Valve Definition and 235 Threads

A conceptual problem related to a design I'm working on: If I use a pump to suck air out of the top of a vertical pipe, with the bottom of the pipe in water, I can only make the water rise around 10 metres inside the pipe, if I produce a perfect vacuum. Now let's say the pipe was 100m long and...

Homework Statement A well-insulated tank of volume 6 m3 is divided into two equal volumes. The left part is initially filled with air at 100 C and 2 bar, and right side cell is initially empty. A valve connecting two cells will be opened so that gas will slowly pass from cell 1 to cell 2. The...

Hello everyone! I am new to these forums and glad to see a great community helping out each other. I have a question regarding a solenoid valve design. What should be the design ethics and safety considerations for a 240 volts AC connected solenoid valve that is used for a cryogenic vessel...

I have a centrifugal pump 50 m above a vessel, I’m pumping water in at 4 bar gauge into this vessel. I then close a valve to cease pumping ensuring no air enters the system.My question is, if I now open that same valve to atmospheric air this time, will the water exit from the pipe through the...

So I've decided to subject my little Suzuki Samurai to some home-spun garage surgery. Converting to a full sequential MPFI. (and doing a little porting along the way). Now for the physics(ish) bit. See image of intake cutaway. The blue arrow points to the sharp ('cut -off') trailing edge of the...

I've come across a gate valve schematic symbol that I can't find any information on. It is the standard symbol with a small arrow pointing out from the side of it. I am working with an air system, and it uses two valves of this design according to the schematic. Can anyone tell me the specifics...

Homework Statement In the image I have included it shows a diagram of the setup we used in a lab and you can see that at the right hand side there is a butterfly valve so I am wandering what would be the use of the valve in this situation. Since its after the compressor I was thinking that its...

Homework Statement I just did a lab experiment that involved recording the heights of manometer tubes placed in different locations along the compressor in order to calculate pressure drops, air mass flow rate, isentropic efficiency. An electric motor provided the power to drive the compressor...

I am at a loss for trying to find this part, it seems like only 1 or 2 manufacturers produce this, But I'm sure it is more common than that. This is an attachment that goes on to the inlet/outlet of regenerative blowers, and with a solenoid, allows the output port to switch between vacuum...

Homework Statement A valve is required to regulate the flow of natural gas. Details of the gas are given in table below. It can be assumed that the pipe size and the valve size are the same [i.e. piping geometry does not have to be allowed for]. The chosen valve type is the V250 rotary ball...

Homework Statement Calculate the equivalent choked flow of propane through a particular valve if the choked flow of natural gas through it is 10 litres s–1.The relative density* of propane is 1.45 and that natural gas is 0.65.Homework Equations Kvf = qv (SQRT d/DeltaP) ...1 d is fluids...

would an air check valve help lift by preventing air presure backup through the lift fan?

Hi folks, I have a question regarding centrifugal compressors when a relief valve is included in the system. Allow me to explain... There is a centrifugal compressor supplying air to an aircraft engine. As altitude varies, the compressor provides enough pressure up to altitude "X" for the...

Dear all, I'm wondering how a control valve can control pressure and flow rate. I understand that a control valve in a pipe induces a certain pressure drop but I don't understand how this affects flow rate. I'm disturbed with the continuity laws which states that the total flow rate between two...

In fluid dynamics there is a duckbill check valve to prevent the reverse flow. In EM wave an antenna emmits/receive at the same efficiency. Is there anyway one can make a check valve for antenna so that it emmits more than received or vice versa...or perhaps emitts without even receive?

Hey, I'm working on a project to build a drone which is powered through air jets. The drone needs a valve control system which can control the flow rate (hence the thrust) going to each nozzle in order to adjust it's altitude and stabilty. I need to set up a circuit which can electronically...

Hi, I am following this particular article from machinedesign.com about properly sizing a pneumatic system - http://machinedesign.com/archive/right-sizing-pneumatic-motion-systems In the section Valve Exhaust Port, he does a calculation for the valve loss coefficient and arrives at 1.833 cfm...

I am developing a machine which consists of a horizontally mounted cylindrical drum, where the door is front mounted, top opening pneumatically actuated (Picture enclosed). The door is lifted up by the pneumatic cylinder. Now there is an obvious possibility of the door crashing down if the air...

Homework Statement There is a cylinder of oxygen connected to a valve (A) and then to connected to a regulatory valve. The volume of both valves and the pipes between them is Vr and can be disconsidered in regard to the cylinder's volume. The oxygen can be considered a perfect gas with...

Hi I know what 'RPBP' valve but do not know how it works? Please explain it's function with picture, if possible. Does it work like Spring-Loaded Check Valve? it seems it is combined of two Spring-loaded Check Valve, But why two and how are assembled?

Hi, Homework Statement I have the following question in my course work. What I do not understand is why it provides the relative density of natural gas?! Calculate the equivalent choked flow of propane through a particular valve if the choked flow of natural gas through it is 10 litres s–1...

I'm looking for an example of CFD analysis on a pressure reducing regulator. I think may be fairly complicated because the main valve position is not fixed but rather controlled by the pressure differential acting across the valve, the main valve spring, and the load spring minus the pressure...

Hi guys, I am having quite the struggle finding a good resource to explain the difference between the magnetic force associated with moving charged particles (Lorentz Force) and just the regular force exerted by a magnetic field on a magnet or ferromagnetic material. I am trying to apply this...

Hi everyone Would like some help here. If I draw a control volume across a valve that I can control the flow area to, and I know the temperature and pressure upstream of the valve, I will know its enthalpy:in. High temperature liquid going through this valve supposedly changes to steam due...

