Unit 12 Processes and operations
12.1 How does it work?
12.1 C
Questioner: So how does a photocopier work?
Explainer: Well, basically they work on the principle of electrical charges.
Modern photocopiers make use of static electricity - no ink is involved, as it used to be.
Questioner: Well, how do the marks get onto the paper?
Explainer: Well, if you open up the inside of the photocopier underneath
where you lay the sheet of paper you want copying,
you'll see...ooh, you'll see a lot of things going on.
Questioner: Well, what actually happens when you press the start button?
Explainer: Well, there's a drum, which is specially coated with a material
which conducts electricity when light shines on it.
This drum turns around.
First it's given a negative static electric charge.
That's very important.
Questioner: What does the light do?
Explainer: Well, you see, at the same time as the drum is being charged,
your original which you've laid face down over the glass top is exposed
a little at a time to a light which moves over the document.
This image is projected onto the drum as it revolves and the electrostatic charge destroys the light.
Questioner: Right. But...um you said that the image, or printed magerial,
that it no longer comes from ink,
as it used to, so how do the marks get onto the paper?
Explainer: Mhm. Yeah, well before that can happen toner powder
which is negatively charged is dusted or brushed onto the drum.
And it is attracted to the charged parts on the drum.
That is the toner sticks to those parts.
And those are the marks on the document,
that is, the parts that have kept their el...their static electric charge.
Questioner: Right. Yup.
Explainer: And w...after that ocmes the transfer stage.
The sheet of copy paper is positively charged.
And in this way it attracts the toner.
Questioner: And is that when it actually comes out of the photocopier?
Explainer: That's right.
Questioner: But why's the paper hot when it comes out of the machine?
Explainer: Ah, well,...
And that is the end 12.1 C
12.2 What do I have to do?
12.2 A
Woman: OK, Bob. So first of all, you make sure that there's paper.
Woman: Yes, fine...there. And then you put the document down. Face down.
Woman: And then you indicate in the digital display here how many copies you want.
Woman: So that's...er...what? Two. We want two.
Woman: And then you press the button.
Man: Easy as that?
Second conversation
Man: OK, so you've got your document. OK. Two pages. So, the first page, OK, you turn face up.
Man: And you feed it into the slot here, and it takes it in automatically.
WOman: Oh, right.
Man: Yeah? And then you dial the number that you want.
Woman: What here?
Man: Just there, yeah. And you...you press the green button.
Man: OK. And it dials the number automatically.
Man: And it connects with the fax at the other end.
And...um...and then it automatically sends the first page.
It just feeds through. Oh, right, yes.
Man: And then when the first page is finished,
there's a 'beep'...and...er...and it's simple,
you just feed in the second page.
that's right. That's right.
Man: Yeah. And then at the end there's another beep,
which you ignore and wait for the...just wait for the line to disconnect
and then you see the display there says: FAXDONE. And that's it.
Woman: Oh, right. Oh, I think I can manage that.
Third conversation
Woman: OK, so you want me to set the alarm for tomorrow morning?
Man: Show me how to do it, yeah.
Woman: OK, I'll show you. First of all, you press MODE.
Woman: That's what it's set at now, 6.07.
Man: No, no, no.
Woman: Too early?
Woman: Right. I press this button. Now, 7.07?
Man: No. 7...7.30.
Woman: 7.30. OK. So I press the other button. 8,9,10...
Man: It's a bit like the video.
You just have to keep on pressing that button, until we get to 28,29,30. OK?
Now press MODE again. But the numbers are still flashing. So...
Woman: Press MODE again.
Woman: That's 2.19 now. And then I press that and the alarm is set to come on.
Man: All right.
Woman: Tomorrow morning at 7.30.
Man: Excellent.
Woman: A pleasure.
Man: Thanks.
And that is the end 12.2 A.
12.3 A production process
12.3 B
Speaker: In the case of all Cadbury's chocolate products the basic ingredients ,
are of course, cocoa beans.
We buy our cocoa beans from Ghana and some from Malaysia.
50,000 tonnes of cocoa beans are processed each year at the factory
but that's before the actual chocolate-making process can be started.
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in revolving drums at a temperature of about 135 degrees.
The actual time for roasting depends on whether the use at the end is for cocoa or chocolate.
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Well first, in the kibbling stage the beans are broken down into small pieces.
And at the same time the shells are blown away by air currents.
The technical term for that process is 'winnowing'.
And so, then you've got the broken pieces of cocoa beans.
And those are known as 'nibs'. OK?
in mills
until the friction and the heat of milling reduces them to a thick chocolate coloured liquid.
The result of the grinding stage is known as 'mass'.
Now, this contains 55 to 58% cocoa butter
and,of course, that solidifies as it cools.
And it's the basis of all chocolate and cocoa products.
in heavy presses.
And that cocoa butter is late added back in the chocolate-making process.
Right then, now after the mass has been produced,
we come to the actual chocolate-making process itself.
I'm going to tell you about the production of milk chocolate.
Well, at the milk factory the mass, the cocoa mass,
to a very thick liquid.
The resulting chocolatey creamy liquid is then dried.
At that stage it's called 'chocolate crumb'.
Then that's taken to or factories at Bournville and Somerdale in Bristol.
There, the 'crumb' is mixed with the additional cocoa butter and special chocolate flavourings.
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again and pulverized further.
The chocolate, which has had sugar and cocoa butter added to the mass before grinding and pulverizing,
now undergoes the final special produciton stages.
Now, the most important component of chocolate as far as the texture is concerned,
is the addition of fats.
are essential in the process:
they control the texture and viscosity of the chocolate before it can be used in the manufacturing process.
Are you with me so far? Good!
Now 'conching' involves mixing and beating the semiliquid mixture to develop flavour
and reduce the viscosity and the size of the particles.
Well basically, what this means is that it stops it becoming too sticky and enables it to be manipulated.
And then comes the tempering.
This is the last stage and it's crucial:
what it mean is mixing and cooling the liquid chocolate under very carefully controlled
conditions to produce chocolate in which the fat has set in its most stable crystalline form.
It is the tempering of the chocolate that gives it the famous Cadbury smoothness,
and gloss and the snap.
Without this last process the chocolate would be very soft and gritty,
and there'd be large crystals inside it and it would have a very dull grey appearance.
Well then, there we are, that's how milk chocolate is made...
And that is the end 12.3 B.