How Mechanical Seals Work - stuffing box - packing
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- Опубліковано 26 жов 2021
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The mechanical seal is a device that is capable of isolating two environments, where between the two is found a component (like a shaft) with a circular or axial motion.
Jaes, for over a decade has been providing its customers with the best solution for their supply chain and in its catalogue catalog every kind of mechanical seal from the leading manufacturers
Mechanical seals are used in almost every hydraulic machinery, to understand their operation we will take as an example a classic centrifugal pump, in which a shaft connects the motor to the impeller.
The mechanical seal is placed on the backplate in order to contain the fluids that are inside the pump, which otherwise would draw from the space between the backplate and the shaft, helped also from the internal pressure. In this case, the backplate acts as a stationary housing, while the shaft is the rotating part; the mechanical seal will have to be able to hold the pressure during the pumping and to resist the friction caused by the shaft rotation.
One of the old methods to guarantee the sealing that is still widely used, is to employ some stuffing boxes, a system that can keep tight around the shaft, a material similar to the packing (a twisted wires rope).
However, this method has some relevant flaws, in fact in order to work properly, it has to be pressed against the shaft. This method implies several problems: a huge wear of the packing, its periodical maintenance, the necessity to use great quantities of water to cool it down because, while making friction, its temperature, the consumption of the parts in contact with it and even the wasted energy from the motor to win the friction force, they all increase
That’s why mechanical seals are replacing old methods day by day, since they are designed more and more, which are projected to remedy these disadvantages.
The most common mechanical seal has three sealing points.
The stationary part is fixed to the backplate of the pump with a sealing gasket between them.
The rotating part is, instead, fixed to the shaft with a seal between them as well, in this way the rotating part rotates is integral with the shaft.
One of the two parts(in this case the rotating part) possesses one moving element that is firmly fixed and pushed from a spring; this one presses against the permanent part creating the last sealing point.
This moving element follows the shaft movements caused by the bearing “game”, the misalignments caused by the production tolerances, and from the thermal expansions during the functioning.
The seal between the rotating and the stationary part is the element that the mechanical seals have in common.
As you can guess the two parts are in contact with each other, and the rotating one frictions on the other during the rotation. For this reason the faces of the two parts that are in contact are made of flat surfaces worked with extreme precision and smoothness.
Besides, the pressure inside the pump, combined with the centrifugal effect obtained from the rotating part rotation, cause a fluid film to be created between the faces in contact, made from the same fluid pumped from the system, that while lubricates them also prevents direct contact. This lubricant foil can also be introduced from an external source.
In this way, the mechanical seals can isolate the internal pump room from the external environment, despite the presence of the rotating shaft.
If you are interested in discovering the many types of mechanical seals, watch the videos in our playlist.
If you’ve found this video useful, let us know that by leaving a like and a comment, you can also share it, and don’t forget to subscribe to our channel.
We suggest that you visit our website jaescompany.com to find out more about our next projects. - Наука та технологія
I’m 38 years old watching a random video about mechanical seals and I got the most wonderful cozy feeling. I asked myself why I love stuff like this (went to school for automotive engineering, love to build anything etc) and the answer has always been clear: My grandfather was an engineer/technician for General Motors, made the machines that made the cars. A tool maker.
He lived just outside of Detroit and my horrible single mother would send me there every summer growing up so she could take vacations with her friends. I grew to love it, and my grandfather, very much. In retrospect, he’s the only person that I think really loved me as a kid. I know my mom/stepdad didn’t. I guess it’s only natural that he would imprint so deeply on me. Those six summers before he passed affected me more than my first 18 years. I have even caught my mom watching me with a tear in her eye when I used to live back home and she caught me out in the garage going through his old tools but he passed down to my bitch made stepdad, polishing up the nice Swedish made wrenches and other tools from mid century America and Europe. She said I was just like her dad; could spend hours just cleaning up and organizing tools….
Anyways, I was watching this random promo video for mechanical seals from some faceless corporation and I thought “Gee, I bet Grandpa Willy would love to watch stuff like this, he would get a real kick out of it, being able to see machine parts working and in motion on computer simulations and all that stuff, I sure wish he was around”
And then I realized he was, because I am so much like him. Kind of felt like he was sitting next to me on the couch too. Then I realized for the first time since I got my dog almost 3 years ago that he looks exactly like my grandfathers dog when I would go to visit. His name was Jet, a huge black lab, grandpa Willy’s hunting companion, and now I have a black lab great Dane mix named ᛋaxon.
Anyways faceless corporation, thanks for the promo video, it gave me a couple cozy minutes, and about a half hour of reflecting and typing this message out. It’s the little things in life. We both enjoyed it very much 😉
Bellissima storia. Un forte abbraccio dall'Italia
That was a lot of tangentially-related introspection for just a 4 minute video
Your passion for machine & technical things is like our Indian maharashtrian people especially old people. Blessings from India 🇮🇳
You make me proud son. You have grown into a good man like i always knew you would.
