Tagged With "Leaks"

Topic

Piping Condition Management

Bob Pavkovic ·
I am doing a piping survey in our plant. Inspections to take place to determine which piping needs the most attention. Most of our service is baywater or process water from Steel Operations. Steam piping will need inspection as well....
Topic

Steam Turbine Leak

rgf12 ·
I have a steam leak I've been monitoring that is located on the horizontal joint of the HP section of a GE steam turbine. The steam conditions are 1800 PSIG/1040F and the leak has been measured between 65 and 72dB. Is there a way to calculate the steam leak percentage increase if the sound level increases to 82dB? 95dB? I don't know how big the area is that is leaking as it is still insulated so I can't assume a size and do an orifice calc. Management wants an action point.
Topic

Underground Leaks

Chuck Scott ·
Currently have a customer that is experiencing a firewater leak to the magnitude of 14K gallons of water a day. All the piping has been checked except about 300 feet which is 8 feet underground.   Is there anyone with experience in using an...
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Solutions 2.0 Virtual Conference

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Re: Underground Leaks

Allan Rienstra ·
Hi Charles, I suppose that leak will be most easily located when the sinkhole appears? LOL Seriously, though, finding that leak with ultrasound will not be impossible, but not easy either. 1. Know or get access to drawings that show where the piping runs 2. Drive a length of metal rebar into the ground above the pipe. If it is buried 8' then obviously don't drive it 9' into the ground. 3. Attach an SDT RS1 Threaded Sensor with Magnetic Mount on the top of the rebar. 4. Set the amplification...
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Re: Underground Leaks

Chuck Scott ·
Hi Allen, What Frequency range on the SDT270 would you suspect to be most applicable to this inspection. We will definitely document this inspection and share. You know me....always pushing the limits and finding new uses for Ultrasound. How far down into the ground do I need to drive the rebar to get acceptable readings. Running rebar deep into the ground and pulling it back out 60 times is not going to be easy for sure.
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Re: Underground Leaks

Allan Rienstra ·
I would leave the SDT270 set to its natural resonant frequency of 38.4kHz. The RS1 sensor is optimized at this frequency and tuning away from it only serves to make the sensor deaf. I can check to see if one of our underground storage tank sensors, which operates at a lower frequency, is a good option and get back to you. To make the rebar easier to insert and remove weld a T to the top of it so you can twist and pull. I would think that 2-3' will be sufficient but I should think that...
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Re: Underground Leaks

Walt Strong ·
Chuck, If you already have the SDT270, then give it a try. You might consider using a smooth steel rod instead of rebar, since it would be easier to drive and remove from the ground. If you have a 2-channel vibration analyzer and above ground access to each end of the pipe, then try cross-correlation measurement to locate the leak distance from one end or the other. There is information on internet about this technique and several leak detection systems are based on it. Whether you try...
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Re: Underground Leaks

Jim S ·
If your going to drive steel rods into the ground ask your electrical maintenance department if they have a Hilti hammer drill with a ground rod driver attachment, They come in nominal ground rod sizes. It will run the rod into the ground like butter instead of pounding them in with a hammer.Smarter not harder.Also if you are leaking that much liquid you may want to try using an infrared imager from an elevated level. This may be to deep to see but worth a try.The thermal capacitance of the...
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Re: Underground Leaks

Jim ·
Ok let’s go through this a little before you spend a HECK of a lot of time finding this leak. I typically find this type of leak on a fire main in 1.5 hours or less. First of all, yes, I teach ultrasound and I am an SDT user but for this application you are wasting your time. First of all DO NOT USE 38.4 kHz "TOO" high. Utilize the 5hz-18khz range. Some SDT units have frequency adjusts…use 15.1 kHz if you use the SDT instrument. Other instruments that do not adjust that low, use 20kHz. You...
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Re: Piping Condition Management

Rao Shahbaz ·
LRUT( Long range Ultrasonic testing) can help in this case to my knowledge. Further an NDT expert can tell you. To my best info, its scanning ranges upto +/-40 meter from the probe wrapped up at even buried pipeline. Just only you have to dig there where you have to install probe.
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Re: Piping Condition Management

Dave Reynolds ·
As stated NDT technology like UT, here is an article that explains the theory of this type of testing. http://www.olympus-ims.com/en/...on-thickness-gaging/ With insulated pipes you will need to install rubber plugs for thickness measurement locations or TML's http://www.inspectionplugstrategies.com/ PSM process safety managed chemicals require MIP mechincal intergrity programs which include visual and UT measurements @ 5 and 10 yr intervals as part of a MIP program. If you are already using...
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Re: Steam Turbine Leak

rgf12 ·
Update: Vendor sealed both leak locations at full power prior to a scheduled shutdown. At unit restart both the east and west side joints were found to have minor leakage. Will continue to monitor and reseal as conditions dictate. Fall outage inspection and repairs are in the planning stage.
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Re: Steam Turbine Leak

