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    Gate valve or Ball Valve? (37 Posts)

  • Art Pittaway Art Pittaway @ 10:24 AM
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    Gate valves have a place

    in steam systems simply because they are full port. It isn't always possible or practical to drip before an isolation valve. A globe valve in a horizontal steam line will present a "dam" and back up condensate, and cause hammer. Large ball valves have there own problems, you think Gates get stuck! Perhaps the question of installation with stem up, horizontal or down should be asked. Stem up and all the c**p in the pipe lodges in the lower channel. Stem horizontal and the side channel is full. Down and the blade has a clean seating area? Any thoughts?
  • Bob Bob @ 11:40 AM
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    Yes

    your absouluty right, on the steam side stop valves are required to be either gate or non-reversing valves at the boiler connection. Gates offer no resistance ( or very little ) when fully open, a non-reversing valve looks more like a globe valve internaly but when fully open offers little resistance to flow. This set-up will depend on other factors such as 2 boilers in battery on a common header with boiler manholes. Free blowing drains between these valves are gate valves. I have not to this day seen any ball valves used in this capacity. Gate valves do definitly have a place.
  • Tony Conner Tony Conner @ 2:56 PM
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    We'll....

    ...have to agree to disagree, I guess. I really don't see slow opening/closing as a throttling service. The places I most often see ball valves used (abused?) for throttling is ahead of steam control valves in industrial plants. Most temp and pressure control valves are grossly oversized, and hunt themselves to death in short order. To get around this, the "quick fix" is to throttle the upstream isolation valve. This causes a pressure drop across the throttled valve, which means the control valve sees a reduced inlet pressure. Since the downstream pressure remains the same, the lower inlet pressure means a smaller delta-P, so the valve has it's capacity reduced accordingly. The throttling of a ball or gate valve in this situation makes the control valve "smaller". And it does work. However, after a few weeks of this kind of service, the upstream isolation valve rarely holds when closed.
  • Art Pittaway Art Pittaway @ 9:27 AM
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    Tony,Thanks for the reminder....

    of a water temp. control problem I was called on at a Caterpillar plant. 100psi steam through a 4" Powers double seated modulating valve. Been there for years, never worked right from day one. I looked at the HX spec. and figured that the 2% average leakage from the valve was enough to feed the HX at full load. The actuator never moved, it never had to. Valve sizing, when it comes to sales....there never big enough. ;-)
  • Bob Bob @ 3:50 AM
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    Tony

    I'll agree with that. On steam lines above 3/4 I have never seen or would I probably feel comfortable using ball valves to control steam flow, even as a temporary means, globe valves have always been the tradition. Even though these valves are rated for steam service it just isn't common place to install them at these points. If a PRV was taken out of service on the deareator a globe valve on the by-pass line was used to control steam flow until repairs are made. But for water service they are becoming popular on change-outs. My comment on the water column situation was through personnal experience. If the valve was opened to quiclky for blowdown the gauge glass would shoot up with water. This always gave me the impression that any scum or sludge was not being removed, but shot back up the the glass. Eventually the blowdown would stabalize but at increased waste. By opening slowly this gave the column a chance to equalize and give a better cleaning. Ball valves were used here with no problems. On high pressure boilers as you know the blowdown is violent causing a cheap valve to fail quickly.
  • Mad Dog Mad Dog @ 10:35 AM
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    I'm with Dopey!!!!!! Just kidding Mr Myron......................

    I am old school as well. A properly exercised gate valve will last many. many decades. I've seen a lot of first generation ball valves - yes - even my beloved Apollo's - inoperable after 20 years. I have used ball valves on steam when I had no choice, but I feel a nice gate valve holds up much better to the excessive heat and temp of steam. Mad Dog To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
  • Tony Conner Tony Conner @ 9:12 AM
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    Valves & Piping...

    ... used for blow down are indeed in a severe service - probably the most severe in the entire steam plant. Any pipe, fitting or valve used must meet ASME B31.1 Power Piping Code requirements. But I still maintain that since water column and bottom blow down valves are closed tight more than 99% of the time, they don't really qualify as being in "throttling" service. They're only open for a few seconds each shift. Not more than a minute total in a 24 hour period.
  • Bryan Bryan @ 7:54 AM
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    I will check this stuff out. The burner has been replaced sometime in the last 10 years. The boiler plate cant be read. Only thing you can get off the plate is the name which is National US Radiator, which was bought out in the 50's. I dont recall the exact EDR but I think it was around 700 I will have to double check that. I will check the burner out tonight. Thanks again for all your help. As far as the valves go sounds like you can flip a coin:) Bryan
  • Robert O'Connor Robert O'Connor @ 5:58 PM
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    700 edr is

    about 168,000 btu net. So add 20% for burner inefficiecy. About 201,000 btu input So some where between1.25 and 1.5 gallons oil per hr. Of coure a pro should look it all over with a careful eye. Regards, Robert
  • N/A @ 12:36 PM

