All language subtitles for S14E09 - Headphones; Diving Regulators; Reflector Light Bulbs (1080p AMZN WEB-DL x265 Garshasp)_track3_[eng]

Narrator: in the early part
Of the 20th century,

Headphones were used mainly

By telephone operators
And radio technicians.

But in the 1930s,

They were redesigned
And marketed to the public,

So music lovers everywhere
Plugged in

And turned on to the concept.

Everyone is a music critic,

But headphones allow people
To crank up the volume

Without negative feedback
From neighbors.

To make high-end headphones,

An injection-molding machine
First makes plastic back covers.

The mesh area will allow
Sound waves to pass through

Instead of reflecting back
Into the headphone.

Down the line,

Equipment stamps trademark
And other information

Onto two more
Casing components --

A decorative metal disk,
And a plastic housing.

The next machine
Winds copper wire

That's as thin as human hair

Around a cylinder
Hundreds of times.

The winding
Is computer controlled

To produce
A critical component --

The headphone's voice coil.

When magnetized
By an incoming signal,

The voice coil
Vibrates a diaphragm,

Causing it to emit sound.

That diaphragm now takes shape

As a press applies heat and
Pressure to a plastic membrane.

These tools mold the plastic
To the desired shape.

The press molds the plastic
Thicker in the center

And thinner
Around the outer zone

For a wide and flat
Audio-frequency range.

A technician punches out
The molded shape.

She applies a bead of glue
To the diaphragm,

Then positions the copper voice
Coil in an assembly device.

She aligns the glued section
Of the diaphragm with the coil.

Ultraviolet light
Activates the glue

To seal the coil
To the diaphragm.

The plastic housings
Each contain a magnet.

The next technician
Installs the diaphragm

And voice-coil assembly
On that housing.

This takes skill

Because the coil must be
Positioned precisely

For the best sound quality.

And this headphone speaker
Is now ready for an audio check.

A technician tests
The audio-frequency range,

Distortion, and other factors.

Here, a technician joins
The ends of curved wires

In a plastic clip.

These wires
Serve a dual function.

They hold the headphones
Snugly over the ears

And deliver audio signals

From the left side
Of the headphones the right.

The next technician
Installs a connector

For the headphone's audio cable
And a plastic strain relief.

An adjustable band
Will allow the headphones

To fit on heads
Of all shapes and sizes.

The operator presses the parts
Together with a hydraulic tool.

Moving down the line,

A technician now joins the two
Halves of the speaker housing.

She forces
The two parts together

With a pneumatic tool...

And finishes it off
With a decorative metal ring.

She inserts
The speaker mechanism

In the center of the housing,

Then places plastic brackets
Over it for protection.

She then secures the entire
Assembly to the housing.

Next, she solders two wires
To each headphone speaker.

A plastic ring and cover
Protect it

While still allowing the wires
To protrude.

She attaches the end of
The headband to the speakers...

...Then solders the wires
From the speaker

To those protruding
From the headband.

She presses a plastic grille
Into place

Over each speaker
Very carefully,

To prevent scratching.

The headphones are now wired
And ready for audio.

And whether it's rock
Or classical,

The choice of music
Will be silent

To all but one individual.

Narrator:
The diving regulator is a
Lifeline when you're underwater.

Invented in 1937,

This device converts
Compressed air from diving tanks

Into a breathable form

And delivers it to the diver
Via a mouthpiece.

And that means,
Once you've taken the plunge,

You can breathe easy.

The two main parts of a diving
Regulator are called stages.

Computerized tools
Transform a piece of brass

Into the first-stage housing.

They carve a cavity and holes

For attaching hoses
And other components.

A blade cuts the part to size.

Then, a drill creates a space

For the
Pressure-reduction valve.

This end also gets holes
For more attachments.

Another tool sculpts the side to
Reduce the weight of the part.

Sliced in two,

This is how the first-stage
Housing looks inside.

After it's been chrome-plated,

They insert plugs for the holes
That will later be used

For attaching gauges, hoses,
And other parts.

The fitting that connects
The regulator to the scuba tank

Goes into a holding device,

While the technician
Assembles a special valve

For keeping salt water out.

