stuffing box corrosion

Mechanical seal leaks excessively 14. 6. While it may look ordinary, the hose used with conventional stuffing boxes is, or should be, proprietary. Ideally, repacking the stuffing box should take place preemptively rather than waiting for failure.  Taking this approach means the task can be carried out while the vessel is hauled for seasonal storage or bottom painting, although if necessary it can be accomplished while afloat.  While the frequency with which repacking takes place varies, one thing is certain, if, because of chronic leakage, the stuffing box requires repacking on a frequent basis, then it’s an indication of another problem, likely an issue with the shaft’s surface, it may be corroded, water flow may be impeded, or the packing installation or adjustment technique may be flawed. Corrosion resistance sulfur jar mandrel; stuffing box and other products, whose corrosion-resistant and Wear-resistance have reached the international advanced level Corrosión mandril resistencia tarro de azufre; prensaestopas y otros productos, cuya resistente a la corrosión y resistencia al desgaste han alcanzado el nivel avanzado internacional More than that amount (say 10 drops per minute) or drips while the shaft is not turning indicates the need for adjustment and/or maintenance. After gathering mounting anecdotal evidence that the shortage is reaching crisis mode, the MRAA decided to compile data regarding the situation.  After releasing a report detailing how widespread the problem was, the group is now issuing the results of its compensation survey — the first of its kind in the marine industry. In those cases T-bolt clamps may be required.  However, if T bolt clamps are used avoid the variety that relies on a folded, spot welded design, as these are susceptible to crevice corrosion. Packing should be cut at a 45° angle to provide a leak-resistant lap joint. This stuffing box leak detector is of simple construction with corrosion resistant parts. The same is true for stainless and aluminum stocks: chronic leakage is often an indication of corrosion at the packing. If necessary, this entire procedure can be carried out while the vessel is afloat.  Once the packing nut is removed simply secure several wraps of a rag around the stuffing box where the shaft exits to temporarily stem the flow of water.  Water will leak during reassembly; however, provided you work quickly it will be comparatively little. While I’ll share that editorial in its entirety once it’s printed, it is destined for the marine industry, and I’d like to give this subject broader reach.  This excerpt,  from an article published a few days ago in Soundings Trade Only, another industry publication, sums up what I believe is a potentially bleak scenario. If you have this problem, it's ultimately a question of how many new shafts do you want to buy before you replace them with better quality. Chronically leaking stuffing boxes lead to more than just wet bilges.  These clamps are seriously corroded as a result of regular exposure to seawater. Please also view our Upcoming Events webpage. Although some stuffing boxes are rigidly mounted to the shaft log, where they serve as a pseudo shaft support, most ‘float’ via a length of flexible hose, which is retained to the log at one end, and the stuffing box at the other end, using hose clamps, typically two in each location. Most packing consists of a square plaited material and comes either as traditional greased (or waxed) flax, or a more modern version impregnated with Teflon. Stopfbüchse aus Messing mit Abstreifring und doppelter O-Ring-Abdichtung aus EPDM. A leaking stuffing box can cause a number of issues, from corrosion (the spinning shaft slings excess water all over your engine compartment) to sinkings, particularly if the boat is left unattended in the water for longer periods of time. Conventional Wisdom for Conventional Stuffing Boxes, Laying up Potable Water and Sanitation Systems. Sorry, you have Javascript Disabled! What are the consequences of this leakage? The stuffing box seal assembly defined in claim 3 wherein said corrosion-resistant metal is a stainless steel. Capt. If a bronze stock rudder is chronically leaky, disassemble the stuffing box and check for excessive wear. Avoid such problems by simply replacing the packing on a regular basis. “We went through a whole campaign cycle [to elect] our nation’s president, and they were all talking about job creation. When a stuffing box starts to leak excessively, you should tighten the packing nut until the leak stops. DOuBLE PACkED STuFFINg BOx “BS” BODy ASSEMBLy TOP CAP uPPER PACkINg RINg CONE PACkINg (1) SET BODy LOWER PACkINg RINg 5/8"-11 x 2-1/4" FLANgE BOLT & NuT/WASHER (6) BASE COMPRESSION SCREW (2) gLAND NuT gLAND PACkINg (2) O-RINg COMPRESSION RINg … It is important that the polished rod be protected to the fullest extent possible from the corrosive effects of the fluids being pumped. Dutch windmill water pumps were among the first to use stuffing boxes. Unless instructed otherwise by the stuffing box manufacturer, three new rings of packing material should be cut, their inside diameter matching exactly the outside diameter of the shaft; the ends of each piece of packing should be cut on a forty-five degree angle so they mate in an overlapping fashion.  I find it helpful to apply a coating of high viscosity grease (I prefer Lubrimatic’s green Trailer Wheel Bearing Grease) to the packing sections as I install them, this acts as a lubricant and it helps keep the sections in place as they are inserted into the stuffing box recess or nut carrier. Mechanical seal has short life 13. Stuffing box made of brass with wiper ring and double O-ring seal made of EPDM. Do Twin Sheets Better Control the Mainsail? If, however, the packing has served well for an extended period, and is simply worn out, and needs to be replaced, the procedure is as follows. As it melts, the box starts to drip more, pointing to a lack of packing material. Good propeller shafts don't break because they don't corrode. . Enter a marine trades apprenticeship program, one that I believe would produce a steady flow of well-trained, vetted, enthusiastic professionals to fill this ever-widening void.  