HOSES play a key role in many areas of the bulk transport industry, including product delivery and tank cleaning.
Unfortunately, they do not enjoy the same reputation as the tanks.
"The whistle is like the ... red-haired son of the industry," said Kip Hart, president of Hart Industries. "Nobody really wants to treat them, so the only people who pay attention to them are those who have to deal with the consequences of mistakes or those who pay the bills."
"Everyone does not want to deal with them, and that's why they often do not."
And of course, the fact that you do not touch the pipes causes problems, far away from the eyes, far from the heart, which does not mean that you come out of the wood. Hart has seen them all during his career with the rubber supplier. based in Middletown, Ohio. In addition to opening four offices before succeeding his father as president, he examined hundreds of flexible failures, worked with testing laboratories to determine the causes, and helped build a complete database of all anomalies.
Hart outlined some of these causes, as well as best practices regarding hose safety and external and internal signs of imminent hose failure in "Cleaning Hose Problems", presentation of the Sub-Committee on Tank Wash Safety in the NTTC Security Council 2019. Meetings.
"We will talk about some of the avoidable hose failures we see and how we think it could be done to fix them," Hart said. "There are many cases where a hose failure can be prevented, but ... most can be prevented."
seal
As a pipe distributor, Hart Industries certifies all of its loose pipes, fittings and fittings at specific pressures and then sends them for multiple uses, Hart said. The company uses the acronym SEALED to specify the parameters used to define the pipeline it provides to the industry.
Size: The inside diameter multiplied by the total length of the set.
Temperature: maximum and minimum tube temperatures during routine cycles or cleaning processes.
Application: The way the pipeline is physically used, including maximum temperature and cycle time.
Media (dry, liquid or gaseous): The condition of the product in the pipe, with chemical compatibility checked against the liquid resistance data provided by the pipe manufacturer.
Pressure: The maximum pressure or vacuum that a pipe sees in one of its cycles.
Tips: Choose the correct mounting method and method of attachment and always check the strength of the valve and gasket.
Delivery: Make sure that the delivery terms are clearly communicated.
The acronym and steps to certify each pipe in accordance with the standard are an essential element of Hart Industries' efforts to prevent pipe failures.
"Everyone is exposed to the effects of hose failure, including the person working with the hoses in the tank cleaning environment, the drivers using the hoses to deliver the product, the receptionist and the general public, depending on the circumstances. All the consequences of failure, "said Hart.
According to Hart, after the pipeline leaves their company, the best-equipped people, including drivers, technicians, operators and tank cleaners, identify the pipes that could fail. ,
Tank cleaners are in a unique position to identify impending or causing faults.
Hart explained that most of the avoidable mistakes he sees occur during tank washing.
"The technicians and drivers are the two front men," he said. "If a company has to undergo flexible flexibility training for the safety of flexible hoses, these two roles need to be highlighted."
Best Practices
Hart recommended that two proven methods lead to a significant reduction in the number of avoidable pipe defects:
1. The last person touching the pipe before putting it back into service should clean it so as not to affect the integrity of the pipe, and make a final inspection of the appearance and lining.
2. Anyone using the hose for the first time after cleaning should perform the function indicated on most hazardous material hoses: "Inspect the hose before each use, using a damaged hose can be dangerous.
Training these best practices in key positions requires training and repetition, but the reward potential is considerable.
"If that happened, we'd probably have between 70% and 80% fewer hose failures," Hart said.
Washing tanks is the most common cause of hose failure, and according to Hart, there are as many as eight out of ten mistakes caused by a high-pressure cleaning rod. , When water passes from a push rod into the inner lining of the pipe, the pipe casing is exposed to the transported liquid, which almost always results in breakage, often without any apparent external defects.
"The inner lining of a pipe, especially in the chemical field, is basically a very thin and delicate piece of plastic," said Hart. "It can be a cross-linked polyethylene material or a modified cross-linked polyethylene material, and these two are probably the thickest (materials)."
Hart Industries' best-selling hose is modified cross-linked polyethylene, which has a thicker, more flexible and vulcanized inner tube, so it is not as susceptible to thermal deformation, Hart said.
The industry's second most popular pipe, used by many other tube manufacturers, is ultra-high molecular weight polyethylene (UHMW), which is believed to be more susceptible to thermal deformation and more easily damaged by sticks detergents that deliver up to 3,000 psi. , often at high temperatures.
Anything over 180 degrees F can damage the pipe, Hart said.
