Ceramic Flat Plate Diffuser
Contents
The contents of this information leaflet must be read and fully
understood prior to using the product.
a. Application
The Dryden flat plate ceramic diffuser is a high performance
micro-bubble diffuser designed for use with the following gases
| Oxygen |
Ozone |
Carbon dioxide |
Nitrogen |
Air |
If other gases are to be used with the ceramic diffusers, please advise
Dryden Aqua for clearance. If the diffuser is to be used with air, the air supply must be
100% oil free and filtered down to 0.1 microns in order to remove any solids that may
block the diffuser internally.
Industrial sectors
Aquaculture the ceramic diffusers are designed for use in
aquaculture for both freshwater and marine systems. Typical applications for the diffuser
include the following aspects within the aquaculture industrial sector;
Oxygenation. of tanks, cages, ponds, fish transportation. The diffusers may also
be fitted inside header tanks or pipes supplying the water to the farm. If the diffusers
are fitted inside a pipe it is important that there is sufficient residence time in the
pipe to allow all of the oxygen to dissolve in the water, in order to avoid the potential
for air or oxygen locks in the pipework. If the diffuser is being used to diffuse oxygen
into pressurised vessels, the oxygen should be 100% pure. Any nitrogen or other gases
present in the gas stream will also dissolve into the water, which could lead to gas
bubble trauma in the fish or aquatic animals.
Ozonation. Diffusion of ozone into water using ozone produced
from air. If the diffuser is used with ozone produced from pure oxygen the warranty
conditions do not apply.
Anaethethetizing. Of fish in marine and freshwater systems using carbon dioxide. In
marine systems or hard water conditions, there may be excessive carbonate precipitation in
the ceramic plate air/water interface. In order to avoid back-pressure and possible
cracking of the diffuser it is important that the emery paper is used to thoroughly clean
the surface of the plate after use. This will prevent or reduce the accumulation of
carbonates.
Water Treatment the diffuser can be used in all water
applications where it is required to diffuse oxygen or the other specified gases into
water. If the diffusers are being used in a hard water environment there may be carbonate
precipitation, or heavy metal precipitation on the top surface of the diffuser. Under
these conditions it may be required to periodically remove the diffuser from the water and
clean using the emery paper to remove the surface precipitate.
In cases where the diffuser is being used in biologically active wastewater such as in
sludge plants, the diffuser may be prone to fouling from fats, lipids, organics, and
bacterial growth. Under these conditions to the diffuser should be remove at periodic
intervals and cleaned. Cleaning procedures will involve washing the diffuser in warm soapy
(mild detergent) water. Once the diffuser is clean and dry it should then be cleaned with
the emery paper.
Activated sludge tanks. The diffusers can be used in activated sludge plants, or
effluent treatment systems as a means of providing oxygen to aerobic bacteria.Discharge
channels. The diffuser can be used in the discharge channel from humus tanks or
discharge tanks as a means of increasing the dissolved oxygen content of the discharge
water. This process can be used as a means of complying with the discharge consent of the
facility.
b. Product Description
The Dryden Aqua diffusers is a high performance flat plate ceramic diffuser. The
diffuser frame is manufactured from cast aluminium and then enamelled in Dryden Aqua
green. The ceramic plate is secured in place using a high performance industrial epoxy.
Ceramic is a very strong material, however if mis-treated there is a risk that the plate
can crack. The design of the Dryden diffuser is such that the plate is fully supported
internally to improve the structural strength and impact resistance of the plate.The
key feature of the Dryden ceramic diffuser is the mist of fine bubbles produced from the
plate. When used according to the instructions, the plate will produce bubbles of a size
between 10 microns and 200 microns.
c. Installation & Operation
The diffuser when used in a tank should be located in the following position;
- The diffuser should be sitting horizontally to avoid bubble coalescence
- Install diffuser in the deepest point in the tank, this will give the longest residence
time of the bubble cloud in the water
- There should be no obstructions in the path of the bubble cloud; obstructions will cause
the bubbles to coalesce.
- A horizontal flow of water across the diffuser will improve performance
- Do not place two diffusers side by side
Any number of diffusers may be connected to the one oxygen or gas supply, the connection
onto the diffuser is by use of the tapered thread 1/4" hose tail. No PTFE or similar
type of tape sealant is to be used on the fittings.Four 6mm mounting holes are
provided on the diffuser. These mounts may be used to secure the diffuser to a specific
location. Do not over tighten these mounts, any distortion of the frame will cause stress
to the ceramic plate and may result in damage.
Gas feed pressure & flow
The maximum operating pressure of the diffuser is 45psi, the gas
lines supplying the diffuser must be fitted with pressure relief valves or automatic shut
down facilities that prevent any differential pressure in excess of 50psi. ( 350 kPa)
across the diffuser.
Typical operating pressures are between 20 and 35psi for the Dryden ceramic diffusers,
the table below gives the flowrates for oxygen that can be expected.
| Type |
Ceramic Plate area |
oxygen flow ( maximum) |
| DAD 3 |
300mm x 60mm |
3 litres per minute |
| DAD 6 |
400mm x 90mm |
6 litres per minute |
d. Health & SafetyOxygen
can be a very dangerous gas with a risk of fire or explosion. All health and safety issues
relating to the use of oxygen (and other gases) should strictly adhered to at all times.