He fits a piston
Onto the end of a spring,

And then slips the assembly
Through a hole

To confirm it's the right size.

He installs a filter
On the other end of the spring.

Now he inserts the valve
In the fitting.

He secures it
With this rubber ring,

Pressing it into a groove
In the fitting.

The valve appears
To be firmly entrenched.

He presses it to confirm
It operates correctly.

And he pumps water
Into a bunch of these fittings

To confirm the valves inside
Are, indeed, watertight.

He attaches a rubber cover
And a chrome-plated yoke

To the fitting,

Then installs this assembly
In the housing,

Using a long-handled socket
Wrench to get the right torque.

This yoke swivels to give
The diver some flexibility

In attaching it
To the diving tank.

He now assembles
A crucial component --

The high-pressure
Reduction valve.

Installed inside
The first-stage housing,

It converts high pressure
To medium pressure.

He caps the yoke with a knob,

Then inserts
A pressure-sensing mechanism

At one end
Of the first-stage housing.

He covers it
With a rubber membrane.

As the diver inhales,

This membrane will trigger
The valve to release more air.

The diving regulator's
First stage is now complete.

He just needs to calibrate the
Pressure-reduction valve inside.

He hooks it up to compressed air
And adjusts the valve

So it reduces air pressure
To a precise level.

He immerses it in water
To test for air leaks.

There are a few bubbles
From plunging it underwater,

But nothing that would indicate
A problem.

They now move on to the diving
Regulator's second stage,

Which will convert
The medium-pressure air

From the first stage
To a breathable level.

The diver's breathing
Will trigger this diaphragm

To open the air valve.

He attached a protective cover,

And he's ready to install
The second-stage valve.

After he inserts it
In the second-stage housing,

The technician makes
An initial adjustment.

Then, using a special tool, he
Precisely calibrates the valve.

He removed the diaphragm for the
Last steps, so he reinstalls it.

Then, it's over to a guy
With an ear for the job.

As air is pumped into
The second stage,

He listens for hisses
That would indicate a leak.

Satisfied there are none,

He hooks the regulator
Up to a device

That simulates breathing

And measures the effort
Required to inhale.

If it checks out, they link
The two stages with a hose,

And this diving regulator is now
Equipped to handle the pressure.

Narrator: good lighting is often
A matter of reflection,

And that's why, early on,

Lamps often came
With reflectors.

But, in 1935, a company figured
Out how to make light bulbs

With built-in reflectors.

Sealing the reflectors
Inside the bulb

Kept them clean
And maintenance-free.

As track lights
Or in recessed fixtures,

Reflector bulbs can light up
A room at the flick of a switch.

The creation of these bulbs
Begins with the bulb shell,

Known as the glass envelope.

It's comprised of numerous raw
Ingredients and recycled glass.

Production is almost
Entirely automated.

An operator activates equipment
That weighs the ingredients

And releases them
Into a huge hopper,

Where they're mixed thoroughly.

This concoction
Then flows into a furnace

Heated to 2,700 degrees
Fahrenheit.

It takes up to 24 hours

For the mix to melt
Into a taffylike glass.

It flows between rollers
That shape it into a ribbon.

One roller has little pockets
On the surface,

Which form the ribbon
Into segments.

These devices,
Called blow heads,

Inflate the glass segments

Through holes
In the conveyor chain.

This stretches the glass into
Oblong bubbles called blanks.

Iron molds encase the warm
And pliable glass blanks.

The molds spin as the glass
Hardens into the desired shape.

The glass blanks now look like
Upside-down martini glasses.

This is the reflector bulb's
Glass envelope.

It takes just seconds for
A glass blank to be transformed

Inside one of these molds.

The envelopes are still linked
By a ribbon of glass at the top,

So an automated hammer
Now gently knocks them free.

The glass envelopes
Cool down slowly.

This stage, called annealing,

Toughens the glass
To reduce brittleness.

They measure the thickness
And diameter

Of one of the envelopes.

If it's not up to standards,

The entire production run
Will be crushed,

And the glass recycled
Into new ones.

But the envelope is good,
And so, production continues.

They lower the envelopes
Over nozzles

That inject hydrofluoric acid.

It coats the inner surface of
The glass with a frosty finish

That will smooth the light
Emitted by the bulb

And widen the beam.

