Valve maintenance is critical to any damage prevention program as it ensures the proper functioning of a pipeline. After all, if your valves do not turn freely and seal properly, you have little or no control of your crude oil or natural gas pipeline. The following are tips provided by Mr. Ron Meade. Ron is the Sales & Marketing Manager of DUALCO, the manufacturer of grease guns, valve lubricants, sealants and valve maintenance training. He is also an instructor, a troubleshooter and considered a valve maintenance expert.
Complying with these suggestions ensure safety, make the pipeline workers’ jobs easier and more efficient thus reducing pipeline operating expenses.
Tip #1 – Create a system map
Create a system map showing the location of all your valves. Number the valves on the map, and then create a manual showing size, type, location description and applicable notes. Some companies already have this requirement, but verify what you have and add any unlisted valves. In the event of an emergency – it may save a life.
Tip #2 – Have the right fittings on hand
Different valve styles often require different lubrication fittings. For example a plug valve may require a Lube Stick Injection Fitting or “tall” giant buttonhead fitting. These are sometimes referred to as “lube screws” and have either an NPSM thread down or a coarse bolt thread down. They have either a single or a double built-in internal check valve.
Most gate valves and ball valves normally use the shorter, stubbier lubrication fittings with an NPT thread down. Giant Buttonhead fittings with either single or double check valves are used. Vent cap fittings with or without Giant Buttonheads are also used.
A good maintenance practice is to have available spare fittings of each type in your tool box.
Tip #3 – Lubricating the plug of older plug valves
The primary seal in older lubricated plug valves is metal-to-metal between the plug and valve body. As pressure is applied to the valve through the lubrication fitting it builds up in the lube sealant reservoir under the plug, eventually “lifting” the plug and forcing it away from the metal-to-metal seal. At this point the lube sealant moves up and around the plug, lubricating it and forming an internal seal between the plug and the valve body.
Tip #4 – Vent Cap lubrication fittings
Vent Cap type lubrication fittings come in a variety of configurations and sizes. Cap sizes vary from ¾”–16 UNF and 7/8”–14 UNF to the more common 1”–14 UNS. These fittings have a pair of vent holes in the caps which must be checked and cleared before removing them. This allows trapped pressure (if any) to vent before the cap is removed. For a short time, Grove had a solid cap fitting with flats cut on the fitting threads, allowing pressure to escape. In all cases the fitting is also known by the NPT male thread down. The most common are ¼”, 3/8”, ½”, and the occasional larger sizes.
Tip #5 Common safety breach – substandard hoses
The most common hand-operated valve lubrication gun is the 10,000 psi hydraulic gun with a 15,000 psi cushioned gauge, 10,000 psi working pressure hose (12” or 18”), a 10,000 psi machined gauge tee and a Giant Buttonhead Coupler.
Be aware of manufacturers or vendors outfitting lubrication guns with inferior hoses or cast tees with working pressures of 6500 PSI. While this may appear to be a great way to save money it’s a safety breach and potentially dangerous. If you are shopping for a grease gun ask the manufacturer the pressure class of these components.
To help determine if your unit has the wrong pressure hose, the units in question may have a short (11 or 12 inch) solid black hose with little or no information on it, and the tee may have a casting outside the United States. If you’re not sure of the pressure rating on your hose call the manufacturer or 877-5DUALCO, as substandard hose assemblies are dangerous though they can be easily corrected.
Tip #6 – Valve cleaners
Valve cleaners are manufactured to safely clean valves without damaging the valve or the seals. There are three basic types of valve cleaners:
Type 1 - Hydrating Agent
A common valve cleaner is an amber-colored hydrating agent and often consists of a vegetable oil, usually castor oil. It penetrates and softens materials such as old, hardened lubricants and sealants within the valve. The cleaner should be left in the valve between four and twelve hours or more to work effectively. Alternately, a channel can be forced in as little as 30 minutes but this is a temporary fix. These softened materials along with loose sand, rust and other trash can then be pushed from the valve by pumping in a good grade of fresh lube sealant.
Type 2 – Heavy-Duty Cleaner
Often a heavy-duty valve cleaner is needed. This type of valve cleaner is often used by operating companies because it will clean rust deposits, cut old heavy waxes, remove varnish, sand, dust, rust, old hardened lubricants and sealants and thoroughly clean valves. This cleanser should be used for at least four hours or more to do a thorough job. It must then be purged from the valve with fresh lube sealant.
Type 3 – Dispersing Valve Cleaner
A revolutionary new product which cleans the interior of the valve thoroughly, works in about the same amount of time as the others, is replaced by fresh lube sealant, and then disperses when it is pushed into the product stream is the dispersing valve cleaner. Dispersing valve cleaner as it is known has the advantage of not fouling such items as meters, orifice plates and so forth. If any of this material does reach them it can be cleaned with water instead of solvent.
Tip #7
To do their job properly, valve lubricants must function as valve sealants, and sealants must also function as lubricants. Because of their dual purposes we commonly refer to them as lube sealants. To determine the best lube sealant for your application you should consider the following:
- What temperature range (high and low) will the material be subjected to?
- What pressures will we be dealing with?
- Is there any CO2 or H2S present? If so, in what concentrations?
- Is there water present? If so, how much?
- Are there any other contaminants which should cause concern?
- Are there injected chemicals which control paraffin or other unwanted materials present?
- Are there any problems that we are unaware of?
- Do I want a lube sealant with a vegetable oil or a synthetic oil base?
Many castor oil based products have the advantages of synthetic oils; however they are less stable and subject to chemical reactions. Additionally, synthetic oil base has superior stability, longevity and is less expensive than vegetable oil based sealants. For these reasons we recommend using synthetic oil based lubricants.
"SAE AMS-G-6032 “Grease, Plug Valve, Gasoline and Oil Resistant” provides an excellent guide to valve lube sealant.
These tips are provided courtesy of DUALCO - the manufacturer of grease guns, valve lubricants, sealants and valve maintenance training.
Tags: natural gas pipeline, valve maintenance, damage prevention
If you have a DUALCO hydraulic grease gun (models: 11035 and 11000R) that is in need of repair or service, rather than spending nearly $700 on new equipment consider having your existing grease gun refurbished or exchanged for a fraction of the cost. If your equipment is not corroded or abused and all its components are fully assembled, it is a prime candidate for this program.
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