INSTALLATION INSTRUCTIONS FOR Airflex™ WIDEBAND DIFFUSER
Comment Sheet :
1. Installation, Operation and Maintenance Manual contains detailed information on the SSI Airflex™ Wideband Diffuser unit. This manual covers start-up, operation and maintenance procedures.
2. SSI Airflex™ Wideband diffuser unit has an operating headloss
of approximately 10-25 inches of water when operated in normal airflow ranges
(0 to 45 scfm normal). Confirmation of blower pressure requirements provided
by others.
General
The Airflex™ wideband diffuser units are furnished completely factory assembled. The only work required by the Contractor is the installation and placement of the diffuser units on the laterals piping.
SSI recommends care in handling and storage to prevent damaging, puncturing or banding of the diffuser frame. If units are to be stored before installation, SSI recommends utilizing the original unopened shipping cartons. Store in a clean location that avoids potential mechanical damage.
Air distribution through the Airflex™ diffuser is a function of the individual diffuser elevation. For proper system operation, SSI recommends a leveling tolerance of ± 1/2" for the diffuser unit. If the diffusers are mounted with excessive elevation tolerances, the airflow distribution in the system will be adversely impacted.
Shipment/Storage of Equipment
1. Upon delivery, check equipment for structural damage during shipment. Damages must be reported to SSI within 10 days of delivery.
2. Store Airflex™ units in a location that prevents exposure to excessive heat, oils or aromatic hydrocarbons.
Installation of Airflex™ Wideband Diffuser Assembly
1. SSI designed the Airflex™ Wideband diffuser for field installation on tapped lateral piping or tee. The lateral piping must have a 3/4" NPT tapped outlet placed horizontally in the lateral piping.
2. It may also be installed in female threaded sockets welded & stainless pipe, or to 90 ° SS elbows welded and the bottom center line of gusseted SS headers.
3. Place the threaded end of the diffuser into the threaded outlet hole.
Tighten the diffuser unit by rotating clockwise. DO NOT OVER TIGHTEN. Over
tightening the unit will cause failure to lateral piping, diffuser unit
or both. Detail drawing of the Airflex™ Wideband diffuser unit may
be found in Section 2.
When blower assemblies, header piping, air laterals, and all units are properly
installed, system is ready for start-up. Refer to Airflex™ Start-up
Instructions for details.
AIRFLEX™ START-UP INSTRUCTIONS
General
These instructions cover the general start-up requirements for the Airflex™ diffuser system. Special start-up requirements outlined in the Engineer's specifications, contract documents, or instructions offered by SSI shall be supplementary to or take precedent over these general instructions.
An overview of Start-up procedures is related below:
1. Confirm that piping and diffusers are level by filling the basin with water. Adjust supports for diffusers as required.
2. Continue filling the basin with water until the diffusers are 1" to 2" under water. In the event of air leaks, the diffusers are accessible.
3. Activate the blower and introduce air to the Airflex™ system. Check piping and diffusers for leaks, and repair if required.
4. While maintaining air to the system, continue filling the basin until the design depth is reached.
A. Blower Components
Refer to the blower installation and start-up to ensure that all blower components are mounted properly and ready for operation.
B. General Air Piping
Contractor is to confirm the cleanliness of the air piping. If existing header piping is used, the air purge or water flush cleaning procedure is recommended prior to installation of Airflex™ units to remove any internal debris that may have accumulated in the header piping. Inspect air piping and diffuser connections for loose fittings or damaged pipe. Damaged piping sections and connections should be repaired prior to commencing system operations. Refer to cleaning procedures in this Section.
SSI Airflex™ Aeration/Mixing System
(Optional) Water Flush of Piping
General: These instructions cover the general procedure which may be utilized to clean the piping in diffuser system. Special pipe cleaning requirements outlined in the Engineer's specifications, contract documents, or instructions offered by SSI shall be supplementary to or take precedent over the general instructions outlined below. Note: Diffuser should not be installed during cleaning procedure. Debris may dislodge and plug units.
A. Water Flush Cleaning
1. Water flush cleaning is the recommended method to clean assembled piping systems where pipe segments are too long for manual cleaning. This procedure can be used in conjunction with air purge cleaning and is recommended when fine debris is not removed prior to assembly of piping. When both water flush and air purge is used, the water flush procedure should be implemented first.
