Rink

Brine Control To fully understand the use of brine, we should know something about its chemical behavior. Pure water freezes at 32°F (0°C). As soluble salt is dissolved in the water, its freezing temperature is lowered. The greater the amount of salt dissolved, the lower the freezing temperature, until a point is reached where adding salt does not lower the freezing temperature. Any salt added beyond this point just settles at the bottom of the pipes or container and will eventually block off the pipes, thus causing a breakdown in the system. This lowest possible freezing point is called the eutectic point and varies with the different salts. The common brines used in various refrigeration systems are sodium chloride (NaC1), and calcium chloride (CaC12). The eutectic point of sodium chloride is -6°F (-21.1°C) and of calcium chloride is -59°F (-50°C). ccalcium chloride brine is universally used in artificial ice plants because of it has a low eutectic point and is reasonably cheap. The actual choice of proper brine concentration involves several factors. If insurance against freezing were the only requirement, the brine could be kept as strong as possible, up to the eutectic point. However, the stronger the brine the heavier it becomes, therefore, more pumping power must be used to circulate it. Also the stronger brine makes the specific heat less, therefore, more brine must be circulated to do a given refrigeration job. For the above reasons, the brine should only be kept strong enough so it will not freeze when against the refrigerated surfaces in the brine chiller, usually the coldest part of the system. Recommended minimum strength is 1.2 specific gravity with a freezing point of -10°F to -15°F (-23.3° to -26.1°C). When mixing brine, the mix is approximately 35 imperial gallons (132.48 liters) of water to a 100 pound (45.4 kg) bag of calcium chloride, or a proportion of these amounts. The brine must be thoroughly mixed before it enters the system and can be pumped into the low pressure side of the system using a small utility pump. Fresh brine is in an alkaline condition when it enters the system, and care must be taken that it remains alkaline. The strength of acids and alkalis is measured by a scale calibrated from 1 to 14, called pH scale. A pH of 1 is the strongest acid; a pH of 14 is the strongest alkali and a pH of 7 is neutral. Brine are normally slightly alkaline, and their recommended pH depends upon the inhibitor used within the brine. A pH of between 8.5 and 9.5 is typical. Brine should be analyzed every year by a specialized lab that can accurately ascertain and measure the inhibitor used. ★ Source: Refrigeration Manual: Ice Rink Applications. © 2007 Ontario Recreation Facilitiies Association, Inc. (www.orfa.com). Reprinted by permission from Facility Forum magazine, January 2007, Vol.15: Iss. 4. 34 R INK MAGAZ INE MAy/June 2007 To add new brine, the tank should be filled with fresh water and flaked calcium chloride added. B R I N E M A I N T E N A N C E B R I N E M A I N T E N A N C E

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