Mercury Manometer

[toastedhead]

Does anyone know where I can get some mercury to refill my manometer?

 

[drawoh]

Inches of water /= inches of mercury

I wanted to measure pressure differences of around 0.1"[ ]H₂O. This would have been a challenge with mercury. Converting from mercury to H₂O might be fairly easy depending on your pressures, but you would still have to dispose of the mercury.

My point was that I made a pressure gauge out of cheap stuff I bought at a hardware store. If I can find mercury, I can make a mercury manometer.

JHG

 

[Compositepro]

Drawho, dilute your ammonia and give it to the janitor. It would be foolish to dispose of it as hazardous waste when you can buy it in the grocery store to clean floors.

 

[ScottyUK]

jmw,

Just start using 150W lamps and connect a 1N4007 diode in the live lead to half-wave rectify the mains and drop the wattage a bit. The lamps last much better. It introduces a DC component and loads of harmonics into the distribution system but more importantly it gets around the stupid bloody rules made by stupid bloody politicians in Brussels who have nothing better to do with their worthless lives than interfere in ours.

/rant!


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[jmw]

http://www.telegraph.co.uk/news/matt/

JMW

http://www.ViscoAnalyser.com

 

[hacksaw]

Hg is hazardous and should be treated with caution.

Absorption through the skin is minimal, but the vapor pressure of Hg is such that it is harmful without proper ventilation. The hazard is that spills generate enourmous droplet fragments that are nearly impossible to recover except in a lab environment. The soluable Hg compounds are another matter entirely.

There are other high gravity liquids that can be used, not as handy as Hg, but easier to manage. The best bet is to use a proper transmitter.

 

[btrueblood]

"Drawho, dilute your ammonia and give it to the janitor. "

Or pour it on the lawn.

 

[HDS]

Hacksaw

"There are other high gravity liquids that can be used, not as handy as Hg, but easier to manage. The best bet is to use a proper transmitter."

What are they and do they really work? Many of the other other liquid metals wet glass and can't be sued in a manometer.

Toastedhead

Where did the Hg go? Why do you need more? If it evaporated there is a safety concern because Hg Vapor is the real hazard.

Whoever made the manometer should sell Hg. A google search for distilled mercury will get you several vendors.

 

[TheTick]

OP has been silent w.r.t. the application for the manometer. Is he just restoring an antique?

 

[Compositepro]

Out of curiosity I checked Dwyer's products. They do not make mercury manometers. They make manometers for measuring low differential pressures, not absolute pressures. You can fill their fluid manometers with whatever fluid you choose, typically water or oil.

My mercury manometers were made by Princo Instruments. They do not make them anymore.

 

[oldfieldguy]

That was the nice thing about manometers: Anybody could bend a tube and fill it with a fluid and you could measure pressures with a simple scale (ruler). No muss, no fuss, no calibration, no "we need to add A/D conversion, serial an wi-fi comms, programmable scaling, etc., etc.," ad infinitum.

Life was so simple for us dinosaurs.

old field guy

 

[toastedhead]

Yo compositepro. In the directions for the Slack Tube manometer it states mercury can be used and they have it available - but I inquired about it and they specified they no longer carry it.

The slack tube was dropped and the mercury ran out.

Im moving to electronic from now on.

 

[KENAT]

"The slack tube was dropped and the mercury ran out."

Don't let any lawyers or OSH type folks see that!;-)

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[toastedhead]

Tell me about it. I went to the back to check up on some stuff and asked about the slack tube. "Oh we dropped it. We cleaned it up though."

"How?" I asked knowing that I didnt want to know.

"With a broom and a dust pan."

 

[KENAT]

Wouldn't that be the very poster child for why not to use it wherever possible then?

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[unclesyd]

On all our slant tube manometers we used "Red Instrument Oil". in place of water.

http://www.grainger.com/Grainger/it...ments-_-Pressure and Vacuum Measuring-_-1TC00

You fellows haven't been exposed to any mercury at all. Like everyone else with a little age we all have played with mercury in school. I was ok until I killed my mother's wedding band. Mercury was used in the gas meter at my house. Mercury was all over the college labs. When I started to co-op we had mercury all over the place, even the Orsat apparatus had mercury as the controlling fluid. When I started to work after school we had Hg manometers for gauging tanks in the control rooms, 30 in 1. On the distillation side we used Hg manometers in the contol rooms for column differentials. In a nearby paper mill they had all live instruments in the boiler control room so when a Hg instrument losted it fluid it probably fell on a hot steam line.

Mercury was extensively used in medicine at the time.
Calomel- ingested for everything that ailed you.
Yellow oxide of mercury-Used for infections especially the eyes.
Ammoniated Mercury-used in all types of ointments for external use.
Bichloride of Mercury-used to kill everything.
The Pharmacopeia of the time listed over twenty mercury compounds used in medicine.

 

[rmw]

I have used plenty of mercury and water U-tube manometers back when I was a younger engineer. Recently I had to verify that the gas pressure in my home was some certain value and I have long since lost my old manometers so I made one out of some clear plastic tubing (and some green food dye to make it easier to read-green was all the wife had at the time) to troubleshoot a troublesome tankless water heater. When the technician arrived he thought I was nuts and would only accept the reading he took with his digital instrument. It read what I had told them that the gas pressure was.

Speaking of mercury, what about the old kidney type pressure and differential pressure transmitters. Bailey's, Hagan's, and others. I've seen plenty of times that the mercury was just poured out on the ground and then they were refilled with fresh. But then again, that was back when our kids were gnawing on window sills with leaded paint on them (as we did). So what did we know. Look at us and look at the idiots that society is producing today. I think we should bring the lead and mercury back and we should play with it riding around in the open bed of a pick up truck.

rmw

 

[KENAT]

Or maybe it's the long term effect of all that stuff catching up with us;-).

Like many things I'm sure the potential effects of mercury have been exaggerated, doesn't mean everything that used to be done with it was a good idea though.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[unclesyd]

The last mercury I saw purchased came from some place in Missouri. I called the lab where I use to work and they haven't bought any in years as what little they still use is refined in the lab. All their Mercury came from a Scientific supply house. As I understand it selling is banned in some states and some states you have to have a permit to buy, while a few offer no restrictions.


Leaded paint brought up another point that a lot of us grew up with, nearly all galvanized pipe joints were made up with white lead as the sealant. that included both water and gas. Mercury in the gas meter hooked up with lead in the pipe joints. A lot of farm buildings were painted with red lead based paints.
Where I grew up you couldn't have any white or light tone paints as the H2S in atmosphere turned the paint black in a couple of weeks.
The local creek has a film of coal tar creosote and phenol mixture and would periodically catch fire. It made a good dog dip as it cured everything, if the dog survived.
My father ran his 41 Chevy on 75% benzene + 25% gasoline during the war.
The gas metered into our house was water gas that had about 10% CO in the mix.
We didn't heat with gas, only cooked and heated water as we burned coal for heat so you didn't hang light colored clothes on the outside cloth's line.


I had a 25# tub of white lead oxide and created a big commotion when I carried it to the dump on one of the hazardous waste amnesty days.

 

[btrueblood]

" I think we should bring the lead and mercury back and we should play with it riding around in the open bed of a pick up truck."

With or without helmets and pads?

 

[bnrg]

Most fillings in your teeth use amalgam which contains several % mercury.