"The combination of heat and pressure is like a knife and it will go through a tube," he said.
Regardless of the tube in the tube, the hardness decreases as the thermometer rises, even if it is a vulcanized rubber. Then it begins to soften and weaken the hose with increasing temperature, and when the temperature is high and hits it. With a high-pressure water jet, it is very easy to damage it. "
inspections
External visual inspection of pipes shall include:
• Make sure the appropriate label and / or ribbon is installed on the pipe
• Look for cuts, notches, or worn areas on the pipe cover that expose the fabric or wire reinforcement.
• Look for soft spots that may indicate sweating, blisters, blisters, bumps, or loose spots on the deck, as well as squeezes or bent sections, which probably means the hose is not good.
• Dispose of or repair pipes with scratches or grooves that expose the backing or cable
• Dispose of or repair bent or crushed tubing with more than 20% of its original roundness
• Make sure that the fittings do not slip, which is usually indicated by an unusual distance between the end of the hose and the fitting (the end of the hose must be against the fitting).
Hart Industries strongly supports the regular pressure test, Hart said.
"(And) if you want to do that, you need to put an identifier on (the pipe) so that you do not try out the same pipe too many times and prove that the pipe has been tested over a period of time." he said.
Hart also stated that it was important to inspect the pipe cover, but that any imperfection was not necessarily a sign of impending failure.
"If it has a cut in a pipe and does not expose the textile thread or reinforcement, it's kind of like a notch in a tire," he said. "That does not really mean the hose should be taken out of service, but if it has reinforcing cables, it should be repaired or thrown away."
Internal visual inspection of pipes shall include:
• Look inside the tube with a flashlight and look into the hole
• Examine the inside of the tube for bubbles, soft or gummy spots, tube cracks, excessively worn tubes, or swelling of the tube if the tube's inside diameter is smaller than the original inside diameter. from manufacturer
• Look for scars on the chuck that could be caused by the use of a high pressure cleaning pipe or rotating brush
Although pushrods are the main cause of interior trim damage, steam lances are also dangerous to pipes.
Videoscopes are useful for internal inspections, but not compulsory. Most internal signs of impending hose failure, up to 90%, are visible in the first two feet of the hose, Hart says.
A clutch inspection (final adjustment) must contain:
• Inspect clutches for worn parts that prevent normal operation.
• Check for any damage to the safety locks that may interfere with proper operation.
• Check that the connections are not worn. Pliers or loose bands; Worn or broken handles, cam arms and pins
• Couplings must be checked for wear and concentricity. With a new accessory as standard, check each hose end to make sure the couplings fit properly.
• Carefully inspect the gaskets and gasket seating areas for signs of wear.
"Any detail missed in a critical pipe assembly can bite you again," Hart said.
Check the cam clutches for broken or missing arms, cracks or dents in the accessory housing, and worn or cracked seals. Check the automatic locking for all these problems and additionally check the locking mechanism for malfunctions (the locking cam arms must "click" when creating a positive lock).
"There are no camera ears, broken camera ears, they are cheap, so the risk is not worth it," said Hart.
Wash things that you do or do not want to do
Wash liquid washers connecting the cleaning solution tube to the hood or cone of the centrifuge have their own problems, Hart said.
"We do a lot of business with a lot of tank cleaning and centrifugal hose was a universal problem from the start," he complained. "There has never been a perfect hose, and those approaching cost around $ 1,500 each and nobody wants to buy them."
According to Hart, tank cleaning is one of the most dangerous areas in oil tanker shipping. Flexible hoses are often bent with twisted ends because of their height and height differences in hoists. Chain, are probably the most dangerous uses in washing, which is why proper handling is crucial.
"These hoses should receive special attention, probably more than a flexible supply, and teach the operator to investigate and identify potential problems before they occur (it's important)," Hart said.
Articulated joints are an effective solution for eliminating deformations.
"We recommend using mechanical locking accessories in tool kits," Hart said. "Now we produce almost 100% of our disc hoses with permanently attached accessories."
Do not do pipe cleaning:
• Do not soak the pipes for more than 20 minutes.
• The tank temperature should not exceed 180 ° F
• Never use push rods or steam lances to clean the inside of the hoses.
Do not wash the steam pipe of the tank:
• Never use raven foot accessories for steam
• Never use cam lock accessories for steam
"Cam and neck fittings, such as used in tankers or rotary hoses, and levers are not designed for steam," said Hart.
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