At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door & latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

See pics here-
http://www.norcom2000.com/users/dcim...erbolts01.html
or tiny-fied-
http://tinyurl.com/7hrwa9u

The first/top photo is an overall view of the door.
The replacement frame is highlighted in red, and the five rods holding
it in are shown by faint green arrows.

The second pic is a close-up of one of the plastic allthread rods, and
the (metal) nut and washer attaching it. You can see that the plastic
charred a bit from being cut with a power saw. The inside of the rod
(visible inside the freezer) is done exactly the same as the outside.
All the doors they fixed were done this way--with plastic bolts
(w/normal zinc-steel nuts & washers) holding the door frames in, but
metal bolts everywhere else.

???????

I thought maybe it was a safety-breakaway sort of thing, but these
coolers are constructed VERY flimsy. I'd give it about a 50/50 chance of
the nuts just pulling through. Is there some other reason, or is that all?

DougC fired this volley in
:


I thought maybe it was a safety-breakaway sort of thing, but these
coolers are constructed VERY flimsy. I'd give it about a 50/50 chance
of the nuts just pulling through. Is there some other reason, or is
that all?



It's because the plastic rods don't conduct heat. Therefore, they won't
get cold on the outside, and "sweat" (condense moisture).

Had it been done in a robust way, they'd have used phenolic or fiberglas
spacer rods, either self-threaded, or with pressed-in threaded inserts.
Then they'd have bolted them from both sides with metal hardware.

But it's not a shortcut or designed to be weak. It's to prevent thermal
conduction through the fastening system. They were just too cheap to do
it stronger than that.

Besides... I'll defend them some; if the rods are of the correct type of
plastic (say, annealed (or tempered) nylon, or acetal) and correctly
sized, they will be strong enough, even if not as strong as metal
fasteners.

LLoyd

On 1/10/2012 22:30, DougC wrote:
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door & latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

Less heat loss? Insignificant, yes, but..

Kristian Ukkonen wrote:

On 1/10/2012 22:30, DougC wrote:
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door & latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

Less heat loss? Insignificant, yes, but..
Not insignificant! The greatest cost in grocery stores after the employees
is the refrigeration. Maybe I misunderstood, it may even be GREATER
than the employees.

Jon

On 1/10/2012 15:30, DougC wrote:
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door & latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

See pics here-
http://www.norcom2000.com/users/dcim...erbolts01.html

or tiny-fied-
http://tinyurl.com/7hrwa9u

The first/top photo is an overall view of the door.
The replacement frame is highlighted in red, and the five rods holding
it in are shown by faint green arrows.

The second pic is a close-up of one of the plastic allthread rods, and
the (metal) nut and washer attaching it. You can see that the plastic
charred a bit from being cut with a power saw. The inside of the rod
(visible inside the freezer) is done exactly the same as the outside.
All the doors they fixed were done this way--with plastic bolts
(w/normal zinc-steel nuts & washers) holding the door frames in, but
metal bolts everywhere else.

???????

I thought maybe it was a safety-breakaway sort of thing, but these
coolers are constructed VERY flimsy. I'd give it about a 50/50 chance of
the nuts just pulling through. Is there some other reason, or is that all?

So you can bust out if accidentally locked in? G

--
Steve Walker
(remove brain when replying)

On Tue, 10 Jan 2012 14:30:57 -0600, DougC
wrote:

At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door & latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

See pics here-
http://www.norcom2000.com/users/dcim...erbolts01.html
or tiny-fied-
http://tinyurl.com/7hrwa9u

The first/top photo is an overall view of the door.
The replacement frame is highlighted in red, and the five rods holding
it in are shown by faint green arrows.

The second pic is a close-up of one of the plastic allthread rods, and
the (metal) nut and washer attaching it. You can see that the plastic
charred a bit from being cut with a power saw. The inside of the rod
(visible inside the freezer) is done exactly the same as the outside.
All the doors they fixed were done this way--with plastic bolts
(w/normal zinc-steel nuts & washers) holding the door frames in, but
metal bolts everywhere else.

