Valve Definition and 235 Threads

  1. M

    Finding out the time duration for which intake valve remains open

    I set out to find out how many seconds it takes for a 4cylinder naturally aspirated diesel engine to complete 1 cycle(4 strokes): I considered a tata indica model max power:53.5PS@5000rpm therefore 5000 rev per min or 83.3 rev per sec now it takes 0.012 seconds to complete 4 strokes or 1...
  2. B

    Control Valve Modeling: Get Physical Representations & Convert to State-Space

    [b]1. I'm carrying out the modeling of control valve using Physical method as part of my project. The first step is to get the physical model representation of a valve and then carry out the modeling. Secondly, I need to incorporate friction in the modeling to see the effect. I've seen a number...
  3. D

    Test to find pressure drop through valve?

    Hi all I am trying to design a test that can be carried out on a valve to calculate the pressure drop and flow coefficient through said valve. i need to have a 6 bar inlet pressure into the valve and the ID of valve will be 50mm. the fluid i am proposing to use is water. My design is to have...
  4. A

    Where to Find Small, Battery-Operated Air Valves for Arduino?

    Hi guys, I am looking for a small and light air valve that can be activated by the arduino platform and can run on batteries. Once the valve gets the “go”signal it needs to switch (speed doesn’t matter) from a closed to an open position. The pressure to handle is low, i.e. <2 bar. It only needs...
  5. E

    How Fast Can a 16-Inch Butterfly Valve Actuate?

    Hello; just need approximations here. 16 inch buttterfly valve with separate environments on each side. side one: clear water at about 8psi; side two: air at about 33 psi; Consider both pneumatic and electric actuatiion under ideal conditions.What is the approximate fastest time to open...
  6. C

    Shear valve Design. Wall thickness at break point.

    Hi. Situation: A pipe with a cut out so it will break when a shear force is exerted at the top of the pipe. The break point is at the cut out and the the force is impact in lbs. What is the wall thickness(or cross sectional area) at the cut out point? I know i may be missing variables...
  7. D

    Calculate the flow coefficient and pressure drop through valve?

    Hi I am wondering would ye be able to help me out? I am instructed with the task of calculating the pressure drop and flow coefficient for a valve. Please see basic diagram attached for layout of valve. I need to find the pressure drop and flow coefficient when the ram is closed at different...
  8. O

    What is the Standard for Valve Pressure Ratings?

    Hi, I have a question. Glove Valve PN16, JIS10k , ANSI 150#, AMSE, all they equal same, in withstand the steam pressure? I heard RN16 stand for 16bar pressure, but it's for steam too? I'm confuse.. million thanks if anyone would teach me please.
  9. M

    How Does Closing a Valve Affect Flow and Pressure in a Pipeline?

    help please -- how does a valve work ?? how does a valve work ?? when in a uniform cross section pipeline a valve is closed it reduces d opening due to which the area decreses and as area decreases flow should increase A*v=constant so how does it work ? please explain mentioning the...
  10. B

    Actuator-solenoid valve circuit

    So I designed a circuit. It is controlling a pulsating actuator-solenoid. I used a power BJT as shown in attachment. Now I have a problem. As you can see all 4 circuits are in parallel. As a consequence, all 4 solenoids have one lead in common. When I test each subcircuit, it works...
  11. S

    Valve spring in engine, why the closer coil must be down?

    In engine, there is valve and the valve spring. If you have ever look at the valve spring before, then you will notice that one end has its coil closer together than the other end. So a valve spring is a kind of progressive spring. In almost all engine repair manual I read, the instruction is...
  12. Z

    Temperature change across expansion valve?

    Homework Statement Refrigerant 134-a enters the expansion valve of a refrigeration system at 160 psia as a saturated liquid and leaves at 30 psia. Determine the temperature and internal energy changes across the valve. Homework Equations Δu=cv*ΔT The Attempt at a Solution I'm...
  13. S

    Determining flowrate (GPM) through a partially open gate valve

    Hello all, trying to figure this out. I work at a shipyard and operate/maintain the drydock. The discharge tunnel that flows water out into the ocean has culverts about 24.5' x 15.5' x 8'. Connected to the bottom of the culvert is a 48" pipe that goes to a gate valve of the same diameter. If I...
  14. M

    Aircraft Air Bleed Valve function

    Hi guys, I'm relatively inexperienced with aircraft engines and I'm keen to understand how the actual mechanism for bleeding air from the system works. I know that there are bleed valves on a plane, which remove hot air from the system and roue it to other areas to take advantage of this...
  15. M

    Pneumatic Valve and Orifice Issues

    I am working on a problem trying to find out why a 0.010” orifice can be used to open a pilot actuated, spring return pneumatic 5/2 directional control (spool) valve, but a 0.0045” orifice only seems to work intermittently. The air system that I am working with is 100 psig. The air enters...
  16. wukunlin

    Toilet: Removing the Cistern Valve Blocker

    So the toilet in my parents bedroom is all hissing and annoying so I decided to try fix it for them. I bought a new cistern valve to replace the old one, when I removed the old one i noticed this thing circled in the attached pic. I'm not sure what it is used for except it prevents the...
  17. M

