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Front view of SCAM / SWT2 treatment systemRear view of SCAM / SWT2 treatment systemSCAM / SA sulfuric acid dosing systemSWT2 functioning simplified system

SCAM/SWT2 - SCAM/SWT2-PLUS - SCAM/SA WATER TREATMENT SYSTEM

Sometimes the water consumption into an operating cooling tower has a significant impact and it is determined by: evaporated water, dragged water (through the drift eliminators, but normally lower than 0.002% of the circulating tower water) and purge water (based on the concentration cycles). The consumed water is periodically re-integrated. The water level in the collecting basin is controlled by an automatic make-up floating valve (SCAM/VL), which can be supplied upon request. As explained water evaporation increases water salinity. This entails the opening of a purge valve at regular intervals to restore the correct salts concentration of the solution. At the same time, the following measures are carried out:  

  • - an anti-scaling product (paragraph 3.2) in proportion to the volume of re-integrated water in the circuit in order to prevent the precipitation of dissolved salts;
  • - a biocide product (paragraph 3.3) through a timed method in proportion to the volume of water in the circuit by regular shocks dosages to prevent the proliferation of micro-organisms within the system.

Remote and/or local control water treatment system SCAM/SWT2 consists of a device that measures conductibility (SCAM/WCNT2) with an automatic purge control, of a pH measurement system and of chemical products dosing with redundancy of the  pumps. The system has the following components:

  • - No. 1 HDPE support skid to be placed on the ground, complete with No. 2 PVC transparent coverage and protection panels wherein are placed the pumps, the products storage tanks, the instrumentation, valves & fittings and plastic tubes. The components are installed on both sides of the skid to optimize spaces;
  • - No. 1 product dosage control system for each pair of pumps through Flow-control device and  predisposition for the sensor measuring corrosion on copper and zinc (materials that usually characterize pipelines of tower circuit and of heat exchanger combined with tower users);
  • No. 1 measuring system SCAM AEGIS (SCAM/EGS) having a pH and conductivity analysis sensor to control an automatic purge motorized valve in relation to the tower water conductivity. AEGIS system has the predisposition to provide the corrosiveness measurement on specific metals and RedOX reactions (optional);
  • - No. 1 hydraulic set (PVC piping, manual interception valves, Y filter, sample taking point, manometer, no-return valve) and connections for analysis sensors;
  • - No. 1 power supply panel endowed with thermo magnetic protection;
  • - No. 1 spherical 2-way electrical valve (purge);
  • - No. 1 anti-scaling dosage system with two electromagnetic pumps (one on stand-by) complete with a tank aspiration set and water meter (to be installed on the tower water make-up) and minimum level switch to block the pumps in absence of chemical product (low level). A local mechanical switch is installed to select the operating pump and the stand-by one for the dosage of the specific chemical product;
  • - No. 1 biocide dosage system with two electromagnetic pumps (one on stand-by) complete with a tank aspiration set and a minimum level switch to block the pumps in absence of chemical product (low level). A local mechanical switch is installed to select the operating pump and the stand-by one for the dosage of the specific chemical product;
  • - No. 2 storage tanks (biocide and anti-scaling) made of HDPE having a volume capacity of 140 lt each, housed in support skid and with predisposition for products inlet;

In the supply purpose are included the storage tanks of biocide and anti-scaling, excluding the same products.  The water treatment system is controlled onsite; but it can be managed remotely through a SCADA software,  purposely studied in order to create graphic telecontrol functions of AEGIS device.

Should it be necessary to control the pH of the water in the system, by monitoring the water corrosive action in the tower circuit, SCAM T.P.E. S.r.l. offers the possibility to implement some additional devices on the above water treatment system that becomes SCAM/SWT2-PLUS. SCAM/SWT2 system already includes wells for housing additional and the control device of the reading signals AEGIS. In particular, SCAM/SWT2-PLUS system can also include, upon request:

  • - No. 1 measuring sensor for RedOX reactions;
  • - No. 2 corrosion sensors for Copper and Zinc;
  • - No. 1 “stand-alone” SCAM/SA hanging unit equipped with a transparent door with two parallel dosing pumps  to be installed on the wall for the dosage of sulfuric acid with a 98% p/p concentration controlled by the reading of PH of tower water solution.