    Ball Valves verses Gate valves

    that is the question? Ball valves for screw pipe are manufactired up to 3" the same as gate valves. I personally like gate valves, I am from the old school... There is nothing wrong with using a ball valve on any piping and in most instances the ball valve costs less money. I am speaking of using rated valves only, made in America stuff. In your application you do not need a full port ball valve. The valve placement is kinda like having a control valve on a fixture. That valve is placed between the boiler and the automatic feed valve. The feed valve supplies less water to the boiler than you use when you wash your hands, face or brush your teeth. A full ported valve is not needed. You would use the full port valve if you were changing the the valve on your water main. Oh incidentally the valve after thr feed valve looks like a globe valve. Jake
  • Bryan Bryan @ 9:36 AM
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    Gate valve or Ball Valve?

    I need to replace that cobbed in piece of Galvanized on the return. You can see the rust spot towords the top and it is about paper thin. I am also going to replace the fittings below. As per the advice I received on the wall I want to redo the water lines and get it off of the softend water. And run some copper. That boiler has been running for a good 50 years like that until we had the softner put in. So I guess what my question is. Can I put ball valves on those water lines? I have seen it both ways on the pics of the installs you guys post. Thanks, Bryan
  • Bob Bob @ 12:16 PM
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    Valves

    Yes, you can go with " the properly rated ball valves" in place of gate and globe valves. Gate valves are not meant to be used as a throttling valve, they are full port, positive closing, and the gate will wear if used for throttling action. Globe and ball valves are suited for throttling action. Throttling action would be used on the by-pass feed line if needed, if you were to need to perform service on the feed valve you could isolate it with a gate or ball, then use a globe or ball to feed the boiler until repairs are completed. Use full port ball valves, stainless steel ball.
  • Bryan Bryan @ 4:50 PM
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    Thanks Robert
  • Bob Bob @ 10:11 PM
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    All Good Points

    but also throttling does not have to soley mean opening to full, then closing to full. Throttling can work within a designed range to maintain a set pressure. At a pressure reducing station the valve will throttle to maintain set pressure, if the hi side pressure drops off the valve will have to throttle open to maintain lo side. The valve can open fully slowly and/or close off slowly behaving in a variable throttling manner. On the other hand a balancing valve will be set to a desired pressure/flow and held there till manually changed staying in a stationary throttling state. Any valve can throttle, but some are not recommended for this use. By opening a blowdown valve slowly you are effectivly throttling and the valve has to be able to stand up to wear, a gate valve will wear prematurly quickly and eventually not give positive shut-off. This analogy follows the throttle on your car, it can either open quickly to full, or open and close slowly to give a more precise metering effect. but in any case the valve still behaves in a throttling manner and has to be able to stand up to wear caused by it. If you notice by-pass lines will have a globe valve for throttling and the feed will have gate valves in all older work. Newer runs can run solely on ball valves, if the correct valves are chosen for the type off service involved. That was the initial post question/answer. On chemical control metering blocks will need to be used if you want precise control, these can work in conjuction with full open/full close, or throttling (modulating) ball valve units. I'm not trying to sound picky, I completetly understand what you are saying. I've seen ball valves wear in situations where you would think they would not, these were cheap units just waiting to fail.
  • Bryan Bryan @ 9:53 AM
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    I am not sure if I should start a new thread or not so I will try in this one. I pulled that return apart and found it to be in very rough shape. From about halfway down the galvanized pipe it was full of crud. Below that it was even worse. Some of it was pluged shut. The nipple between the elbow and tee had the threads disinigrate and is very brittle. When the boiler got to the end of draining it was pretty black and a lot of crud. What I am wondering is this the best way to have this piped? Thanks Bryan
  • Steamhead Steamhead @ 5:21 PM
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    Bryan, that's fairly typical

    of steel pipe on wet returns. Yours was a lot worse due to the venting situation we just fixed. As long as the pipe carries NO steam, copper would be a good replacement. That piece looks like it's mostly below the waterline so copper should be OK, maybe use a short black nipple on the very top to get down below the waterline. I know copper is controversial, but I've never had a problem with it- at least not in the Baltimore area where we have really good water. If there's a way to do it, run a hose into the top of the boiler before fixing the pipes and flush out all the gunk. One way to do this is to remove the safety valve and stick the hose into the opening. To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
    "Reducing our country's energy consumption, one system at a time"

