بایگانی ماهانه: آوریل 2020

Can I leave a vacuum pump running overnight?

I wandered into the lab one Saturday morning while I was in graduate school – (OK, scratch that, I wandered into the lab most Saturday mornings while I was in graduate school, which was one of the things I hated about it.) And as I walked past the vacuum pump, I noticed something a little odd.
For those who don’t work in a synthetic chemistry lab, the vacuum pump is where you put flasks of stuff after you’ve evaporated most of the solvent off of them. The pump pulls the last volatiles residues out of your syrup, crystals, or powder, leaving you with a dry weight that you can use to check your reaction yield, get pure spectra of the material, and so on.
The pump was making a different sound than usual. There was more of a rattle in it this morning, and less of a hum, if that makes any sense. I looked the thing over, trying to see what was going on, and finally I checked the row of stopcocks. Pay dirt! One of them was wide open, and the reason the pump was making that unusual sound was that it was trying to pump the air out of the entire chemistry building.
That isn’t good for them. And in an academic lab, it’s not like you could just reach into a cabinet and pull out another vacuum pump when you burned one out. They aren’t cheap, and we spent time fixing the ones we had rather than attempt to ever buy new ones. So I twisted the glass stopcock closed, muttering foul gerunds, and left an unpleasant note taped to it. Something about how if you were the last user of this pump, you left the procreating stopcock open, and you shouldn’t reproducing do that, etc. And I went about the rest of my merry morning’s work.
The next morning, I wandered into the lab yet again. (I was there most Sunday mornings, too, damn it all.) And as I walked past the pump, I could swear that something was odd yet again. Surely not. I went back, looked it over, but couldn’t see anything out of whack. Then, hardly believing it, I moved my taped note back to find the same stopcock, left wide open again. The slackjaw that did it it had to hold the note up to get to the stopcock, which really defied belief. There was the poor vacuum pump, trying to evacuate the air out of the state of North Carolina again.
I went stomping through our labs, looking for the culprit. But I was the only person there. No one in my group had done anything like that, so I wondered if someone else had been in there. . .then I remembered a Moroccan biochemist from another group who came over sometimes to hang out with the guy around the corner from me. Maybe. . .I went over to the next hall, and there was the pride of Marrakesh himself, humming tunelessly as he wandered about his lab.
So in I went, demanding to know if he’d been in our lab that morning, used our vacuum pump, and so on. He gave me a big grin: “No, I have not used this pump. But I have gone past it this morning, and I have thought, Hmmm, she is sucking ze air, no?” My testy reply was that if I found out that he’d been leaving the pump open then he would be sucking ze air, yes. For whatever reason, our apparatus went unmolested after that.

How do you make a vacuum cleaner reactor?

The Swedish Nuclear Safety Authority has threatened to withdraw the operating license for the plant, the largest in the Nordic region, over what it says are two and a half years worth of safety warnings and special supervision from the safety authority that have gone ignored or unimplemented by plant management.

The fire represents the second since 2006 at the Ringhals plant.

A fire late last month at Oskarshamn, another Swedish nuclear power plant, had already cast a pall over Sweden’s safety record in the post-Fukushima world, and has put environmentalists on edge.

The May fire broke out in Ringhals’ reactor No 2. Ringhals is on Sweden’s west coast near the city of Gothenburg and is the largest nuclear power plant in the Nordic region.

Investigators said over the weekend that the fire at the reactor had been caused by a wet vacuum cleaner mistakenly left behind.

“Those items aren’t supposed to be left in the containment, when testing,” said Peter Gango of Vattenfall, the utility that runs the plant, in remarks to SVT Swedish television.

“It was a human error, and those shouldn’t occur in our power plants.”

Bellona’s executive director and nuclear physicist Nils Bøhmer also pointed out that a nuclear facilities are only safe so long as workers don’t make “stupid” mistakes.

“This incident once again shows the importance of the human factors in any nuclear installation,” said Bøhmer.

“You can build in a lot of safety equipment to prevent an accident, but the workers at that plant are only humans and will make stupid mistakes.”

At present, all of Ringhals’ four reactors are not operating, according to SVT. The power plant’s management hopes to get two of the reactors started next week, the television report said. The Ringhals facility supplies about one sixth of Sweden’s electricity.

Sweden’s the Local reported the fire-damaged reactor was scheduled to come back online in December after repairs had been completed.
Nuclear safety authorities weigh closure option

But Leif Karlsson, who heads the Swedish Nuclear Safety Authority’s radiation protection seemed to hint that restarting the reactors at Ringhals may be premature.

Karlsson would not say how close a closure of the plant may be, but he told SVT that “there is obviously a discussion that needs to take place if safety measures at Ringhals do not have the desired effect.”

“There may come a situation where we simply say we do not trust Ringhals to run the Business,” said Karlsson, adding, “and they do not” – a clear nod to Vatenfall.