Allan Rienstra ·
Hello RGF12. Some questions: Are you measuring the leak the same way each time? From the same distance and angle? Is the leak behind insulated material or open to the air? Are you using SDT or UE ultrasound instrument to measure/detect the leak? I am concerned that the leak was measured between 65 and 72dBμV. As this is a difference of 7dBμV, which equates to a difference of more than 2x the signal; well that seems very inconsistent for a steam leak which should be much steadier. The second...
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Re: Steam Turbine Leak

rgf12 ·
Thanks for the reply. The leak is under the insulation but I've opened a slot so I can take the readings. I'm using an UE10K with the airborne module using the cone. Frequency is set at 40KHz. I have about 8 data points that vary between 65 and 72 with the 72 reading the latest with an "average" reading of 68 . I try to be consistent in the placement of the probe but there is always a human factor. My management wants an action point and just based on previous experience I pulled 85dB out of...
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Re: Steam Turbine Leak

Allan Rienstra ·
You're of course most welcome. I hope I can help you here. And please, since I failed to mention it in the first response, you are working with high temp, high pressure steam. Please exercise caution and follow all organizational safety procedures. Steam can kill. What distance are you standing from the leak? More specifically what is the distance between the leak source and your sensor? By "cone" do you mean UE's Long Range Module? I am concerned by the lack of consistency in your readings.
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Re: Steam Turbine Leak

rgf12 ·
I will get you a pic of the location of the steam leak. I'm using the UE air module with the rubber focusing cover and I position the probe above the leak and try to duplicate the angle and the insertion length behind the insulation blanket so I believe I'm pretty consistent in the positioning. We had a similar leak on the opposite side of the HP a couple months ago and the level increased about 12db before we shutdown and sealed it. Unfortunately I was brought in late in the monitoring...
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Re: Steam Turbine Leak

rgf12 ·
Update: We took an auto shutdown on the subject unit due to unrelated issues that will require the turbine to be on the gear until it' cold so we can make some repairs. It will be interesting what the shutdown and the restart will have on the HP joint leak. I've attached a picture of the leak location. The data is collected from the space in the top of the small insulation blanket shown in the pic. As far as safety we cautioned taped the entrance door to insure we don't have any tourists...
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Re: Steam Turbine Leak

rgf12 ·
Update: Returned the unit to full power operation and the sound level increased to 96dB. We are going to get a vendor in to shoot the joint with sealant. Fortunately there is valves installed near this joint to do that. I'm reluctant to continue monitoring this beast as the steam leakage and resultant temperature makes it a little dicey to be in the close quarters of the leak even when sporting the proper PPE.
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Re: Steam Turbine Leak

Walt Strong ·
"The same thing that happens when you take your thumb off the end of a garden hose. The turbulence goes away because the flow is now less restricted. I am not suggesting this will happen in your case, I am merely preparing you for the possibility that the leak may get quieter and you will need to explain that too." I don't think this analogy is relevant, since steam is compressible and water is not. Once steam passing through an orifice reaches sonic velocity the flow rate is constant. As...
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Re: Underground Leaks

JE957 ·
Thanks for the information. I have been curious about testing our underground firewater lines at the plant I'm based at with our ultrasonic equipment. We have had some failures this year and there have been questions about using ultrasonic equipment to test for leaks. It sounds like third party may be the way to go.
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Re: Underground Leaks

jvoitl ·
Did u find your leak and if you did how?
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Re: Helium Leak Detection

Jim ·
Depends on the pressure, type of leak (tear, crack, piping, distance) at the leak site. Typically, ultrasound is rated at finding a leak at 1x10-3 to 1x10-4 std/cc/sec.(ASNT E-1002-96). Of course helium & specific gas detectors and mass spectrometers such as those typically used for helium as well detectors that read difference in thermoconductivity, are more sensitive than the UT. At one time, UE Systems sold a liquid known as LLA or Liquid Leak Amplifier. This was a low surface tension...
Topic

Helium Leak Detection

Chuck Scott ·
Anyone have experience using Ultrasound for Helium Leak detection. One of my guys just completed the level 1 with SDT and the instructor was saying it difficult to detect. Any thoughts would be appreciated.
Topic

LEAK OIL AT BEARING HOUSING MOTOR

Sin ·
Hi everybody, The motor 1400 kW leak oil at bearing housing (see below photo). What is this issue? If over grease, how to remove spent grease? How to troubleshooting? Thank you.
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Re: LEAK OIL AT BEARING HOUSING MOTOR

Shurafa ·
Maybe if you give more information the forum members could help. General recommendations: Clean the bearing housing very thoroughly (no residual signs of the oil or grease). Then regularly check the potential locations of leakage, while the motor is running. This step will help you to identify the source point of the leakage. Is this a serious problem? Regards- Ali M. Al-Shurafa
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