    Steam, Vapor & Hot-Water Heating Specialists

    Oil & Gas Burner Service

    Baltimore, MD (USA) and consulting anywhere.
  • Bryan Bryan @ 12:05 PM
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    Steamhead, Thanks I am going to stick with the steel. I will make sure to flush the crud out. Cant wait to fire this baby up this year. This will be the first year of the new and improved steam system. What are your thoughts on down firing the boiler? It was downfired last year before the venting. I dont know what size nozzel he put in. Is there a way to figure out the proper size nozzel? I plan to have the boiler serviced soon so I would like to take care of that then. Many thanks, Bryan
  • Robert O'Connor Robert O'Connor @ 5:17 PM
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    Nozzle

    My 2 cents: Nozzle should be sized according to rating plate of boier- assuming it is a modern boiler. I don't reccomend varying to much from this spec. I have seen other problems develop. If it is and older coal version try to get a net stack temp in the 450 -550 range, a bit more if you have an outside chimney. Regards Robert
  • Steamhead Steamhead @ 6:34 PM
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    There are several opinions on down-firing

    but the common thread that runs thru them all is you don't want to get the stack temp so low that the flue gases will condense. This means they shouldn't go below about 300 degrees or so in the stack. If a boiler is grossly oversized, down-firing can cure short-cycling. Of course, the best solution here is a new, properly sized boiler, but sometimes that has to wait a while. And if a flame-retention burner is installed in a boiler that didn't already have one, the nozzle size should be reduced (by roughly 20%) to match the BTU output of the original burner's less-efficient flame. I've seen a few of these that weren't reduced, and the results weren't pretty. So, my short answer to your question is "it depends". How much radiation do you have (get Dan's book "E.D.R." if you don't know) and what is the rating of your boiler? What size nozzle is in that burner now? And is it a flame-retention burner? To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
    "Reducing our country's energy consumption, one system at a time"

    Steam, Vapor & Hot-Water Heating Specialists

    Oil & Gas Burner Service

    Baltimore, MD (USA) and consulting anywhere.
  • Bob Bob @ 7:53 PM
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    TurnDown Possibilities

    I would find out from the boiler/burner manufactuer regarding turndown ratios, If for some reason the burner was changed out and is not a specified model for that particular boiler. Most boilers have a range to work with-in, especially if it's a oversized capacity situation. In my opinion, and I believe your decision is right by going with black iron, avoid galvanized. Copper is acceptable for condensate contact, but again I would avoid this if you can. Have you made a decision on which type valves you are going with, LOL
  • Arthur Arthur @ 6:40 AM
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    Ball, Gate or goble Valves

    Gate valves must be one of the worse valve ever made, The number of times I've been on old systems were the lime has got to the valve and one has to turn the valve off really hard to get it to seal for maintenance and then when you go to turn on again the rotten thing drops it's gate and won't open. For just plain isolation give me a ball every time, For regulating/isolating go for a special reg/isol valve which is a kind of globe valve. For steam or agressive water use S/S seating. Otherwise use brass seat with telfon washer. I've got a gate valve at the moment to fix in the next few days valve won't open & sheared the spindle, 3 hrs to drain down replace and refill. For high pressure steam a really good quailty s/s valve is needed and be careful not to let it wiredrawing which will cut the valve and/or seat out in no time. Quality valves pays for them selves in the long run (like most things LOL)
  • hot rod hot rod @ 5:49 PM
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    Oh, they fail alright

    but the issue is more about the adjustability. My neighbor has a pump and dump heat pump system. On the outlet side of the dump loop is a 1" ball valve that adjust the "dump" flow. In 8 years he has replaced 3 ball valves as the partially closed ball erodes, then the flow changes, and finally the heat pump trips out. His heat pump is his sole source of heat and cooling, and runs year 'round. I tried to sell him a valve designed exactly for that purpose, but he is comfortable with a $9 ball valve replacement every few years, WHATEVER! Although he hates the inconvience of the HP triping off! Again, it depends on how "right" you want to apply the valve to the application :) hot rod
  • Bob Bob @ 10:23 PM
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    Yep

    > but the issue is more about the adjustability.
    > My neighbor has a pump and dump heat pump system.
    > On the outlet side of the dump loop is a 1" ball
    > valve that adjust the "dump" flow. In 8 years he
    > has replaced 3 ball valves as the partially
    > closed ball erodes, then the flow changes, and
    > finally the heat pump trips out. His heat pump is
    > his sole source of heat and cooling, and runs
    > year 'round.
    >
    > I tried to sell him a valve
    > designed exactly for that purpose, but he is
    > comfortable with a $9 ball valve replacement
    > every few years, WHATEVER! Although he hates the
    > inconvience of the HP triping off!
    >
    > Again, it
    > depends on how "right" you want to apply the
    > valve to the application :)
    >
    > hot rod

