Risorse professionali

De ce se utilizează cupru şi aliaje de cupru la fabricarea monedelor?

Din atichitate cuprul a fost folosit la fabricarea monedelor, romanii utilizau pe scară largă cuprul în acest domeniu. Motivele utilizării cuprului se datorează rezistenței excelente la coroziune, ușurinței de ștanțare, conductivităţii electrice bune (adecvat pentru automate), proprietăţii antimicrobiene şi uşurinţei de reciclare.

Gilt das Hartlötverbot auch für andere Anwendungsbereiche?

Nein! In Gasanlagen wird, wenn gelötet werden soll, das Hartlöten sogar zwingend gefordert. Ähnlich verhält es sich in Solaranlagen, bei denen eine besonders hohe thermische Belastung der Rohrverbindungen zu erwarten ist.
In Heizungsanlagen und anderen geschlossenen Systemen wie Solar- oder Kühlkreisläufen ist – im Gegensatz zu Trinkwasser-Installationen – durch das Hartlöten keine Korrosionsgefährdung zu erwarten, da der für Korrosionsvorgänge notwendige Sauerstoff in den Medien derartiger Anlagen nicht vorhanden ist. Hartlöten ist also auch hier möglich, wenngleich heute aufgrund ihrer einfachen Handhabung meist die Presstechnik angewendet wird.

Ho sentito che dall'anno prossimo il tubo di rame sarà vietato in Germania, o in Danimarca, non ricordo bene....

Non è vero. Queste sono voci false, che non hanno alcun fondamento. Il tubo di rame è il quello più usato, conosciuto ed apprezzato. Inoltre è quello più igienico per i suoi capacità di combatter la proliferazione dei batteri e per la sua salubrità.
Anzi, se ci segnalate chi mette in giro queste voci…

Do you need to feed solder into an integral solder ring fitting?

No, the integral solder ring fitting has the correct amount of solder to form a joint.

How can bronze works of art be protected from corrosion if they are situated outdoors?

Either by the use of lacquers, wax polishing, or both.

Doar cuprul pur are fect antimicrobian?

Nu, ci şi aliajele cuprului. Testele au fost efectuate pe cupru pur, alamă, bronz, cupru-nichel şi cupru-nichel-zinc (cele din urmă fiind denumite şi argint-nichel datorită culorii lucioase albe, chiar dacă nu conţin argint). Aliajele cu conţinut de cupru mai mare elimină mai repede microorganismele, dar ca o regulă generală, aliajele cu o concentraţie mai mare de 60% cupru au o eficacitate bună. Denumirea de „Cupru antimicrobian” este o denumire comună pentru aceste aliaje. La alegerea unui aliaj de cupru pentru un produs, este importantă echilibrarea diferitelor cerinţe, ca proprietăţile mecanice, procesul de fabricaţie şi culoarea. Aliajele cuprului oferă o paletă de culori atractive de la galben (alama) la maro închis(bronz).

Doar cuprul pur are fect antimicrobian? Sunt suprafeţele antimicrobiene de cupru învelite?

Nu, proprietatea antimicrobiană a cuprului este o proprietate intrinsecă a metalului. Pentru a menţine eficacitatea antimicrobiană uleiurile, ceara, materialele care dau luciu, vopselele sau alte materiale de învelire NU trebuie aplicate.

How can corrosion or staining of machined aluminium bronze components be avoided during shipping?

The key is to clean them thoroughly, remove water, protect them and keep them dry, so:

  1. After cleaning dry thoroughly using a dewatering fluid such as WD40.
  2. Remove displaced water with forced warm air.
  3. Coat with a protective coating such as benzotriazole inhibitor, or a block co-polymer.
  4. Pack into benzotriazole treated paper lined wooden boxes. Moisture absorbent granules may also be used to keep the air inside the boxes dry.

When unpacked, remove the coatings with a phosphoric-based solution and dry them thoroughly.

Does copper harden when stored for long periods of time?

Copper will not harden during storage; it does not have a shelf life.

How is Bordeaux mixture prepared?

Bordeaux mixture is prepared in various strengths from copper sulphate, hydrated lime (calcium hydroxide) and water. The conventional method of describing its composition is to give the weight of copper sulphate, the weight of hydrated lime and the volume of water in that order.

The percentage of copper sulphate weight to the weight of water employed determines the concentration of the Bordeaux mixture. A 1% Bordeaux mixture, which is the norm, would have the formula 1 :1:100, the first 1 representing 1 kg copper sulphate, the second representing 1 kg hydrated lime, and the 100 representing 100 litres (100 kg) water.

As copper sulphate contains 25% copper metal, the copper content of a 1% Bordeaux mixture would be 0-25% copper. The quantity of lime used can be reduced considerably. 1 kg copper sulphate requires only 0.225 kg of chemically pure hydrated lime to precipitate all the copper. Good proprietary brands of hydrated lime are now freely available but, as even these deteriorate on storage, it is safest not to exceed a ratio of 2:1, i.e. a 1:0.5:100 mixture.

In preparing Bordeaux mixture, the copper sulphate is dissolved in half the required amount of water in a wooden or plastic vessel. The hydrated lime is mixed with the balance of the water in another vessel. The two ‘solutions’ are then poured together through a strainer into a third vessel or spray tank.

How is copper used on a farm?

Copper sulphate, because of its fungicidal and bactericidal properties, has been employed as a disinfectant on farms against storage rots and for the control and prevention of certain animal diseases, such as foot rot of sheep and cattle.

Does a sprinkler head use more or less water than a fire brigade hose in controlling a house fire?

Much less water.