The additional skid SCAM/SA in HDPE includes dosage and interception lines in PVDF for the air/water purification, spherical sectioning valves inlet and outlet to  the electromagnetic dosage pumps. The feeding pumps contain counter pressure security valves together with an overflow sensor to be connected to the SCAM/AEGIS device. The electrical wiring on the SCAM/SA skid is available, with predisposition for external connections.

 

SYSTEM FUNCTIONALITY

As shown in the figure, in the SWT2 system water coming from tower circuit spillage (pos. 1) flows through a manual interception valve. It immediately reaches a Y-filter that stops any possible impurities and then enters the hydraulic section where various detection sensors of SWT2 system are installed, such as the conductivity meter, the pH probe and optionally the RedOX and corrosion sensors. (pos. 2).

The conductivity sensor, including a compensation temperature sensor, measures the conductivity value of the circulating water and matches it with the set value determined by the user (set-point). If the measurement overcomes the set-point, the panel controls the solenoid opening in order to drain the saturated water (pos. 3). Optionally, the readings of the values coming from pH, corrosion and RedOX sensors can be visualized on SCAM/AEGIS device on the SCAM/SWT2 skid. The pH measure signal can be elaborated by SCAM/AEGIS device that transmits an input to SCAM/SA skid (if included), this one doses the required quantity of acid to correct tower water pH in accordance to the set-point determined by the user.

In SCAM/SWT2 system, water coming from “measuring sensors” section flows through a sample taking zone and a no-return valve before meeting the chemical products injection section (pos. 4), and then introduced once again in the recirculation circuit of the evaporating tower (pos. 5). The two dosing pumps (one of which is redundant on stand-by in order to avoid dosage interruption in case the other pump doesn’t work) are positioned on the system support panel to carry out:

  • - the anti-scaling dosage (inhibitor);
  • - the biocide dosage;

The membrane electromagnetic SCAM/PVT200-B pump, injects the biocide (pos. 6) periodically, and can be programmed through its own internal timer to enable the product to flow into the circuit in accordance to the desired quantities.

The membrane electromagnetic SCAM/PVT200-I pump injects (pos. 4) the anti-scaling / corrosion inhibiting product proportionally to the replenished water volume in accordance to the impulses received from the water meter (pos. 6) to be installed on the tower water replenishing line. 

Dosing  pumps are programmable onsite, but on request there is the possibility to control them remotely  through a 4-20 mA signal. The pumps are built in plastic material, suitable for contact with the chemical products to be injected  in the tower water circuit. 

At the end of each pump is placed a flow control device, which  checks the single pump strokes according to the principle of the body in suspension.  This safety device can be set through an adjustment screw in order to send a warning signal when the dosed flow is approximately 20% lower than the  set-point.

The optional SCAM/SA skid for the sulfuric acid dosage is positioned on an independent panel and it can be supplied electrically, connected for the pH signal reception  and mechanically installed by the client.

Are not included neither the storage tank nor the chemical product for SCAM/SA skid, but the connections for the product suction are pre-installed.

The monoblock SCAM/SWT2 skid is in fiberglass and has approx. size of 1000 x 1200 x 2000h mm with an indicative weight of 280 kg. It does not need to be anchored on wall, but it can be positioned on the ground by the client.  For the correct functioning of the plant are provided the make-up flow meter and the purge solenoid that have to be hydraulically mounted on the installation and electrically wired (there is a predisposition) to SCAM/SWT2 switchboard by the client. 

The monoblock SCAM/SWT2 skid is in fiberglass and has approx. size of 1000 x 700 x 1500h mm. This skid has to be anchored on wall and supplied and electrically connected by the client. 

Suggested chemical products for dosage into water tower circuit are respectively: a biocide and an anti-scaling, and eventually acid for the pH correction, whose dosages depend on the water quality (chemical and biological characteristics) and on specific process parameters. In the case of pH correction, the use of concentrated sulfuric acid (98% in weight) is recommended. In order to ensure the best performance of the cooling tower in accordance to the specific operational conditions of the system, it is necessary to refer to the company providing the chemical products who remains entirely responsible for the treatment program.

 

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For a specific quote, please contact SCAM T.P.E. S.r.l. Commercial Department.