2. To water flush the system, connect a water supply to the air header or make individual connections to each lateral. If flush water is piped to the header, it is imperative that the header be valved or stubbed such that water does not flood the blowers.
3. Clean water must be employed. It is not necessary to use potable water but the hush water must be free of silt or debris.
4. Flush header assembly prior to water flushing the laterals. Header, fill it with water and open the end lateral to create a in the header of at least two feet per second (if possible).
5. The laterals are to be individually flushed next. A flush velocity of five to six feet per second is recommended for lateral cleaning.
OPERATION INSTRUCTIONS FOR AERATED BASINS
The Airflex™ aeration-mixing system employs individual diffuser assemblies
attached directly to the lateral piping. SSI normally designs the aeration
piping system to provide uniform distribution of air without requiring adjustment
of the isolation/throttling valves on the laterals with the exception in
situations where water level variation exists. However, these valves are
typically provided for direct control of airflow distribution on large aeration
systems or for process control.
Normal Operation of the Aeration System
The following procedures should be followed on a regular basis to assure consistent and satisfactory performance of the Airflex™ aeration-mixing system.
The air rate to the system may be adjusted to maintain the desired dissolved oxygen levels in the basin. When adjusting the air flowrate, the diffusers should be operated within the normal operating range of the diffuser. Excessive air flowrates will result in higher pressure drops across the diffuser. Low air flowrates may result in incomplete utilization of the diffuser media and reduced air distribution.
The Airflex™ aeration-mixing system is designed to provide uniform aeration. Positive dissolved oxygen concentrations should be present throughout the entire system during normal operation. A dissolved oxygen profile analysis may be used to confirm the performance of the aeration system. Typically, the dissolved oxygen levels are measured at the inlet, the outlet, and the midpoint locations of each basin to determine the aeration system performance. In regulating the system airflow to control dissolved oxygen levels, the diffuser units should be operated within their minimum and maximum airflow limits.
Varying Water Level Operations
In applications where water level variations may exist between aeration basins supplied by a single blower, the isolation valves may need to be adjusted to maintain adequate airflow distribution. This normally requires valving back the air to the basin with the reduced water level. NOTE: It is important to confirm
the operating airflow range of the diffuser units before valving back any isolation valve. Damage could result to the aeration diffuser if airflow is above the recommendations enclosed herein. Please consult SSI Engineering Department to confirm operating procedure before adjusting any aeration isolation/throttling valve.
Trouble Shooting
The Airflex™ aeration system requires very little maintenance for long term operation. Periodic visual inspection of the system should allow the Operator to determine if the system is performing at optimum levels. For example, diffuser unit elevation variations greater than the design tolerance, typically ± 1/2" will reduce the uniformity of air distribution in the system. In addition, operating airflows below the design condition will also reduce the uniformity of air distribution. If operating conditions warrant air flow rates below the design condition, contact SSI for additional operational guidelines.
Below are symptoms and procedures to follow if inspection of the aeration system reveals abnormal operating characteristics.
1. Large volume of air in localized area
Possible Cause: a. Air leak in aeration piping.
b. Diffuser damaged or missing.
Procedure: a. Drain basin to access area in question.
Maintain airflow to units. Inspect joints for
evidence of breakage.
b. Inspect diffuser units for missing orifice.
Replace orifice as required.
2. Decreased diffuser activity and increased backpressure noted at blower.
Possible Cause: a. Reduced blower air volume.
b. Restriction in air header.
Procedure: a. Access diffusers and inspect for external fouling in orifice.
b. Confirm blower operating point and rpm reading.
c. Confirm isolation valve position on header and drops.
3. Dissolved oxygen profile not satisfactory throughout basin.
Possible Cause: a. Increased loading to system.
b. Reduced blower air volume.
c. Improper distribution of air in system.
d. Air leak in system.
Procedure: a. Confirm loading to system.
b. Confirm blower operations.
c. Reference items 1 and 2 above.
