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Some heating devices for sea water aquaculture
Aquaculture, 4(1974)305-306 o Elsevier Scientific Publishing
Company,
Amsterdam
- Printed
in The Netherlands
Short Communications
SOME HEATING
GILBERT
DEVICES
FOR SEA WATER AQUACULTURE
BARNABB
Station de Biologie Marine et Lagunaire, She (France) (Received
May 8th, 1974; revised
September
20th,
1974)
ABSTR.$CT Barnabe, G., 1974. Some heating 305-306.
devices
for sea water aquaculture.
Aquaculture,
4:
The plroblem of heating large tanks of sea water is solved by the use of plastic sheated copper t-.ibe or newly developed electrical industrial material.
The .rearing of marine animals is now the main activity in many coastal laboratories. Experience and cultivation in practice require special material quite different from that of the laboratory, since some breeding and rearing problems can only be studied in large volume tanks (up to 1 m3). Maintenance of a suitable temperature is one of the most important factors in the study of requirements of marine fish. Convenient heating material is availa.ble for fresh water use, where fish culture is well established, and standard swimming pool or aquarium heating systems can also be used, although they are more expensive. The corrosive action of sea water on heat-exchanging surfaces makes the use of such apparatus very difficult, and indeed impossible; we therefore use the two following heating systems. (1) The use of plastic-sheathed
copper tubing
From the general central heating installation, every large volume tank (18-48 m3) possesses its own heating element regulated by a thermostatic tap. The heating element is a copper tube coil; before installation, the copper tube is covered with a sheath of reticulated polymers (P.V.C. or polyethylene) (Cie Franqaise des Isolants, Paris) of greater diameter. These polymers possess the property of shrinking when heated to lZO”C, and can be continuously used at high temperatures (SO-100°C). Different thicknesses of the sheath varying from 0.07 mm (P.V.C. sheath) to 1 mm (polyethylene sheath), are available. We use one sheath of polyethylene 0.7 mm thick and three sheaths of P.V.C. 0.07 mm thick. Because of the transparency of the plastic, one can easily check in each case whether the sheaths were waterproof. Coating can
306
easily be done with a small blow torch; material and labour are inexpensive. Shock resistance is excellent and the tank can be emptied with running hot water. Circulation of warm water in the coil is regulated by a thermostatic tap (Danfoss, Nanterre). The thermostat bulb lies inside a thin plastic cylinder filled with fresh water and is placedin the cultivation tank; in this way each tank can be regulated separately (from 0 to 30°C). With two coils of copper tube 20 mm in diameter, 10 m long, covered with a single polyethylene sheath (0.7 mm thick) we heat a 24-m3 exterior tank, in which the inlet water flow is 0.6 m3/h at S”C, water temperature in the tank 16°C and circulating hot water at 75°C. This system has been used without any trouble for 2 years. (2) The use of industrial electrical equipment Heating sea water electrically allows a precision better than 0.1% in temperature regulation. To avoid the danger of electrocution we use newly developed glass and plastic industrial material as follows. Shock-resistant glass heaters are available (power 1 000-3 000 W): the “Pyrex tube” is elastically suspended at the center of a perforated P.V.C. tube. For 1 000 W or less power, unbreakable plasticized heaters are also available. In each case the thermostatic bulb is also plasticized. (The perforated P.V.C. tube, plasticized heaters and thermostatic bulb were obtained from Chauffage Electrique Indust. Vulcain, Nogent sur Marne.) We have now been using such heaters successfully in a very humid atmosphere for 12 months.
Company,
Amsterdam
- Printed
in The Netherlands
Short Communications
SOME HEATING
GILBERT
DEVICES
FOR SEA WATER AQUACULTURE
BARNABB
Station de Biologie Marine et Lagunaire, She (France) (Received
May 8th, 1974; revised
September
20th,
1974)
ABSTR.$CT Barnabe, G., 1974. Some heating 305-306.
devices
for sea water aquaculture.
Aquaculture,
4:
The plroblem of heating large tanks of sea water is solved by the use of plastic sheated copper t-.ibe or newly developed electrical industrial material.
The .rearing of marine animals is now the main activity in many coastal laboratories. Experience and cultivation in practice require special material quite different from that of the laboratory, since some breeding and rearing problems can only be studied in large volume tanks (up to 1 m3). Maintenance of a suitable temperature is one of the most important factors in the study of requirements of marine fish. Convenient heating material is availa.ble for fresh water use, where fish culture is well established, and standard swimming pool or aquarium heating systems can also be used, although they are more expensive. The corrosive action of sea water on heat-exchanging surfaces makes the use of such apparatus very difficult, and indeed impossible; we therefore use the two following heating systems. (1) The use of plastic-sheathed
copper tubing
From the general central heating installation, every large volume tank (18-48 m3) possesses its own heating element regulated by a thermostatic tap. The heating element is a copper tube coil; before installation, the copper tube is covered with a sheath of reticulated polymers (P.V.C. or polyethylene) (Cie Franqaise des Isolants, Paris) of greater diameter. These polymers possess the property of shrinking when heated to lZO”C, and can be continuously used at high temperatures (SO-100°C). Different thicknesses of the sheath varying from 0.07 mm (P.V.C. sheath) to 1 mm (polyethylene sheath), are available. We use one sheath of polyethylene 0.7 mm thick and three sheaths of P.V.C. 0.07 mm thick. Because of the transparency of the plastic, one can easily check in each case whether the sheaths were waterproof. Coating can
306
easily be done with a small blow torch; material and labour are inexpensive. Shock resistance is excellent and the tank can be emptied with running hot water. Circulation of warm water in the coil is regulated by a thermostatic tap (Danfoss, Nanterre). The thermostat bulb lies inside a thin plastic cylinder filled with fresh water and is placedin the cultivation tank; in this way each tank can be regulated separately (from 0 to 30°C). With two coils of copper tube 20 mm in diameter, 10 m long, covered with a single polyethylene sheath (0.7 mm thick) we heat a 24-m3 exterior tank, in which the inlet water flow is 0.6 m3/h at S”C, water temperature in the tank 16°C and circulating hot water at 75°C. This system has been used without any trouble for 2 years. (2) The use of industrial electrical equipment Heating sea water electrically allows a precision better than 0.1% in temperature regulation. To avoid the danger of electrocution we use newly developed glass and plastic industrial material as follows. Shock-resistant glass heaters are available (power 1 000-3 000 W): the “Pyrex tube” is elastically suspended at the center of a perforated P.V.C. tube. For 1 000 W or less power, unbreakable plasticized heaters are also available. In each case the thermostatic bulb is also plasticized. (The perforated P.V.C. tube, plasticized heaters and thermostatic bulb were obtained from Chauffage Electrique Indust. Vulcain, Nogent sur Marne.) We have now been using such heaters successfully in a very humid atmosphere for 12 months.