    Air pressure and water height vs valve operation time

    Ok, so I am trying to build myself a small water tank (about 1 L) with 2 tubes coming from the top. The first one goes all the way down to the bottom (thus in the water) and acts as the outtake. The second one is an air intake where the air pressure is regulated, say 5 psi. Now, I want to be...
  18. B

    Relation between flowrate and butterfly valve opening

    is it right to say that valve opening for both ball & butterfly valve is directly proportional to flowrate passing through it? say 100 m^3/hr at 100% opening 50 m^3/hr at 50% opening?? thanks in advance..
  19. T

    Measuring flow through a balancing valve

    My company installed a number of balancing valves (Tour & Andersson, STAD) in a central heating system. These valves are used to measure the flow (in this case water). According to the valve's specs it should be installed with a certain distance of straight pipe both before and after the valve...
  20. T

    What not use a proportional relief valve?

    There is this talk in the New York Times about venting valves : What not use a proportional relief valve ?
  21. F

    Consequences of Incorrect Valve Timings on Your Engine

    What would happen if an amateur mechanic decided he wanted to adjust his valve timings outside the factory specifications and screwed up? What would happen? What can incorrect valve timings do to an engine?
  22. R

    Check Valves: Questions Answered

    http://en.wikipedia.org/wiki/Check_valve from the above wiki link I have understood basic concepts on Check Valves Suppose I Heat a gas ( air ) in a closed vessel. It's temp and pressure increase. As soon as the pressure reaches ( or exceeds??) the cracking pressure , the valve opens and...
  23. T

    Failure probability of a valve in one year.

    Hi all. Probability definitely isn't my specialty, and I've run across this problem at work. There's one gate valve that isolates two 2400 psi hydrogen gas banks from each other, and I'm trying to find the probability that it fails in one year. I've done some digging and found failure rates...
  24. R

    High Pressure Valve Opening - Collision Mechanics

    Hello all - this isn't a homework question; it's a real problem I'm struggling to solve. Apparently I'm being a bit of a mechanics 'tard, so any help would be appreciated. I have a high pressure reservoir (~60MPa) sealed off from a low pressure area by means of a metal plate. The plate has a...
  25. E

    Pressure relief valve safety considerations during design

    What are the main safety considerations during design of a pressure relief valve? and how would you go about diagnosing if they are incorrect? Is the following correct? Orifice diameter for a fixed pressure - How to diagnose if it wasn't correct? What effect would a incorrect system...
  26. B

    What kind of valve will do this?

    I need a valve that will pressurize a system, then leave the system pressurized for a time, then exhaust the pressure on command. I need it to be easily portable and quite small, and will run at pretty low pressures. What kind of valve would do this for me?
  27. Drakkith

    Dynamic Pressure Valve for Heated Gas Release

    Is there a valve that can be set to open to let hot gas out at a certain pressure, and then close once the pressure drops back down? Edit: Sorry, I'm looking for a valve that will let the pressure build up to a high point, then open to release the gas until the pressure is released, then close...
  28. S

    Engineering Motor control design for air flow valve

    Homework Statement build a circuit that open and closes the valve using, electronic components Homework Equations none known yet The Attempt at a Solution this is my first try
  29. U

    Rockwell hardness of valve lifters

    Hey guys, I have a set of rocker arms that I converted from a hydraulic to a mechanical adjuster and I am having problems with the adjuster screw I am currently using. Whats happening is that when the adjuster screw hits the valve lifter, its digging away at the top of the lifter causing a...
  30. Q

    Water valve for a cylindrical container

    I need help designing a mechanism for quickly releasing water through a tiny hole on one end of a thin cylindrical pole by a switch/button/etc on the other end. I have thought of one way to do this and drew an illustration, which is in the attachment. But I'm not sure if when the bar is covering...
  31. N

    I need a valve for the quick release of air, help please?

    hi, im not sure that this is the correct category, or even the correct forum, but I am sure someone will answer my question, i am intending to build an airgun, which uses a bicycle pump to build up pressure inside a treacle tin (hahaha), and i need a valve, so that when i have compressed...
  32. R

    Valve, Gas fluid flow question

    Hi all, I am new here and need your help. After sudden opening of a ball valve with cross section area of 10 mm come to an blow up (explosion) of the 2" pipe. (before opening) Up stream the valve was the gas pressure 190 bar during downstream the pressure was 0 bar, however it was air inside...
  33. J

    Can a Valve Create a Time Lag and Prevent Water Mixing in a Pipe System?

    Hi guys, Right, here is the situation. Consider a long coil of pipe containing water with a thermostatic valve at the outlet and a valve (this is the valve in question) at the inlet. The inlet is gravity fed by a large reservoir of water and the question is this: as the water leaves the...
  34. J

    What Type of Valve Should I Use to Control Water Flow in a Heating Process?

    Hi all, Right, this may be a bit hard to explain but I'll do my best. Hopefully attached is a sketch of the situation. The water flows from the tank into the "rigid container" through valve (1). This tank is then heated until the water reaches boiling at which point the thermostatic valve...
  35. A

    Are My Mathematica Calculations for Pneumatic Gun Velocity Accurate?