  • Bob Bob @ 10:28 PM
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    Yep

    I'm surprised that $9 valve lasted 2 yrs. I don't believe or did I say to use these valves for metering on a full time basis. There are valves designed for that. The initial post was for valve replacement on a res boiler, a throttling ball valve for the bypass line, which is not used often, will suit this just fine. Watts sells a line of ball valves designed with throttling capabilities. Any valve will wear. They all have pros and cons.
  • Jamie Hall Jamie Hall @ 9:01 PM
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    ball valves, gate valves, globe valves...

    What a topic! They are all good for something, all of them! Gates are, or should be, either open or closed -- there can be tremendous wear on the guides at part openings. That said, I've use them for throttling, but never less than half open. Gate valves are great for flow control, but you do have to watch the pressure drop through them, and they really shouldn't be on low-pressure steam mains (too much pressure drop and some VERY interesting balance/no heat problems). Ball valves are pretty good, all around. Reduced port is fine -- except, again, on low pressure steam mains (same pressure drop problem) (don't ask: been there, done that, got the T-shirt).
    Jamie

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Mark J Strawcutter Mark J Strawcutter @ 10:25 PM
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    What is the difference between

    throttling and flow control? Mark
  • Jamie Hall Jamie Hall @ 10:39 PM
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    argh

    not much, unless you get really picky... bad choice of words! However, if you insist... in throttling, the objective is either to set a specific pressure drop or to drop to a specific pressure; in flow control, the objective is to set a particular flow rate, regardless of pressure. Hydronic stuff often is working with flow control... However... I wasn't being picky, just sloppy! Sorry...
    Jamie

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • pfitter pfitter @ 8:17 AM
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    ball valves

    you guys ever seen or used a B&G cirrcut setter balance valve? up through at least 4" they are ball valves, after that they more globe like, i dont believe they are an exact globe as we think of it though.The taco balance valves are also ball valves. I prefer the B&G over the tacos but I prefer the TA (victaulic) true globe style over each. the B&G are what all engineers around here spec, but they allow Tacos as a substatute. p
  • Bryan Bryan @ 1:27 PM
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    Thanks for the responses I wasnt sure if it made much difference or not. I want nothing but the best for my baby. She needs to be loved and nurtured. With heating season comming up I want to make sure everything is perfect for this system. After putting on a fist full of Gortons this spring(thanks Steamhead) I cant wait for the temp to drop. Thanks again Bryan
  • Scott Scott @ 3:48 PM
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    Throttling

    Should allways be done with a globe valve. Ball valves ar'nt made for that. That being said I see no reason why a ball valve can't be used on the water lines here. If you have a situation that calls for throttling then a globe valve - everytime. Scott To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
  • Bob Bob @ 4:51 PM
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    Valves

    There is some truth to that, a cheap manual ball valve will not handle throttling very well, wear is excessive. The same is true for cheap globe valves, and direction of flow through a globe valve is critical, flow has to be in from the lower section, with a ball valve this is not an issue. How many homeowners pay attention to flow patterns through globe valves? But being a full time stationary engineer and having extensive experience with valves on medium and high pressure boilers a good quality full port, stainless steel ball valve will stand up to throttling wear just as well as a good quality globe valve. We use them on water columns where blowdown is frequent, and violent, throttling is essential coupled with quick opening and closing if needed. Chemical treatment system uses nothing but ball valves where at times throttling is needed during metering valve cleaning/service. Using full port valves reduces uneven wear on the ball edges due to reduced turbulance, they also allow quicker fill times on by-pass lines due to lower pressure drops. A ball valve that is not full port is essentially throttling all the time causing ball edge wear with seat degradation. Automatic ball valve units are used mainly for TDS control, the cost of these valves are prohibitive to the normal home owner's system. The failure rate on these valves are minimal, and rebuild is just as easy, you can't rebuild a failed/fouled seat on a gate, on a globe you could try and clean them but they won't last long. So in closing, Ball valves can and are used for throttling. I always believed that you got what you paid for, pay cheap, get cheap.
  • hot rod hot rod @ 9:16 AM
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    The issue with ball valves for throttling

