What is stuffing box in centrifugal pump?
A stuffing box of a pump houses a gland that compresses the packing used to seal the pumped fluid. It prevents leakage along the shaft that passes through a hole in the pump. Stuffing box reliability is critical to the condition and performance of the whole fluid sealing program.
What are the three main parts of a simple stuffing box?
There are three main components to a traditional stuffing box: the stuffing box body, the compression sleeve, and some method of locking the compression sleeve in place.
Where is the stuffing box on a ship?
The Stuffing Box was a box that was built on the interior of the vessel around the shaft where it exited the vessel and it was stuffed with greased cloth and various other materials to keep the water out and also let the shaft turn at the same time.
What is in a stuffing box?
All stuffing boxes work on the same basic principle: Rings of special wax-impregnated flax packing are wrapped snugly around the prop shaft and stuffed into a hollow packing nut that is screwed to the outside of the stuffing box housing.
How do stuffing boxes work?
A stuffing box—also called a stuffing gland, packing gland or packing box—forms a seal between the prop shaft and the hole in the hull through which the shaft passes while allowing the shaft to turn freely. It consists of a threaded sleeve and a hollow nut, through which the prop shaft passes.
What are advantages of stuffing box?
Advantages of stuffing box
In case of any emergency situation packing rings inside the assembly can be easily replaced. It has only small leakage losses. The maintenance is simple and easy. It is easy to flush and lubricate.
How often should a stuffing box drip?
three drops per minute
Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning. Two or three drops per minute are adequate.
What is the purpose of stuffing box in marine engine?
The main functions of the stuffing box include the following aspects: (1) Preventing the piston rod from leaking dirt into the crankcase through the hole during the downward process, thereby contaminating the crankcase oil, corroding the crankshaft and connecting Rods and other components; (2) prevent the charge air in …
When should I replace my stuffing box?
While it depends on the number of hours a vessel is utilized, most powerboat owners should repack their stuffing box every two to three years. Sailboat owners (due to typically lower engine hours) should repacking every three to four years.
How tight should a stuffing box be?
Proper Compression. With all the packing rings properly seated, back off slightly on the packing nut (or nuts) and turn the propeller shaft five or six revolutions by hand. It should turn freely. If it doesn’t, the stuffing box is probably too tight and needs to be loosened a bit.
Can you repack a stuffing box in the water?
While it may be possible in some cases to repack a stuffing box with the vessel in the water, it’s a lot easier (and recommended here) to do it while the vessel is hauled. Experts recommend hauling any type of boat before servicing the stuffing box.
What is the importance of stuffing box?
In diesel engines , stuffing box is found in the bore for the piston rod in the bottom of the scavenge air box. The stuffing box prevents the entry of lubricating oil from the crankcase into the scavenge air space. It also prevents the leaking of air from scavenge space to the crankcase.
How often should you repack your stuffing box?
every two to three years
While it depends on the number of hours a vessel is utilized, most powerboat owners should repack their stuffing box every two to three years. Sailboat owners (due to typically lower engine hours) should repacking every three to four years.
How warm should a stuffing box get?
Ultimately, the arbiter of correct stuffing box adjustment is temperature rather than drips per minute. Once properly adjusted, the stuffing box should leak little and be no hotter than about 30°F-40°F above ambient water temperature.
What component is at the top of a stuffing box?
A metal insert ring fits on top of the stuffing box and is used to adjust or tighten the packing down to minimize water leakage. It is called a packing gland. Since the packing rings touch the shaft sleeve as it rotates, friction and heat are generated in the stuffing box when the pump is running.
How much should a stuffing box drip?
Water is required to lubricate conventional packing, so a properly adjusted stuffing box can be watertight when the shaft is stopped, but it must drip when the shaft is turning. Two or three drops per minute are adequate.
How many packing rings are in a stuffing box?
Most stuffing boxes are designed to accept three rings of packing. The joints should be oriented 120° apart from each other. The packing nut should be made snug, not much more than hand tight initially.