    Ok, so I'm building a pneumatic gun with a barrel 0.3m long, operated using air pressure. The barrel is square, 1cm on each side, and the projectile is a 5g elongated cube. I wrote some code in mathematica to plot the speed in m/s versus the air pressure in psi. I was wondering if anyone...
  36. V

    Reducing Water Velocity Without Reducing Flow: Finding the Right Valve

    Hi all, Need a bit of help with a problem. I have a 4 inch pipe (carrying water). On the end of this 4 inch pipe is a 2" orifice. Now flowing through this orifice is water at 50L/s at a head of 100m (790 GPM and 330 feet). Basically as you can imagine, there is a lot of energy behind this...
  37. D

    12 VDC 4-Way Reversing Valve Source

    I have had trouble finding a source for a reversing valve manufacturer that carries a 12 vdc solenoid coil Any leads would be helpful. I have tried Danfoss, Ranco, and Parker, but to not avail. Thanks in advance for the help. D.
  38. S

    Is There a Vertical Water-Only Inlet Valve?

    I am looking for a valve that will let water into a system, but will not let the air out. The valve however will be placed vertically with water entering from the top. Trying to add any water into my system has only created air bubbles. If you have any other suggestions on how to do so, or if...
  39. P

    Calculating Exit Temperature of Steam Through a Valve

    Homework Statement Steam at 8 MPa and 500 C flows through a valve, where it exits at 100 kPa. What is the exit temperature? Homework Equations ? The Attempt at a Solution Looked up both pressures on the steam tables. Not sure how to correlate them as I have never used them before.
  40. T

    Pressure to lift a safety valve.

    I'm not sure how to work this one... The spring on a safety valve can be compressed 15 mm by a load of 700 kg. In it's working position the compression of the spring is 22 mm. The combined mass of the valve, spring and spindle is 17 kg. Valve diameter is 80 mm. Determine boiler pressure...
  41. S

    Building the Valve Library: A Community Effort

    Hi I hope that this won't be treated like spam or something. I just used search engine to find place where I can find people who may be interested to help me building something that I call "valve library". I started small website with intention to create online place where You can find all...
  42. 0

    Is Choked Flow the Key to Designing an Effective Relief Valve Tailpipe?

    Hi, I'm a final year master's student doing a study on relief valve tailpipe design for my final year project. The system which the relief valve is fitted to is a high pressure breathing air gas cylinder (300 bar) on board a large ship and it vents to atmosphere via piping which can be...
  43. J

    PROBLEM: Turbine connected via adiabatic valve to air supply

    Homework Statement Air turbine used to drive a application in a machine shop is supplied with air from the factory air supply main where the conditions are 0.6 MN/m^2 and 31 ºCthrough an adiabatic throttle valve which reduces the pressure to 0.3 MN/m^2. In the turbine the air expands...
  44. P

    Calculating Pressure Drop Across Valve in Horizontal Pipe

    Hi, 20m straight length horizontal pipe (60 mm internal diameter), steam flows at rate 0.5 kg/s, at midpoint there is a valve in the line. inlet pressure to this section of line is 5 bar (gauge), pressure at end of line is 3 bar (gauge). mass quality of steam is 0.8 and 2 phase flow occurs in...
  45. V

    High Speed Pneumatic Valve: 200+ Times/Sec, 2-Way, 12bar, 0.03 kg/sec

    Hello everyone Iam doing my M.S in aerospace engineering at Chennai, India. I require a high-speed operating pneumatic valve that can open and close more than 200 times a second. Kindly allow me to know if it is possible to acquire such a valve with these additional specifications also: > 2...
  46. J

    Powering solenoid valve in hazardous area

    Hye everyone~ I am Jesse and I'm new to this forums :smile: and i really need your help so let's get straight to the prob.. can anyone tell me what are the choices i can use if i want to power up a solenoid valve installed in a hazardous area. I've heard about powering it thru system...
  47. T

    What is the force on a poppet valve due to expanding air?

    I need help with the following problem. I have attached a rough sketch showing what I'm looking at. Basically a popppet valve is closed over a vent. It is then pushed open by a force applied to the valve by the pushing rod. Their is a spring on the rod resisting this and providing a force...
  48. I

    Calculating Net Force on Valve in Pipe: Pressure Difference Analysis

    if i wanted to figure out how much net force/torque is applied to a regular disk type valve in a pipe as a function of the pressure difference on both sides of the valve what would i have to do/where would i have to look?
  49. O

    Piston valve Springs in diesel engine.

    Hallo, I'm looking for explanation for the fact that in many diesel engines we have two springs supporting the piston valves such that one is exterior and the other interior and they have opposite helical direction. Also if anyone have a link or any information it would be very helpful.
  50. S

    (Thermo) Tank of N is heated, valve opened, find time duration

    Homework Statement A nitrogen gas-liquid mixture is in a 20 cubic foot tank at a condition of 161 R with an initial quality of 0.1. Heating occurs at a rate of 10,000 Btu/h until the pressure reaches 100 psia. At this condition the BHE safety valve opens and maintains a constant pressure as...
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