???????

I thought maybe it was a safety-breakaway sort of thing, but these
coolers are constructed VERY flimsy. I'd give it about a 50/50 chance of
the nuts just pulling through. Is there some other reason, or is that all?

YOu may have answered it yourself. They're built so flimsily that
metal bolts would have pulled the nuts through without the worker
thinking about it. Plastic probably reduces that tendency. There is
also the possible safety feature of plastic. OSHA, in its many
splendored workings...

--
We are always the same age inside.
-- Gertrude Stein

On 1/10/2012 7:04 PM, Larry Jaques wrote:

???????

I thought maybe it was a safety-breakaway sort of thing, but these
coolers are constructed VERY flimsy. I'd give it about a 50/50 chance of
the nuts just pulling through. Is there some other reason, or is that all?

YOu may have answered it yourself. They're built so flimsily that
metal bolts would have pulled the nuts through without the worker
thinking about it. Plastic probably reduces that tendency. There is
also the possible safety feature of plastic. OSHA, in its many
splendored workings...

--
We are always the same age inside.
-- Gertrude Stein


Remember the latches on refrigerators - back before magnetic seals?

No way one could get out if the door closed.

Every walk-in cooler/freezer that I've ever seen had a handle on the
inside and a mechanism so simple as to be jam-proof. I.e., you couldn't
get locked in.

The cross-sectional area of 6 1/2" bolts is so much less than the
surface area of the cooler/freezer that it's hard to imagine that the
heat transfer would be significant. Not significant relative to the
loss from people going in and out all day long, either.

But then I can't think of any other reason. Corrosion-free comes to
mind, but that's what anti-seize is for.

Bob

On 1/11/2012 1:25, Jon Elson wrote:
Kristian Ukkonen wrote:

On 1/10/2012 22:30, DougC wrote:
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door& latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

Less heat loss? Insignificant, yes, but..
Not insignificant! The greatest cost in grocery stores after the employees
is the refrigeration. Maybe I misunderstood, it may even be GREATER
than the employees.

Just calculate the heat flux through a long piece of steel allthread..
I can promise it will not be that much..

The refrigeration heat loss from other sources certainly can cost a
lot of money.. Like the unshielded shelves for groceries/cheese etc..
Or the customers opening the doors to get the milk cartons/soda/beer..
Or the employees going in/out from the storage getting stuff..

On Wed, 11 Jan 2012 21:17:19 +0200, Kristian Ukkonen
wrote:

On 1/11/2012 1:25, Jon Elson wrote:
Kristian Ukkonen wrote:

On 1/10/2012 22:30, DougC wrote:
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door& latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

Less heat loss? Insignificant, yes, but..
Not insignificant! The greatest cost in grocery stores after the employees
is the refrigeration. Maybe I misunderstood, it may even be GREATER
than the employees.

Just calculate the heat flux through a long piece of steel allthread..
I can promise it will not be that much..

The thermal conductivity of steel is about 1100x that of fiberglass
insulation. So ten 1/2" steel rods would conduct as much heat as 15
square feet of insulation.

--
Ned Simmons

On 1/11/2012 1:17 PM, Kristian Ukkonen wrote:
....

Just calculate the heat flux through a long piece of steel allthread..
I can promise it will not be that much..
....

Well, by the time you multiply it by some number of separate pieces,
maybe it isn't so small after all.

Might as well save what can in the design process would be my thought
even though the folks designing the walkin coolers/lockers aren't tasked
w/ the overall store refrigeration loss calculation, they may as well do
their part in new gear. Plus, plastic is now probably cheaper than the
metal rod, anyway.

--

On 1/11/2012 22:22, Ned Simmons wrote:
On Wed, 11 Jan 2012 21:17:19 +0200, Kristian Ukkonen
wrote:

On 1/11/2012 1:25, Jon Elson wrote:
Kristian Ukkonen wrote:

On 1/10/2012 22:30, DougC wrote:
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this
was by taking the old door& latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

Less heat loss? Insignificant, yes, but..
Not insignificant! The greatest cost in grocery stores after the employees
is the refrigeration. Maybe I misunderstood, it may even be GREATER
than the employees.