The envelopes
Now head down a chute,

Into a padded channel
That cushions their fall.

Guides gently position them.

Then, other devices
Thrust them into holders

Which move them down the line.

Next, a robot inserts
Aluminum wire in a heating coil

And places a protective
Metal dome over top.

Suction cups
Pick up the glass envelopes

And slide them onto
The wire-and-dome assemblies.

A pump pulls air out of the bulb

As an electrical current
Energizes the heating coil

To melt the aluminum wire.

The aluminum adheres to the
Walls of the light bulb's shell,

Giving it a reflective finish.

The glass envelopes then move on

To be stamped with the company
Trademark and other information.

Meanwhile,
On another production line,

They're preparing
The glass mounts

For the filament
And wire contacts.

A cutting wheel
Slices them to size.

The tubes then travel past
A flame,

Which melts the ends just a bit
To make the edges smooth.

Once they've cooled,

Grippers deliver the tubes
To a more intense flame,

Which flares them at one end.

Coming up next, we'll show you
The inner workings

Of the reflector light bulb.

Narrator: a reflector light bulb
Can cast one's surroundings

In a whole new light --

One that's more intense
And focused.

The source of this light is
An electrified filament of wire.

And assembling that filament in
The bulb is a very delicate task

That's performed
Entirely by machines.

Production now focuses
On the glass tube

That will serve as the mount
For the filament

And its electrical contacts.

Machinery inserts
Two copper wires into each tube.

These are the lead wires

That will eventually connect the
Base of the bulb to the filament

And deliver
The electric current.

These long glass tubes
Will be used

To suck air
Out of the light bulb,

Preventing oxygen from reaching
The filament and destroying it.

They protrude
From the glass mount,

But that's just temporary.

They will later be cut shorter.

Torches now melt
The glass mount,

Lead wires,
And exhaust tube together.

Mechanized fingers then pinch
The layers together,

And the wires
Are now encased in glass

But protrude
From the glass base.

Grippers transfer
The closed mounts to a carousel.

It revolves to allow the mounts
To receive a coil

Made of tungsten metal.

This coil is the filament
Of the reflector light bulb.

Mechanized fingers
Attach the small coil

To hooks on the two lead wires.

The coiled filament is wobbly,

So next it gets some support.

First, machinery bends
The lead wires

To move them and the filament
Out of the way.

Then, a robot presses the tip
Of the glass exhaust tube

Onto a burner.

The tip melts,

Allowing a metal support wire
To be embedded into it.

Another robot
Bends the lead wires

To position the filament
Adjacent to the support wire.

The next station loops the wire
Around the filament.

This gives the filament
The necessary support,

And it stops wobbling.

This 2-pronged device then
Straightens out the lead wires.

The mount is now upright
And riding another carousel.

Flippers set it straight
So a metal disk can be installed

On the pinched section
Of the mount.

This disk is reflective.

It will bounce light downward

To the shiny coating
Inside the light bulb,

To create just the right effect.

With the disk wrapped around it,

The assembly is now positioned
On the next turntable.

Suction cups deposit the glass
Envelope on the assembly,

To encase the filament
And reflective disk inside.

The holder twirls the bulb as it
Travels past a row of torches.

The flames melt the neck
Of the glass envelope,

And it closes
Around the glass mount.

This secures the filament,
Contacts, and reflective disk

Inside the bulb.

Another set of torches, heated
To a much higher temperature,

Trims the base of the bulb.

Molding devices now move in
To shape the bottom of the bulb

So a metal base
Can be fitted to it.

A gripper then puts
That metal base on a track

To meet up with
The reflector light bulb.

By now, the bulb
Has been flushed of oxygen

And filled with argon gas
So it will last longer.

The metal base finishes it off

And will allow the bulb to
Be screwed into a light fixture.

Another flame
Heats the metal base

To cure adhesive
That was preapplied

For a strong bond to the bulb.

Then, robots cut off
Protruding wire

And form a contact on the base.

It has taken just 12 minutes

To assemble
This reflector light bulb,

But it will provide
About 2,000 hours of light.

--captions by vitac--
Www.Vitac.Com

Captions paid for by
Discovery communications

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