    for precise work, like injection mixing, or temperature balance, is the fact they are not equal proportion valves. In other words A "true" balance valve has a tapered seat and disc, and usually a fine threaded stem. This makes fine tuning very easy. A ball valve has most of it "balance ability" in the final movement of the handle. Hard to be accurate. Sometime exactness is not needed. The sharp edge a partially closed ball valve presents when partially closed, can be a "wear point." Depends on what you are flowing through it, and the velocity, I suppose, to determine the wear rate of that edge. Many radiant manifolds use mini ball valves for balancing. This is usually "good enough" considering the flow rate and amount of adjustment you need. Nicer ones have equal proportion disc type valves and instructions regarding the flow versus turns on the stem. The new Wirsbo actually have a clamp on digital meter to set flow! It all depends on what you are balancing, flow rates, and how accurate you need to be. Use a flowsetter or balance valve with gauge ports, if accurate flow control, and longevity are important. hot rod
  • Arthur Arthur @ 12:46 AM
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    Ball or Goble Valves ?

    Hot Rod, Totally agree with you, yes good point, A true isolating/regulating valve has a taper valve onto a taper seat and also has provisions to preset the valve at a certain point and allows the valve to close for isolation yet only open again to that set point. This means the presetting is not lost when used to isolate. Generally these are in a y configuration. The means of presetting varies from brand to brand but still gets the same result. Good quality ones have a s/s seat and valve. The good ones also have provision for taking pressure reading across the valve to measure the pressure drop so the flow can be adjusted on the preset.
  • Tony Conner Tony Conner @ 8:43 PM
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    Unless...

    ...it's a V-port ball valve, the control you get with ball valves in throttling service is not very good - pretty much like you get with a gate valve. Water column blow down valves are not really in a throttling-type service. They're not slammed open/closed, but any of the ones I've seen are opened/closed pretty quick. It's the same with ball valves used for TDS control - they're operated by an electric motor actuator thru a worm-gear. They drive open, they drive closed. I don't think it really qualifies as a throttling service. Full-port ball valves are un-necessary in most applications. The reduced-port valves have very little pressure drop across them, because they're so short in length. If you're suffering wear due to turbulence, then I'd say the whole line is undersized for the flow it needs to handle. The only time I've used full-port valves is for isolation valves on a pressure reducing or temperature control valve station. The refinery & petro-chemical industries use full-port valves a lot, because they have lines that must be periodically "pigged", and the pig would get stuck in the reduced valve section. I have actually seen a line eventually leak because of throttling by a ball valve. Ever throttle a ball valve in water service where there was no downstream pipe or nipple? You've seen how the water shoots out at an angle. You get the same effect through the valve, whether there's any downstream piping or not. A 1/2" copper water line, throttling city water 24/7 developed a leak in the wall of the pipe, a few inches downstream from the valve. The water velocity caused by the pressure drop across the throttled valve eroded a hole in the copper pipe. It took almost a year to do it, but it finally wore through. I doubt low head circulators would move water at high enough velocity in a closed loop heating system to cause this type of leak though. It would likely take a LONG time.
  • Bob Bob @ 9:43 PM
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    Blowdown

    If you have ever blowndown a water column on a high pressure boiler you'll see why, the glass will not be cleared if valve is opened to swiftly. This is not an issue on low pressure boilers. Auto units can be set to not open fully, to act as an valve and metering block in 1 unit.
  • Tony Conner Tony Conner @ 9:16 AM
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    There's A Difference...

    ...between opening/closing slowing, and throttling. A throttling service is one in which the valve is set partially open, either automatically, or manually and adusted periodically, over a span of time that can literally be years. (Steam PRVs on deaerators would be valves in throttling service.) Steam boiler gauge glass & water column blowdown, and bottom blow down won't fall into this catagory. These valves are opened with varying degrees of speed, to full open, then closed. Any throttling that occurs during the valve operation is coincidental. Any of the ball valves I've seen in CBD service are open/closed operation, driven by an electric actuator, through a worm gear. They drive fully open, hold for a few seconds, then drive shut. Unless they're V-Port ball valves, I can't see them A/ lasting for more than a few weeks, and B/ being accurate enough to control properly. I doubt that even the V-port units would be accurate enough for CBD control. I've tried ordinary globe valves for CBD control (we were in a jamb, waiting for the proper Hancock needle valve to arrive), and they just don't provide close enough control. Nobody in the plant could adjust the valve to the degree necessary. If the TDS was running high, and guys adjusted the valve, even as slightly as possible, the next water test in a few hours would show the TDS value below the low range. Adjust the valve just slightly closed - off the top of the range a few hours later. The needle valve showed up, was installed, and then things were back to normal. The control range was easily maintained.
  • Murph' Murph' @ 9:33 AM
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    to not throttle ball valves

    Is a myth created by the companies that make globe valves!! how many do you find failed? just because velocity does not make them fail, buy American!! Murph'
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