- Your Grandpa Willy would have told you this.
i ended up being a professional installer for all kinds of crazy pumps. same thing. tragic story. great grandpa and grandpa were engineers but society has fallen etc etc
i really enjoy this kind of stuff. instead of a green thumb for gardening i like to say that i have a gray thumb for all things craftmanship related (electronics, mechanics etc) im 36 years old btw at the time of this writing
Thanks youtube ... this had been a long standing and pressing curiosity
Same here, I never could figure out how they sealed rotating shafts when holding back high pressure fluids.
Further read about API682 mechanical seals piping plans to know how different arrangements of piping and related equipment are used to provide the pressurized lubricating film in between the rotating and stationary part of these seals. Also read about Dr Gas Seals which are widely used in heavy equipment like centrifugal compressors dealing with natural gas as process fluid.
I work as a maintenance engineer in a chemical company. There are many types of mechanical seals in the chemical reactors of our company. Your film is very useful to explain the concept of mechanical seal to apprentice in chemical engineering.
I work in a oil refinery and operate many pumps like this. We have moved away from that stuffing box type of seal to a seal pot (filled with barrier fluid). Great video!
Can u give me ur account in any platform? i’m a new operator and I have questions that I want to ask u
Not only has the Deutz diesel engine on my stump grinder, run, and not leaked, for over 25 yrs, but, the 2 Eaton hydraulic pumps of the same age, have thousands of hrs, and never leaked. I am amazed.
Don't ever stop making such videos, JAES!!
The best channel
thanks you Damcho where are you from ?
1. For a common centrifugal pump the rotation of the shaft should be clockwise as viewed form the motor.
2. One seal face sould be slightly concave to compensate for thermal distortion as the seal runs and heats up.
Ok Mr. Genius!
100% agreed with you.
Maybe you could make your own videos!
Not so sure about #2. Seal faces need to be flat. If there are temperature concerns there is an inlet from the gland plate that serves to lubricate the mating surfaces. The rotary element is usually a softer material than the stationary element under a fixed load that pushes against the stator as it wears. The reason that fire trucks use packing rather than seals is that seals can break and leave you high and dry in a possible emergency.
I work for a sanitation district and we have a handful of these mechanical seals on our waste water pumps. In the stations that have issues with grit like sand coming into the wells from the influent line, these mechanical seals dont like it. Periodically have to be taken apart and have the seals replaced. If the station doesnt have a grit issue then they work fantastic, you just have to dial the flow through them precisely.
Are you in California ?
@@xxxdpgxxxx1389 no
@@chefdan87 what to expect for a mechanic, got a job offer in the sanitation district in apple valley, really good pay government job.
Thank you for this simple and insightful video about mechanical seals. This video is very useful to understand the mechanical seals and its applications.
Ótimo explicação! Great explanation!
A brilliant video, thank you so much 🙏🏼🙌🏼
Im an engineer in a dairy factory. Our aseptic pumps use carbon seals. With high temp water barrier seals
Marvelous Animation with full explanation. thanks for sharing.
How could I not sub to this kind of quality animation and explanation? Good job!
Beautifully explained. Thank you.
The animation is superb....
Totally did find it helpful. Thanks!
Thank you progressive technology
Question... during operation, in the video it states that the two surfaces (stationary and rotary) don't come into contact, but are separated by a film of water or whatever is being pumped, how is that fluid stopped from getting past the two half of the seal and leaking through the back of the pump/seal?
Thanks for very useful video!
Great video👍👍
Great animation, keep up 👏🏽👏🏽
Thanks you sir where are you from
Thanks for the information
TQ sir please upload this type of automobile video more n more . We support u.
Very useful video
Awesome video
Very clear understanding
well explanation, thanks a lot
great video. thanks
Yes this really a useful video
Wow, that is really cool.
Great content 👍🏾
Started new job rebuilding pumps very helpful thanks. Gotta love youtube
don't touch the seal faces with your fingers or sweat nor use any foreign lubricants. spit or water is prolly the best lube to use fitting the seals
Great video and useful
thanks you King
Great video
Well Done.
Its a suitable vedio for understanding.
Very interesting 👍👍
Thanks sir. Inspiring
Didnt know i needed to know this
Thank you
Best video of MS
Neat concept. I like this.
Thanks!!
thanks!
Thanks for sharing
thank you
Great video and explanation. Subscribing
Excellent.😎
Nice video
Good video
very useful information
can it possible to change from packing to mechanical seal on existing pump
Of course. Depends how much you want to spend.
My curiosity has been quenched
I know the plan 11 flush pressure at suction is = Pump suction pressure +0.5bar. But how to calculate the plan 11 flush pressure at pump discharge side?
Thanks 👍 very very nice 👍
I love learning
good explination !
thanks Jonas
good video 👍
thanks you
great
Looks like a perfect seal for production engines and most definitely racing applications. Ok Jaes that is a million dollar Idea i raced for 33 years and built my own engines for 45 years. God bless have a great day. Also awesome video!
thanks you Joe feel free to advise us where are you from?
