Q:Liquid propane leaving the reflux pump of a distillation column flows through a 3.5 in ID pipe at a flowrate of 90 lbm/s. There is a flowrate control valve in this line, and it is set such that the pressure drop across the valve (delta)P=15 lbf/in^2. Upstream of the valve , the pressure P1=18 bar and the temperature T1=310 K. Assume there is negligible heat transfer with the surroundings and that the density of the liquid does not change significantly.a) What is the kinetic energy change across the valve?b) What is the enthalpy change across the valve?c) What is the temperature change across the valve?d) What is the entropy change across the valve?

If there is NO change in the density of liquid propane as it passes through the valve, and if the size (area) of the pipe upstream and downstream of the valve is the same, then a) there will be no change in the velocity of propane, hence there will be no kinetic energy change. b) this is a process of throttling, with no change in kinetic energy, hence there is no change in the enthalpy. c) temperature change can be determined using the detailed property table of propane, but if it is an almost-incompressible liquid, then this too, will be negligible. d) dh = T ds + v dp. Since there is no change in h, integrate this along a constant h line from inlet to exit (upstream to downstream) and you will get ds = -(v/T) dp. Since p reduces from inlet to exit, the change in entropy will be positive. This is as expected. If we assume density (=1/v) and temperature (T) to remain constant, then the change in entropy will be s_downstream - s_upstream = (p_upstream - p_downstream) v /T.

Q:We have a main gas valve outside and there's a gas valve by out air condition and we want to know which way if off and on .. Does anybody know !!!

Generally speaking the valve has a handle that pivots from parallel, to perpendicular. Open is in line, or parallel. Closed is perpendicular. If it's a rotating handle, then the valve stem will be all the way in when closed, or all the way out when open. The valve stem is located in the center of the wheel that you would turn. Hope that works for you.

Q:12 valve

Un plug the vacuum hose on top of the valve, loosen and remove the big tube nut on the bottom of the valve, I have found if you hit it sharply with a hammer 3 or 4 times before you try to loosen it won't break the valve off, once the tube nut is undone remove the 2 bolts holding the EGR valve to the intake manifold. Remove and discard the gasket and install the new valve in the reverse order. If the tube nut still won't come loose try heating it with a torch, if it's really rusted on you might have to replace the EGR tub along with the valve.

Q:I own a 2wheel drive 2003 Hyundai Santa Fe 4cly. The engine light was on the code P0401 came up which is the EGR valve. I had it changed out the engine light came back on after I had made it almost home. I took it to auto zone same code came up that made me take to the shop for repair in the 1st place. Ugh. Please help! What's the problem???

My vehicle is throwing a P0401 code. I was going to replace it, but instead I am going to clean it and replace it. I know the mechanic will want to replace it and charge me well over $100 (I'm seeing the part go for around $52-$55). THe car was recently serviced with the valve cover gasket replaced.

Q:Beneath my kitchen sink are two shut off valves for the water; one for hot, one for cold. The hot water valve has never successfully stopped all water flow, so we've always resorted to shutting off the main line. Well, now that's not working. We shut off the main water line to the house, all water everywhere is non-functioning except for the hot water pipe beneath my sink. It's now causing the faucet to constantly stream water, so it's something we have to resolve ASAP. I'd like to avoid calling a plumber, but my knowledge in such areas is very limited. Can anyone give me any decent suggestions? For the record, I did take apart the faucet fixture just in case, thoroughly cleaned it, and replaced all of the washers I had access to; but we only just bought the faucet in September, so I can't see a worn washer as being the problem. I also tried to tighten the nut behind the handle on the valve. It didn't effect the dripping.

Leaky Water Valve

Q:I had a doctor who was suspicious of me having a heart valve problem. I don't want to be on medication for the rest of my life. I only want to change my diet, pray, exercise, and meditate. I don't believe the doctor has that cure for that problem that's if it was a heart valve problem.

It depends on what sort of heart valve problem you have, how bad it is, and how bad the symptoms are. Sometimes you don't need to do anything special except watch the diet and lifestyle, sometimes you need medicine, and sometimes the cure is surgical repair or replacement of the valve. I think prayer is a fine thing to help, but the Lord also gave us the skills so doctors could provide something a little more physical. If your heart valve problem is bad enough, it can cause damage to your heart and the rest of your body that all the prayer, diet, exercise and meditation in the world won't help fix. However, as a patient, it's always your decision if you want to take the doctor's advice or not. Otherwise you could find yourself dead, and explaining to God why you chose not to take the help He provided for you. So before you go making any decisions, you need to wait until you find out what the entire story is. Then weigh up all your options carefully,and decide.

Q:In the very near future I'm having valve replacement surgery. I haven't yet been told the risks or the recovery period, does anyone know the risks or the recovery stages and how long recovery takes?

Valve replacements actually have very low morality rates like 1-2%. There are always risk's with surgery though, such as blood clots or irregular heart rate. The recovery in the hospital is generally 5-7 days, and then it can take anywhere from 8 weeks to a year to feel recovered.

Q:1995 Firebird - with digital EGR valve, I think when the engine is at idle, it would be closed, I think.Anyway, this EGR valve has 3 holes that open up whenever.I noticed that the plastic housing on them is melting a little, which probably isn't anything.but I felt around it, and I feel a little air coming out, not from the gasket part, but maybe it has a leak in one of those solnoids somewhere.My cars been idling really ruff, do you think a leak in that would cause it to idle ruff?when I drive, it's fine, runs smooth, but stopping it idles ruff.I just bought that EGR valve 2 years ago, I don't know why it would melt.

Take the EGR valve off and see if it is internally caked with carbon. Also look at the ports it lines up to on the plenum and see if they are also clogged with carbon. If they are, remove the air intake tube from the throttle body and open the throttle plate. See if the intake plenum is also clogged with carbon. If so, and I think it is, you will need to get yourself a cumbustion chamber cleaning. Those 90s GM cars were bad for this. This will make it idle rough, and also lack as much power as it should have.

Q:my mechanic did a valve clearance check and said it was OK and when I asked him about the clearances he said that they were 6 thousands and 9 thousands however in my book the measurements are different they are as follow: ( i don't understand what he meant by thousands)inlet: 0.10~0.140.15~0.19 exhaust: 0.14~0.190.20~0.24so did he just make it up or did he get the wrong measurement.

Klx250s Specs

Q:Can I make a heat pump straight A/C ?Or some hints how to replace the reversing valve without reclaiming freon

problematic thing. research from search engines like google. just that can help!