Specific attention should be paid to insure that all fittings in contact with oxygen are
de-greased and are always free from oil, fats or other potentially combustible
hydrocarbons.
All fittings used with the Dryden ceramic diffusers should be compatible with the gas
employed.
In some cases not all of the oxygen will be dissolved into the water, under these
conditions there may be an increase in the oxygen levels on the surface of the water, in
the gas space above the tank, or in the room where the equipment is located. This point
should be noted and the appropriate health and safety features implemented appropriate to
the gas employed.
The maximum operating pressure of the diffuser is 45psi, the gas lines supplying the
diffuser must be fitted with pressure relief valves or automatic shut down facilities that
prevent any differential pressure in excess of 50psi. (350 kPa) across the diffuser.
Do not operate the diffuser, or pressurise the diffuser when out of water. The diffuser
must always be at least 500mm below the surface of the water when the gas is applied. Do
not touch or remove the diffuser when in use, do not put your had or any part of your body
closer than 500mm to the diffuser when in operation.
The use of the Dryden diffuser, and all aspects relating to health and safety are the
responsibility of the users. Dryden Aqua accepts no liability or consequential loss as a
result of the use of the diffuser.
e. Specification
| Parameter |
TYPE DAD3 |
TYPE DAD6 |
| Bubble size |
10 to 200 microns |
10 to 200 microns |
| Efficiency (depends strongly on conditions) |
approx. 40 to 80% |
approx. 40 to 80% |
| Connection |
1/4" BSP tapered thread, fitted with 1/4" hose
tail, 3/8" tail optional extra |
1/4" BSP tapered thread, fitted with 1/4" hose
tail, 3/8" tail optional extra |
| Materials of construction |
green enamelled cast aluminium ceramic porous plate
brass connections |
green enamelled cast aluminium ceramic porous plate
brass connections |
| Plate surface area |
300mm x 60mm |
400mm x 90mm |
| Overall dimensions |
346mm x 80mm x 26mm |
446mm x 107mm x 26mm |
| Plate weight |
1.5kg |
3.1kg |
| Maximum operating pressure |
45psi ( 300 kPa) |
45psi ( 300 kPa) |
| Setting for relief valve or shut down |
50 psi ( 345 kPa) |
50 psi ( 345 kPa) |
| Maximum gas flowrate |
3.0 l/min |
6.0 l/min |
| Recommend gas flowrate range |
0.5 to 2.0 l/min |
1.0 to 4.0 l/min |
f. MaintenanceThe Dryden Aqua
micro pore ceramic diffusers have been designed to give a long and trouble free life. When
the diffuser is used in water it will be prone to both chemical and biological fouling.
The diffuser should therefore be cleaned at periodic intervals.
If the diffuser appears to be fouled, or if the gas flowrate starts to fall off, then
it is and indication that cleaning may be required.
Cleaning procedure
1. Remove diffuser from water
2. Clean with a bristle brush to remove gross debris
3. Wash in clean fresh water, or water containing a mild detergent
4. Allow to dry
5. Run with emery paper
6. Rinse in fresh clean water
7. Dry diffuser and place in store, or place back into use
Disinfecting
The diffuser may be disinfected using a maximum of 50mg/l of hypochlorite solution.
Fill the diffuser with the hypochlorite solution and allow to sit submerged for 10
minutes. Remove the diffuser, drain out the hypochlorite solution and then wash in clean
freshwater to remove all traces of the disinfectant.
Storage
Storage temperatures should be between +5 degrees centigrade and 60 degrees
centigrade. Do not expose the diffusers to temperatures above 60 degrees centigrade.
g. Warranty & Conditions
Dryden Aqua provides a guarantee against any defect in the goods that is attributable to
the manufacture of the product for a period of one year from the date of purchase or 16
months from the date of manufacture, (which ever is the shorter time period). Defective
goods should be returned to Dryden Aqua suitably packaged for inspection. If it is
determined that the fault was due to defective parts or manufacture, the goods will be
repaired or replaced free of charge within the UK. For goods returned from out-with the UK
there will be a returned goods charge at cost price.Dryden Aqua guarantee is
conditional upon the following;
- The equipment must have been used and maintained according to Dryden Aqua instructions
- The guarantee will not cover any defects resulting from misuse of the product, neglect,
accidental damage, over pressurising or operation of the diffuser out-with the design
specifications
- Any attempt of the purchaser to repair the ceramic diffuser will render the guarantee
null and void
- Any defect should be reported within three days by fax or email to Dryden Aqua. The
goods should be returned to Dryden Aqua or an official representative of Dryden Aqua,
along with a written report on the circumstances leading up to the defect. Cost of
returning the goods to be born by the purchaser.
- The purchaser certifies acceptance of the guarantee as set out.
Limits of Liability Dryden Aqua obligations
specifically exclude any liability whatsoever for claims by the purchaser or user or any
other persons or parties;
In respect of merchantability, or fitness for a specific purpose. Or consequential
damages resulting from the use, or as a result of a malfunction of the equipment. For
personal injury or any medical or disability claims or for compensation arising therefrom.
The warranty and conditions, limitation and exclusions are accepted by the purchaser as
the only authorised and applicable warranty and that there are no other warranties or
conditions, oral or written, expressed or implied.
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