Such a program would raise the standards, thereby ensuring greater satisfaction and cost effectiveness for boat owners, which would in turn increase boat ownership ranks, something the marine industry has rightfully been wringing its collective hands about for a decade.  Furthermore, I would argue that the higher skill level that results from an apprenticeship program would in fact drive down the cost of boat ownership, as diagnosis would occur more quickly and repairs would be carried out correctly, the first time.  As I say in the closing lines of the editorial, “We as an industry need to take matters into our own hands, if for no other reason than self-preservation.  We need an organized trade apprenticeship program, and we need it now.”. When this happens, most people simply tighten the packing nut(s) to compress the packing material and stop or reduce the leak. Reduced chance for trapping air and running the box dry and cooking it. It is not uncommon to see stuffing boxes leak at a much higher rate. This usually occurs at the stuffing box or keyway cuts, the natural weak points. The standard adapter will fit most stuffing boxes in use in the United States, and custom adapters can be special ordered to fit other stuffing box designs. Packing material will harden over time (as the lubricant dries out) and gets worn away by shaft rotation, allowing water to pass and enter the vessel. The stuffing box is connected directly into the well production string, for example, by threading the lower end of a pack off assembly into a conventional flow tee or pipe fitting. These include periodic removal and inspection, as well as keeping the cooling hose mentioned above clear and open. Schraubenwelle Edelstahl Durchmesser 25 mm mit … Replacing clamps is straightforward and relatively easy.  Replacements should be made from all 316 alloy stainless steel, including the screw, and their bands should be solid rather than perforated (for more on hose clamp selection and use see Marine Systems Excellence Hose Clamps Part 1 and Part II).  For large diameter, heavy-walled hose,  conventional band clamps may have difficulty imparting the necessary compression to effect a watertight seal. In cases where maximum corrosion resistance is required—stuffing box and bilge pump hoses—then the higher price of 316 alloy clamps is easily justified. Frank Lanier is an accredited marine surveyor with over 30 years of experience in the marine industry. Simple stuffing box splash guard. bleeder; Eliminates one-threaded connection; Lower profile than classic models; Side outlets: 2-in. This corrosion can happen between wet or leaking decks to chain plates or in keel stubs to the stainless keel bolts but many are unaware that it can happen to prop shafts too. Periodically spraying the stuffing box with a corrosion inhibitor will reduce accumulation of this material and make service easier. Most stuffing boxes are designed to accept three rings of packing.  The joints should be oriented 120° apart from each other. Traditional waxed flax packing material is readily available in a variety of diameters.  With few exceptions, these are specifically matched to the shaft diameter, a two inch shaft, for instance, utilizes 3/8” packing while an inch and a half shaft utilizes ¼” packing.  Therefore, if you know your shaft diameter, obtaining the correct size packing is, with few exceptions, straightforward.  Some stuffing boxes used on Far Eastern-built vessels may deviate from this otherwise common protocol.  In those cases, and in the absence of reliable information from the vessel or stuffing box manufacturer, look for packing that slips into and completely fills the gap between the shaft and inside diameter of the stuffing box or packing nut. With additional plies, seen here, when compared to ordinary raw water hoses, proprietary stuffing box hose is especially rugged and twist resistant. Valve Stem Leakage Block valves are the most common valve in plants and often experience costly leakage. It will also have packing nut threads or a gland nut. Two wrenches must be used when tightening packing lock nuts,to ensure adequate tension is developed between the two nuts. Corrosive sealing water and environments can cause deterioration and subsequent leaks if the stuffing boxes aren’t corrosion-resistant. Simple stuffing box splash guard. 10 m/s and max. High speed vessel installations will usually have a water injection hose plumbed to the engines raw water cooling systems, which helps reduce heat generated between the two contact surfaces. The watch phrase when repacking a stuffing box, regardless of the material, is careful monitoring for the first few hours of operation.  Using an infra-red pyrometer, the stuffing box temperature should be monitored during this time, shooting the stuffing box and not the shaft (highly reflective surfaces such as shafts and hose clamps will often give erroneous readings); adjustments should be made if necessary.  No part of the stuffing box should exceed more than 30°F-40°F above ambient seawater temperature, regardless of drip rate, while at any speed.  In fact, with access to an infrared pyrometer, drip rates are much less important than they once were. 4. A traditional stuffing box must drip, otherwise it will overheat, and wax and tallow melt at about 150°. His website is bottom connection; 3-in. Packing has short life 12. Pump overheats, seizes, or both 18.

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