Laundry engineering
Basic laundry designing parameters
1. Laundry building
• 1.1. Surface - 0,8 - 1,2 m2 / kg/h capacity
(for production hall only)
• 1.2. Height – 3,5 m /minimum/
or – otherwise – accordingly to
technological requirements
• 1.3. Ventilation of the production hall
• To remove excess of heat from the machines acc to the
national standards
• Average 6 – 8 air exchanges per hour
2. Laundry installations
2.1. Water for technology
•
•
•
•
•
Hardness above 1,45 mval/dm3 (some hard water
can be needed as well)
Fe content – less than 0,1 mg/dm3
Mn content – less than 0,05 mg/dm3
pressure /inlet to the machines/ 0,3 – 0,6 MPa
consumption
A) washer –extractors
20 – 25 dm3/kg of linen
B) tunnel batch washers 6 – 10 dm3/kg of linen
Basic system on the following slide
Laundry. Water preparation
T ~ 10oC;
pmin=0,3 MPa
pmax=0,6 MPa
10oC;
fresh water
T~
pmin=0,3 MPa
pmax=0,6 MPa
hard cold water
p=0,3 - 0,6 MPa
hardness> 1,43 mval/l
Softening station
T ~ 10oC;
pmin=0,3 MPa
pmax=0,6 MPa
pmin = 0,2 – 0,5 MPa
T ~ 10oC
hardness< 1,43 mval/l
soft cold water
Retention
tank
Pressure station
pmin = 0,2 – 0,5 MPa
T ~ 10oC
hardness< 1,43 mval/l
If Fe content > 0,1 mg/dm3;
Mn content > 0,05 mg/dm3
extra purification is needed
T ~ 55oC;
pmin=0,3 MPa
pmax=0,6 MPa
pmin = 0,2 MPa
T ~ 55oC
Water heater
Retention
tank
soft warm water
Pressure station
2. Laundry installations
2.2. Steam for technology
• source - municipal, boiler or steam
generator
• pressure at the outlet (of the boiler) p=16 bar
• working pressure p = 13 / 8 / 5 bar
• consumption : ca 2,5 – 3,5 kg/kg linen
• return of condensate : ca 65 % of total steam
consumption
Basic system on the following slide
Laundry. Steam distribution
p=13 bar
13 Æ 8 bar
8 Æ 5 bar
p= 5 bar
p= 8 bar
Steam
generator
Presses
Tunnelwasher
1,0 kg/kg l
Ironers
0,9 - 1,1
kg/kg l
0,45 kg/kg l
Dryers
1,3 kg/kg l
(0,9 kg/kg l
with
recircul.)
pump
Washerextractors
Waterheater
0,8 kg/kg l
1,0 - 1,5
kg/kg l
Condensate collector
Condensate
Tank
Condensate lines
Fresh soft water
2. Laundry installations
2.3. Waste water
•
•
- amount
- quality :
•
•
•
•
•
•
Æ
pH
Temp.
Detergents
BOD 5
COD
is the consequence of the consumption
– 8 – 12
- 30 – 90 oC
- 20 – 50 mg/dm3
- 50 – 600 mg O2/dm3
- 500 – 5000 mg O2/dm3
– treatment - in two ways
• Drain to municipal sewers
• Reuse (even partly) as feeding water for washers
2. Laundry installations
2.3. Waste water
• regeneration of the waste water
• System 1 - chemical regeneration
• System 2 – bio-chemical regeneration
• Other
The following slides will present the examples of the complex
methods
2.3 Waste water regeneration
system no. 1
waste water from the laundry
FM
mechanical filtration
d<0,3mm
solid parts
d > 0,3mm
N
neutralization
HCL acid addition
UF
ultra filtration
d=0,01-0,2 µm
UO
UF concentrate
Dissolved substances - salts
reversed osmosis
d=0,001-0,01 µm
nano filtration
Heavy and/or colour metals
UO concentrate
- organic salts
Selective ionic
exchange
Fe, Pb, Mn, Cu, Ni ions
Regenerated water for re-use
2.3 Waste water regeneration
system no. 2
waste water
Waste water temperature
and quality unifying
Buffer tank
Retention tank
24 h process
t < 40 oC
Bio-reaction tank
flocculation
aggregating of the
contamination particles
UV disinfection
residue
Chemical disinfection
Re-use water
sedimentation
2. Laundry installation
• 2.4. Compressed air
• pressure
• consumption
- p = 8 – 10 bar
- 0,3 – 0,5 Nm3/kg linen
• 2.5. Electricity (for technology)
• total power installed
0,20 – 0,60 kW per 1kg linen/h
• energy consumption
0,15 – 0,30 kWh / kg linen