100 LPM @ 150 PPM ---> BSW-22
NASH GRAVITY FILTER
SPRAY WATER FLOWS & PRESSURES Model No.
No. of
No. of
Spray Pipes Nozzles*
Spray Water Flow** (LPM)
2 bar
3 bar
4 bar
5 bar
BSW -10
2
10
50
65
75
85
BSW - 14
2
14
75
90
105
115
BSW - 17
2
20
105
130
150
170
BSW - 22
2
26
135
165
195
215
BSW - 25
2
32
165
200
235
265
BSW - 30
2
38
200
240
280
315
* - Spray Nozzles : 2.7 mm orifice, 60 degree fan
** - Spray Water flows contain 10% safety factor
NASH GRAVITY FILTER
SPRAY WATER FLOWS & PRESSURES Recommended Spray Water Pressure • 2-3 bar (30-45 psig) on BSW-10 thru BSW-17
• 3-4 bar (45-60 psig) on BSW-22 thru BSW-30
General Rule of Thumb The smaller the mesh, the higher the pressure
required for cleaning
NASH GRAVITY FILTER
ACCESSORIES STANDARD  316 Stainless Steel
Screen
 316 Stainless Steel
Tub Material
 Galvanized Backing
Flanges w/316 SS
Angle Ring
 110V Panel Input
Power
OPTIONAL  Police Filter for Spray
Water Flow
 Polyester Screen
 304 Stainless Steel
Screen
 316 SS Backing
Flanges w/316 SS
Angle Ring
 230V/380V/415V
Panel Input Power

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