Just calculate the heat flux through a long piece of steel allthread..
I can promise it will not be that much..

The thermal conductivity of steel is about 1100x that of fiberglass
insulation. So ten 1/2" steel rods would conduct as much heat as 15
square feet of insulation.

Ok, a few dollars a year based on a quick calculation of
heat flux trough a 10cm thick wall.. Perhaps still within
reason to use plastic if it is easy.

On 1/11/2012 22:29, dpb wrote:
Might as well save what can in the design process would be my thought
even though the folks designing the walkin coolers/lockers aren't tasked
w/ the overall store refrigeration loss calculation, they may as well do
their part in new gear. Plus, plastic is now probably cheaper than the
metal rod, anyway.

No harm in using the plastic. I have to admit, the loss was rather
bigger than I expected, when I actually calculated it..

Ok, I am a commercial refrigeration servicman so I will try to weigh in on
this one. It would not be the end of the world if steel were used and the
condensing unit was sized properly, other than the fact there would always
be ice on the bolts and a little puddle of water under the hinges. Most
commercial walk in boxes have foamed in place construction I.E. two skins of
sheet metal with urethane spray foam between. There is nothing there for a
screw or bolt to secure itself to. There is supposed to be a 1/4" plate
steel behind the area where the hinges are placed and threaded screws are
supposed to hold the hardware in place, with out penetrating the inside of
the walk in. Things happen to the plate etc. and drastic measures have to be
used to correct the problem. I like well nuts (expandable rubber covered
nuts) for situations like this. In your case they put a whole door/frame
skin assembly over the existing door and most likely caulked/silconed the
heck out of it. The plastic allthread is there for looks. You would have to
take a forklift and several prybars to get it to budge now. Where I work we
make our own walk in coolers with a two x four wood frames (not legal in all
areas per building codes). When a lag screw strips out we drill the hinge
hole a little bigger a go to the next larger screw or lag bolt or use well
nuts...........or put a new skin on with plastic allthread. :-)
Lyndell


"DougC" wrote in message
...
At the grocery store where I work, the walk-in freezer doors/doorframes
got banged up over time, so they fixed them.... The way they did this was
by taking the old door & latch off, and by putting a whole new door
frame+door inside the old opening.

Recently I noticed that the new frames are all held on by plastic
allthread rods. Why is this?

See pics here-
http://www.norcom2000.com/users/dcim...erbolts01.html
or tiny-fied-
http://tinyurl.com/7hrwa9u

The first/top photo is an overall view of the door.
The replacement frame is highlighted in red, and the five rods holding it
in are shown by faint green arrows.

The second pic is a close-up of one of the plastic allthread rods, and the
(metal) nut and washer attaching it. You can see that the plastic charred
a bit from being cut with a power saw. The inside of the rod (visible
inside the freezer) is done exactly the same as the outside. All the doors
they fixed were done this way--with plastic bolts (w/normal zinc-steel
nuts & washers) holding the door frames in, but metal bolts everywhere
else.

???????

I thought maybe it was a safety-breakaway sort of thing, but these coolers
are constructed VERY flimsy. I'd give it about a 50/50 chance of the nuts
just pulling through. Is there some other reason, or is that all?

My grand mother in Ohio had one of those. With grand kids around, lucky no
one got hurt.


Christopher A. Young
Learn more about Jesus
www.lds.org
..

"Richard" wrote in message
m...

Remember the latches on refrigerators - back before magnetic seals?

No way one could get out if the door closed.

I have seen coolers for ice cubes that were outside of gas stations where
the door latch area was all covered with ice and frost. I think I have seen
older freezers/refrigerators where the latches had corroded badly on the
outside, presumably from constantly being damp.

Plastic bolts, if strong enough, sure sound practical to me.

Pete Stanaitis