Closing Ringhals would come as a sensational swoop from regulators in Sweden where it was decided just last that the country would abandon plans to phase out nuclear power. Sweden operates 10 nuclear reactors at three plants.

If Ringhals is not closed, reported SVT, it could fall under at least three years of supervision and mandated reorganization from the Swedish Nuclear Safety Authority – a record length in Sweden for such a governmental supervisory role.

The safety authority’s Eriksson said closure of the plant would be weighed on the basis of whether closing Ringhals was the correct approach, or whether more heavy-handed guidance of the plant would be successful.
Second fire in five years

The May fire was the second fire to occur at Ringhals in 5 years. In November 2006, a late night fire started at a transformer at reactor No 3 at the plant.

Reactor No. 3 unit is a pressurized water reactor that started commercial operations in 1981, according to the Ringhals plant’s Web site.

The fire – is as typical for such reactors – triggered an automatic shutdown and there was no danger to the reactor. There was no danger to the reactor, Vattenfall authorities said at the time.
Other recent nuclear mishaps in Sweden

The October fire at Oskarshamn was caused according to its operator OKG by oil that leaked onto a hot surface. The fire occurred in the turbine hall of the plant’s reactor No 2 and was quickly put out by the plant’s own emergency services, after which the reactor and the turbine were closed down as a precautionary measure.

The fire touched off fears in Northwest Russia of a possible spread of radiation, where specialists were quick announce on Sunday that background radiation levels in the Leningrad Region and in the city of St. Petersburg remained normal.

Other incidents have plagued the Swedish nuclear industry, often extolled for its safety, since 2006. In that year, a serious fire at Sweden’s Forsmark nuclear power plant threatened the integrity of a reactor.

In October 2008, fractures were found in the control rods of Oskarshamn’s reactor No 3, which led to a long maintenance blackout. Swedish Radiation Safety Authority called at the time for immediate inspections at Swedish plants sharing similar control rod designs. Inspections at Forsmark 3 revealed similar problems to those at Oskarshamn.

Earlier that same year, Oskarshamn became the centre of a security scandal when it was found that two subcontracted maintenance workers had gotten past checkpoints with a bag containing residue from explosives.

The two workers were released the next day, but suspicions about where the explosive residue had come from remains.

The incident provoked outrage from German Member of European Parliament Rebecca Harms who deplored the incident as showing up lax security at nuclear power plants.

How do you make a vacuum cleaner reactor?

Why is my vacuum pump smoking?

Are vacuum pumps supposed to smoke?

When you add a new piece of equipment it is wise to do some research into how it operates and what you can expect from it by way of noises, smells and discharges. Top of the list of concerned calls is smoke coming from vacuum pumps.

In many cases, the smoke you see is mechanical pump oil vapour. It is easy to assume that whenever there is smoke being emitted from the pump, it means there is something wrong with the machine. Oil vapour or oil mist is a natural by-product of creating vacuum in an oil sealed mechanical pump. As well as lubricating the moving parts, the oil is used to seal the fine clearances in the pump. While this high-speed movement of oil is excellent for stopping air leakage inside the pump, the oil flow creates a mist on the exhaust side of the pump.

Harrier are vacumm pumps supposed to smoke

Some designs of vacuum pumps contain an internal oil mist separator in the exhaust cavity. It usually remains closed with a cover plate. This part is made of a fibrous material that gets wet when oil passes through it. The more the oil passes through, the greater the chances of smoke discharge when the pump is operating in full throttle.

There are however some occasions when smoke can be an indicator of a potential problem. As the pump ages the oil mist separator can become clogged with contaminants. This will restrict the flow of air through the oil mist separator and increase the back pressure against the pump. This can cause damage to the seals and possibly the pump to seize. Oil mist separator elements should be replaced before they reach this stage

Another sign that smoke is a problem can be abnormal noises from the pump. If foreign objects get trapped inside the pump you might notice heavy smoke from the oil reservoir. There may also be erratic noises and vibrations and you may find the vacuum level slipping. This can be a severe problem. If you suspect there is debris or contamination in the vacuum pump, try changing the oil. If this does not improve performance get in touch with Harrier Pneumatics.

Something to watch out for is not overloading the pump with water. This will reduce its efficiency and increase the risk of a malfunction. An indication you need to check water level is a noisy pump and excessive smoke.

Understanding what you should expect from oil mist levels during operation can help you spot when something is amiss during operation. Addressing issues with excessive smoke or unusual noises as soon as they occur will help to extend the lifespan of the pump. Harrier Pneumatics have been selling, installing and servicing air compressors for over 25 years. Our Service teams will provide a regular maintenance and servicing regime to ensure your equipment performs efficiently. Get in touch to discuss your vacuum pump requirements.

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