Normal Operation of the Blower System
The Airflex™ Aeration-Mixing System normally utilizes a centrifugal or positive disp1acement (PD) blower system consisting of one or more blower units for normal operation plus one on-line spare unit. All blower units including the spare unit must be operated on a regular basis to maintain their proper working condition. SSI recommends that blower units be operated sequentially with idle blower units brought on-line weekly. SSI does not recommend the simultaneous operation of on-line and spare blowers for an extended period. This operating condition may deliver airflows exceeding the air capacity of the diffuser units.
All blower components should be serviced on a regular basis. For additional information concerning proper blower operation, service requirements or service intervals, reference the Blower Operation and Maintenance manual.
Shutdown Conditions
If an interruption in air service is experienced at any time, restoration
of air service should be instituted as soon as possible. When restarting
positive displacement blower units, follow blower suppliers recommended
procedures. Operate water purge devices if provided. If the PRV releases
air for an extended period of time, the relief setting should be checked.
If the basin is to be idle for a prolonged time period, the basin should
be drained and cleaned. Note, maintain the minimum airflow to the system
during the drain down procedure. For maximum protection of an aeration system
with plastic components (pipe, diffusers), refill the basin with clean water
to completely submerge the aeration system. This provides thermal protection
in the event of severe cold or hot weather conditions. Do not allow this
water to freeze so it is advisable to keep the blowers running. For maximum
protection of an aeration system made entirely of stainless steel, for long
term storage we recommend draining the basin.
Contact SSI for additional operation and maintenance information if it is necessary to decrease the system airflow during cold weather.
Operation of the Airflex™ Diffuser
The Airflex™ unit has no moving parts and requires very little maintenance for long-term operation. SSI recommends that the air supply to the diffusers be maintained at all times for optimum performance. The airflow to the AirflexÔ units must be kept within the ranges summarized in Table 1 to maintain the structural and operating characteristics of the diffuser media. Continuous application of high airflows, greater than denoted for normal operation may result in physical damage to the diffuser media. Under no circumstances should the airflows indicated as maximum be exceeded. Note: Use caution when adjusting several lateral throttling valves in the same piping system. This procedure can result in elevated airflows in sections of the basin, exceeding the maximum allowable airflow to each AirflexÔ unit.
MAINTENANCE INSTRUCTIONS FOR AERATED BASINS
The SSI Airflex™ unit is a coarse bubble aeration device that offers maximum benefits for mixing. Proper operation and maintenance of the Airflex™ diffuser can provide years of long term performance with minimum energy cost and minimum maintenance cost.
Proper maintenance procedures will also minimize the frequency of system interruptions. The following guidelines should be referenced in maintaining the Airflex™ diffuser system.
1.The diffuser Wideband should be protected from high PH products,
2. Some evidence of increased headloss through the diffuser unit may be experienced over a long period of operation. This pressure build-up is often the result of biological and/or inorganic materials building up inside of diffuser. The propensity for this condition is job specific and is a function of the type of waste, and the specific operating characteristics of the system. To restore performance and decrease the operating headloss, refer to the following sections.
Accessing the Airflex™ Diffuser Assembly
SSI recommends that the Airflex™ units be accessed on a regular basis (annually) to visually inspect the units. The AirflexÔ aeration system is designed to allow the diffuser units to be accessed by dropping the water level in the basin being serviced. The air to the basin being serviced should be turned off to prevent the possibility of excessive airflows to the units or damage to the blower unit.
The following items may be helpful in servicing the Airflex™ diffuser assemblies during periodic inspections or maintenance procedures:
1. Ladder to access the de-watered basin
2. Protective gloves and clothing
3. Long-handled bristle brush for cleaning assembly for observation
Replacing Airflex™ Diffuser Assembly
If it becomes necessary to remove an entire Airflex™ assembly, the general procedures outlined below should be followed.
1. Shut off air supplies to unit.
2. Unthread unit from lateral piping.
3. Reinstall the diffuser unit following installation details in Section 3.
Properly operated and maintained, the Airflex™ aeration and mixing
system will provide years of high efficiency treatment with minimum operator
attention. Questions regarding Airflex™ system operation, maintenance,
etc. should be forwarded to the Engineering Department.
Stamford Scientific International Incorporated,
4 Tucker Dr, Poughkeepsie, N.Y. 12603 U.S.A.
Tel: (845) 454-8171 Fax: (845) 454-8094
Email: info@stamfordscientific.com
