Resource Library

What advantages do copper alloy cages offer?

Copper alloy mesh cages resist predator attack, prevent fish escapes, offer good corrosion resistance and a low susceptibility to marine organism attachment. They provide improved water flow and circulation, and help maintain higher oxygen levels which gives a healthier environment for the fish. This results in higher yields and lower maintenance, and the copper alloy is infinitely recyclable at the end of its life.

What kind of cleaning do copper alloy cages require?

On average, copper alloy cages must be cleaned approximately once or twice a year, which is significantly fewer than traditional cages, over a service life.

What makes a sprinkler head activate?

When the sprinkler head reaches a certain temperature it will activate.

What manufacturing methods would be suitable for lock parts made in high tensile brass?

Either extrusion, if the shape is regular, or hot stamping for more complicated shapes.

My datacentre has a UPS. Is that enough protection?

How important is it that your data integrity is maintained and that your users have instant access to it?

A (static) UPS has a finite energy store so that, in the event of a supply failure it will provide power for a short time. This available time can be used in several ways depending on the needs of the organisation.

It can be used (and most frequently is used) to perform an orderly shut down of the network and servers. This protects transactions and ensures integrity of the data. However, once triggered, the process allows no new access to data – i.e., your users have no service. Service is only restored after the power supply has been re-established and the servers and network devices re-booted. If the operation is losing money by the minute, this is unlikely to be acceptable!

Another approach is to use the limited time available to start up an auxiliary generator to take over the supply from the UPS. This allows the operation to continue as if nothing had happened – assuming of course that the generator and fuel supply are properly maintained and work as expected.

Alternatively the time can be used to transfer transactions to another site, either an active peer site or a passive standby site. Again, as far as users are concerned, nothing has changed.

Whatever approach is taken it is most important that the standby power available is used carefully. Only essential equipment should be connected to the UPS system – servers, communications, network devices, essential PCs – no coffee machines, laser printers, etc.!

A specification describes a brass as CDA 360. What is this?

This is an old CDA Inc (USA) spec—it is now UNS C36000. The UK equivalent is CW603N (CZ124) and is a free machining brass.

My process control system is not reliable and I suspect a voltage dip problem. Where do I start?

The steps in identifying the problem are:

Monitor at the supply to one or more of the affected devices. One problem is that the monitor threshold settings need to be set carefully so that all interesting events are captured, but the smaller, uninteresting events are not. This can take some trial and error to get right, but it improves the quality of data that you collect and is worthwhile. Alternatively, choose a tool that applies the thresholds retrospectively – these capture all the data, but let you choose what you view. Often, the simple transient capture functions found on hand-held power analysers are useful in the early stages – they are simple to use, the results are easy to interpret and they are easily moved around the installation.

Assuming that the first stage identifies that you do indeed have a voltage dip problem, you now have to find the source.

Move the analyser back to the origin of the supply, i.e. the point of common coupling (PCC) and monitor there. Monitor the current in each phase as well to check for increased current correlating to voltage dips (although it may be difficult to identify them at this measurement position). If the voltage dips are less frequent and have a higher retained voltage, and if there are identifiable correlated current increases, then the dips are caused by equipment in your own installation. Move forward, monitoring the voltage dips at each distribution point together with the current on each sub-circuit, and the source of the problem should be revealed. You can also take a more pragmatic approach and test circuits feeding heavy or cyclic loads first – suspect photocopiers and laser printers, lifts and hoists, heating and ventilating equipment, presses, arc furnaces…

Once you have found the problem, the solution is simple. The disturbing load must be wired directly to the PCC – lowest impedance point in the system – so that it has the least effect on voltage.

If the voltage dip performance at the PCC is similar to that at the load, then it is more likely that the source of the dips is outside your installation. Now you have the evidence to talk to your Distribution Network Operator.

What method of protection may be used for the transport/shipping of brass finished products?

It is common to use a tarnish inhibitor prior to transporting brass components. These are based on benzotriazole. One such product is Armagard produced by a UK company, Armack Chemicals. Hot water is added to the Armagard and the component is dipped into the solution, then flash dried. Components are then wrapped in acid free paper. No standards relate to this process.

Are weld repairs permissible on Class 1 and Class 2 nickel aluminium bronze forgings produced to Def Stan 02-833?

No, the rectification of defects by welding is not permitted on Class 1 and Class 2 (high integrity) forgings.

A 3% leaded brass tube, used to make an electrical fitting, cracked on crimping. Why?

Lead reduces the ductility of brass so use a tube with 1% lead.

A brass water fitting in dezincification resistant brass has been brazed. Should it be re-heat treated?

Yes, heat to 500 to 525oC, hold for two hours and slow cool, to ensure an all alpha structure.

A drawing refers to a material as B16. What is this?

B16 is an ASTM specification for free cutting brass rod and bar.