So, I am working on this pump and it has the packing right off the pump. The shaft then runs through a cast casing with a bearing on each end. And according to the drawing the mechanical seal is in between the bearings so to change it I have to press the shaft out. Why is there a packing seal and a mechanical seal a few inches further down the shaft?
Great
Nice
So the seal is lubricated by the pumped fluid or external fluid (seal water). What about flushless cartridge seals that pump dirty fluids?
It is useful animation. Thank you... Could you please can you explain how it is working water seal two stage vacuum pump
we will work on it in the future where are you from Abdul ?
so how to pump an agressive fluid ?
How the moving part in the seal is attached to the shaft?
Today I saw a water pump leak at the area of shaft, suspected the mechanical seal leak, does the mechachnical seal leak can cause the Air enter the pump system?... There are two pump operating to serve in the same header outlet pipe, the good pump outlet pressure is 0.5Mpa,while the mech seal leak pump outlet pressure is 0.4 MPa.
Hello, very interesting video. But what about when the medium that must be pumped is sand slurry? Is is still efective? Cos we has some pumps in our AAC factory and mechanical sealing broke very often. The sealing is cooled by water from a reservoir. This reservoir came with the pump.
On board a ship we had a pump was have to pump mud and similar erosive substance, the air seal was used. Compressor constantly supply some air to be like blown into through the seal, tiny amount but worked with no issues at all.
Problem is that our mechanical sealing is flushed with water to cool down. We cannot add compressed air. And if we use air is not going into the pump and wil cause cavitation?
@@bladerunnerro Appears the pump manufacturer might be using a mechanical seal that is unable to handle your service requirements, or at least you need to upgrade the seal specs. The reservoir might be used for flushing as much as cooling. I'd suspect you need harder mating surfaces, such as a tungsten or silicon carbide mating surfaces. I have 10 years experience in sales and service, but that was many years ago now. You need a seal recommendation, and I'd bypass the pump manufacturer entirely for this. Mechanical seals are not cheap, but downtime is wasted money, too.
Thnka
What about small components?
hi can i use in my website?
What material do you use ? Ptfe, Tpu or ??
must be much harder. graphite and hardened steel or silicon carbide / silicon carbide
Parts of the seal shojld hv been separately shown and described
Sir please make a video for grundfos multistage pumps...
hello thanks you for advise we will work on it
Main products: sealing gasket,gland packing,PTFE/graphite/asbestos products, ceramic fiber products, high temperature heat insulation and fireproof material.
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So what prevents the leak between the sprung seal and the shaft itself?
o-rings
@@gordonmutch8086 Strange they didn't show it, I would assume the actual shapes of the components are different from what is shown here
We made Vacseal pump..
Please I need to order those stuffing box packings. I go into your website and I'm wondering how to find them or a reseller
Fire pumps leak on purpose
I repack them often
And the animation has the shaft rotating the opposite rotation for this case
Edit: it is correct at 1:40 but incorrect at 4:08
thanks you Jake we will check
So the actual seal is the gasket and fluid film not the metal to metal surface …
Cool - what are the two in contact materials made of?
I think a graphite material. I haven't changed a mechanical seal for a few years though......
I think the one I worked on was ceramic
@@rayzerot that sounds familiar.....
That's good job and I like it but my problem it's money for training am doing this job from 2011 until today and if I can a better job giving me money I can get certificate
I am wondering that what does "seal gas" mean ? why do we use for the pumps ? Secondly why the pumps have "primary and secondary seal gas in" ? What is the difference between primary and secondary seal gas in ? Would you make it clarify for me those questions ?
Graat
Diamonds can cut diamonds. Diamonds can cut sapphire. Sapphire cannot cut diamonds.
BUT SAPPHIRE CANNOT CUT SAPPHIRE! Wait a minute! My granduncle taught me this which was passed on to him by his teacher in mechanical engineering and he in turn passed it on to me. As for lubricants we use medical grade castor oil mixed and dissolved with processed fish oil and mixed and dissolved with molybdenum disulfide. Castor oil creates a self-renewing varnish like coating on moving mechanical surfaces, fish oil allows deep penetration against rust and especially penetrating very hard rust, molybdenum disulfide allows extreme lubricity. FLEXIBLE Graphite is also useful as a revolving seal material when used against each other for graphite lubricates itself also.
Circular action is radial. Not axial
oil fed mecchanical seals from the back are better
There is no Arabic translation available
Sería muy bueno traducción a español😅
Hola tenemos canal en espanol Jaes espanol se llama
👍
But will it pump beer 🍻
Every seal cannot escape contact between moving and stationary part.
? Yeah they showed the contact point. And they showed how it was partially mitigated through the fluid film layer
How does...the terminology...even can has...a meaning?!
what speech synthesizer software do you use to create these videos? Could you not ask a real person to read the script? It would avoid you the many mistakes that are present in your videos.
IZIN DOWNLOAD
Now, I'd like to disarm it by myself
Would help credibility if there weren't frequent grammatical errors and bad word choice.
I wasted my time
Incoherent