Hi All... I'm in the process of restoring an old Eddystone 730-1a receiver (all valves for you younger folk) and the service manual gives the test point voltages based on a 20k/Volt meter. I realize that some, if not all of these voltages are relative to a high impedance source and the 20k/V...

I have a commercial fishing boat with a gillnet reel,basically a large winch. The reel is powered by a hydraulic motor and a chain drive/sprocket setup. It uses a reversing hydraulic valve with load checks,I think they are called. When the motor is activated/deactivated it comes to a complete...

is there any difference and why ? I have a ball valve with 100 psi jet fuel on one side and atmosphere on the other end ? Is there any difference if o have 100 psi and the valve all the way open vs. say 200 psi and only half way open . Please explain ?

does anyone know what the boundary condition is for a closing valve using the wave equation pde?

I have a tank which has a Pressure Relief Valve (PRV) connected to the atmospheric vent (Carbon steel with friction coefficient of 0.14). The PRV is opened at Set pressure of 30 PSIG and has a capacity of 60,000 SATSTM (I assumed it to be in lb/hr). I am trying to calculate the discharge...

I have a problem with Discharge Coefficient of Valve equation which is described in book 'advanced water distribution modeling and management' let me say: I think the expression V^2 in Discharge Equation (P. 618 of the book mentioned) is extra and the equation must be changed to: I)...

Homework Statement Two closes containers are connected by a valve, which initially separates the containers from each other. C Container A has 8.00 L of H2 at 3.00 atm and temperature 400 k. Container B has 6.00 L of O2 at 4.00 atm and temperature 400 k The valve is opened, the gases mix, and...

Is there one way valve that allows a liquid flow in one direction and prevent air flow (under pressure) in the other direction? Thanks for any help ...

Hello, I read something about the pressure drop across a valve and it was specified this is a singular pressure drop equivalent to K*U²/g (Borda formula). My question is, can we used the Bernouilli formula for a permanant incompressible flow to determine the flow rate function of the pressure...

So i want to create a container that is part of a system that already actively cools things that touch it. This variable cannot be changed. What i need is a container with some sort of valve that automatically opens up at a certain temperature. Thereby allow air to circulate and reduce the...

Hello all! I am designing a machine which consists of a horizontally mounted vessel which has a movable lid. The lid is moved up-down with the help of a pneumatic cylinder & is guided on linear bearings. My question is during maintenance, when the lid is UP, and for any reason there is a...

Hey Guys! Anyone able to help out here? I have already happily solved for T2 = 369.91K and m2 = 11.492kg However, for question 2.3, I'm terribly stuck. I'm not even sure what to make my control surface. How can I relate pressure outside the valve with the two thermodynamic states I have...

I have a project for school and need to make a hand water pump. The thing is, it needs to be a "mini" pump. I will be using 2 mini 1 way check valves and a t fitting, but the problem is i cannot find a way to make the actual piston pump. I also need a spring to draw the piston back up so i can...

There is a liquid phase homogeneous reaction going on in an CSTR, which operates at 4 atm. Is it necessary to have pressure relief valve? If so, what will be vent out when the pressure exceeds, since it contains liquid only?

Hello all, I am under the process of designing the Pressure safety valve ,the core component of PRV is spring.just i want to know about the spring design .For eg my max allowable pressure is 5 bar, then i want to set the spring to stay uncompressed at 5 bar and the spring has to compress after...

hi, i want to derive a model of digital control valve. i don't have physical valve with me. still i have to develop such a simulator which can behave the same as the digital control valve. the working concept of digital control valve is little bit different than normal control valve. here is...

I am struggling with calculating the valve size from a V250 rotary ball valve by Fisher Controls International. The below table states that natural gas is running through the vavle and the following properties apply:Natural Gas Required volumetric flow rate [@ STP] 2.8 x 106 litre per...

< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > The max flow rate through a control valve with an equal percentage characteristic is 10 m3/h. If the valve has a rangeability ratio of 50:1 and is subjected to a constant differential pressure, calculate...

I'm having some difficulty determining which type of valves the following are. I believe the first 1 is a pressure relief valve. However i don't understand the sectioning philosophy, some things just aren't sectioned that i'd expect to be, therefore I'm finding it hard to gauge which surfaces...

I am working on a high pressure (280 bar - 4000 psig), high temperature (250 C - 480 F) system and I need a safety device that can vent through a 6" diameter connection. I would love some feedback on viable and practical solutions for this application. I am considering a valve, but I am not...

I am scratching my head on this question. PRV is supposed to create a closed system requiring a thermal expansion tank. But at the same time PRV is not considered a backflow preventer. How can both be true?

Hello all, I have a Varian M4 diffusion pump that has a 6 inch diameter opening at the top, is it okay for me to connect that to a reduced size opening like just 2 or 3 inches diameter so that I can use a smaller valve? I am only trying to pump down a cubic foot or two sized chamber. I am...

How we can incorporate valve lift and variable flow rate in compressed air engine Mechanical power = air power torque * angular velocity = pressure * flow rate

In some motorbike engines, I notice there are two springs (inner and outer) for a valve. Why do they have to make it two ? Thanks

Hello, I am Primarily a Software Engineer, but have some background knowledge from my A-Level and Uni days. However, I have the following problem. I'd like to find out the rate of change in pressure across a valve. Here are the things I know about the system: Cv at 100% open = 0.004 (I...

If using diffusion pumps (2 or 3 in series) to achieve ultra high vacuum, how do you hook them up together, for example adding them onto a system like in the provided picture? Would you use T-connectors to put them all on the same input and output valves or would you have valves for each pump?