A single-source system provides benefits and prevents issues associated with multi-supplier setups.
Considering the climate of today's municipal pumping system market, engineers seem to be turning toward prefabricated pumping systems with integrated chemical treatment equipment. Because of insurance regulations, if there are problems with a system during startup, major component manufacturers' representatives are only allowed to comment on their equipment and its functionality. This condition has generated a need for manufacturers to provide single point responsibility. Demand also seems to be increasing for speedy completion of many projects, perhaps required by the need to conserve capital caused by the current economy.
Benefits of a Single Source
Single-source responsibility for the entire system—pumps, motors, valves, piping, controls, instrumentation and chemical treatment equipment—eliminates the possibility of "finger pointing" that has been associated with different suppliers combining their products into a site-built system. Each of us has likely experienced the frustration created by each supplier taking responsibility only for the equipment they provided and not its interaction with other components and with the distribution system. Statements such as the ones below are commonplace:
- "The controls are working properly. The problem must be with the pumps."
- "The pumps are performing to curve. The problem must be with the valves."
- "There is no problem with the valves. It seems to be that the controls are not set right."
And so it goes with no one seeming to understand the overall function of the whole system. Single-source responsibility means that one entity, the pumping system manufacturer, takes responsibility for the system and all its components, as a whole, providing the pumping system manufacturer's warranty that supersedes individual component warranties. In addition, the pumping system manufacturer provides personnel to troubleshoot any potential system problems at no charge during the warranty period. The manufacturer most likely has a network of qualified technicians throughout the country for service after the warranty period. These qualified technicians can be employees of the manufacturer, representatives of the manufacturer or third party service organizations that have been determined by the manufacturer to be competent to service the equipment supplied.
Until recently, a number of pumping system suppliers could provide integrated pumping systems, but either could not or would not provide the treatment equipment required for treating the pumped water. The increased requirement for pumping and chemical treatment integration has narrowed the integrated pumping and treatment system field significantly to only a few companies that are competent in that integration area.
An Integrated System—a Case Study
One such integrated system is currently in service today. The pumping and treatment system described in this section was released for production on August 21, 2009, and the system was shipped February 2, 2010, a time span of 165 calendar days, or 107 working days. This time span included:
- Acquisition of equipment
- Fabrication
- Fusion bonded epoxy coating of the piping
- Assembly
- Painting of the system
- Fully functional flow testing of the system
- Electrical calibration and testing of the system
- Final assembly, including the installation of the pumping system enclosure
NEC and OSHA clearance requirements were maintained, and the system and its controls were each UL listed as an assembly.
The Enclosure
The system enclosure (building) was manufactured to the requirements of the state to which it was destined and carried that state's required label. This enclosure was mounted on the pumping and treatment skid, and the entire product was delivered to the site as a single unit.
This enclosure is a self-framing metal building with a standing seam metal gable roof. The exterior façade is Fullerton Finish Systems WalStone siding. Three doors are supplied, one double door for the chemical room, one double door for the pump room and one roll up door for pump room service.
The interior finish is white pebble textured fiberglass reinforced plastic (FRP) over plywood, which covered R-21 insulation. A sealed internal partition separates the pump room from the chemical room. Floor drains are provided in each room, as well as ground fault interrupting receptacles, fluorescent lighting, emergency lights, smoke alarms and door switches for intruder alarms. There is an HVAC unit in the pump room and a heater and ventilation in the chemical room.
Piping
Water inlet piping rises through the floor in the chemical room, passes through the partition into the pump room, where it encounters a gate valve, strainer and flowmeter before it becomes the suction manifold for the pumps. In this case, the engineer required the chemical treatment to be injected into the piping prior to the water being passed through the pumps. The manufacturer reviewed the type of chemicals to be used and the chemical resistance of the devices and materials wetted by the treated water. After finding that all the materials and equipment were compatible with the chemicals to be used, the manufacturer raised no objection to the chemicals being introduced prior to the pumps.
If the chemicals could have had detrimental affects to the wetted equipment and materials, the manufacturer would have contacted the engineer to explain the potential adverse affects and would have requested that the chemicals be injected after the water had passed through the pumps and valves.
Treatment System
Two chemical feed systems were installed which used dosing pumps, pH sensors and analog signal from the flow meter to provide accurate dosing based on flow rate. The chemicals injected were aluminum sulfate from one dosing system and potassium permanganate from the other. Chemical equipment for each type of chemical included a 200-gallon storage tank with through wall filling port, through skid overflow port, spill containment pallet and elevated tank stand, and two Stenner peristaltic metering pumps with PVC valves, injection lances and connection tubing.
Pumps, Valves and Connections
Lug pattern butterfly valves having aluminum bronze discs, EPDM liners and hand wheel operators were provided as the isolation valves for the pumps and the pressure relief valve. Single-sphere flexible connectors made from EPDM rubber were provided on the suction side of the pumps to facilitate service of the pumps and motors. Each pump was a Peerless close-coupled, end-suction pump with mechanical seal, cast iron casing and bronze impeller.
Each pump had a Cla-Val 40A-01ABD flow control valve with orifice plate whose orifice was sized for the flow and pressures required of this system. These valves were required to assure a constant flow rate into the elevated storage tank that this system filled. The setting of these valves was calibrated to the flowmeter of the system to assure an accurate setting of the valves' pilots.
A pressure relief valve was supplied to prevent excessive pressure being applied to the discharge pipeline in the event that someone closed the fill valve to the elevated storage tank without turning the pumps off first. It also provided some degree of protection to the pumping system components in the event of water hammer generated by the loss of power while a pump was running.
Electrical and Control System
Electrical controls included an automatic transfer switch (provided on site by others), main disconnect breaker, control panel with breakers and starters for the pumps and alarms, telemetry interface panel, and RTU (provided on site by others). An enclosure power supply was provided by SyncroFlo, which included a primary breaker, step down transformer, and load center with breakers for power distribution to building equipment, such as HVAC, lights and receptacles.
Shipment and Delivery
For shipment, the loose items were protected and then strapped down to prevent damage to themselves or other equipment within the chemical room. Once the equipment arrived on site, the contractor off loaded the equipment, set it in place, connected the inlet and outlet piping, installed the automatic transfer switch and RTU, connected power and called the manufacturer for a start-up technician to start the system and place it in operation. Chemicals for use in the chemical room were supplied on site by others.
As a result, the engineer and customer received a fully functional pumping and treatment system integrated into a single package, needing only piping, power, RTU connections and the addition of chemical to the storage tanks.
Pumps & Systems, June 2011