Questions tagged [valves]
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83
questions
0
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1answer
32 views
Head loss coefficient for a valve with respect to both the open position and flow rate
This question talks about the head loss coefficient for a valve, i.e., $K_{L}$ for $h_{L} = K_{L} V^{2} / 2g$ where $h_{L}$ is head loss.
First, head loss coefficient for a valve with respect to the ...
3
votes
2answers
73 views
Why do pneumatic valves need both a Safety Relay and an Air Dump to be safe?
If air dumps safely release pneumatic pressure from an industrial machine when an E-Stop is pressed, why is it also standard practice to cut electrical control power from the valves with a safety ...
0
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1answer
35 views
Is there any way to quantify the rate at which pressure is relieved in a reactor?
If a pressure relief valve is open, is it somehow possible to quantify the rate at which the pressure in the reactor will decrease?
0
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0answers
45 views
Which of these systems should reach a better vacuum?
I'm trying to find a cheap manual vacuum pump for a sample transportation container that carries oxidizable samples of thin-film magnetic materials.
They already have a 15 nm Tantalum layer on top, so ...
0
votes
1answer
33 views
Is there a valve that will only open when input pressure is above 3 atm including when the downstream pressure is also 3 atm?
I want to use an external gear pump to pump air into a combustor at a design pressure of 3 atm.
Unless i use a valve that opens at threshold pressure there is no compression - the air exists the pump ...
1
vote
0answers
28 views
Valve solution for mixing external air into a closed loop climate controlled air circulation system
I'm looking for an electronically controlled air valve solution which would provide a way to mix external air into a closed loop air circulation system used for climate control in an enclosure. The ...
1
vote
0answers
43 views
What's the name of the valve that opens once pipes are mated?
I am building a wastewater system for my van (ie low pressure) and would like removable tanks for ease of emptying. I can shut off the inlet but would like to be able to drop them and automatically ...
0
votes
0answers
34 views
Controlling flow through an output pipe
I wish to limit my flow through the output to a certain exact value. In this case to 10 lpm, what method or valve can I use to this task?
At the moment the flow keeps on fluctuating between 10.1-11.2 (...
0
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0answers
29 views
Adding electric control to industrial hydraulic disk brakes
I'm trying to electronically control the service brakes on some construction equipment, in addition to maintaining the normal brake pedal functionality. The disk brakes are controlled by the valve ...
0
votes
2answers
52 views
How to simulate open and close and control valve using a simple controller
I have successfully developed a mathematical model for my physical system. My objective is to control the mass of gas in and out of the system.
The mass flowrate is given by:
$V_f = C_d.\sqrt{2.\frac{\...
1
vote
1answer
82 views
What kind of solenoid valve should I use for vacuum?
I'm currently working on a project in which I have to control 2 solenoid valves with arduino to switch the suction of a vacuum pump from one tube to another one (tried to explain it on the photo), I'...
0
votes
1answer
64 views
Valves and plumbing size
I'm building a liquid rocket engine and we're using kerosene and oxygen as our propellent. Now my question is what pipe size should we use? My flow rate for kerosene is 0.160 Liters per second and we ...
0
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0answers
46 views
Selecting a water pump for low flow and 1 Bar pressure
I am designing a small automatic drip irrigation system. There will be about 10-15 drippers. Flow through the system will be about 1 l/minute, but this may change if expanding or reducing the system. ...
0
votes
0answers
30 views
Approximating volume flow based on valve opening
I want to approximate the volume flow going through heating/cooling units, but all I have are valve openings (unit=%). Since the valve does not have a linear relationship between its opening and its ...
0
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0answers
24 views
Pneumatically operated three way valves
I basically need to replace these valves with a modern equivalent
It’s a pneumatically actuated three way valve for high pressure and flow rate (200 bar, 50 liters/minute). The liquid is basically ...
1
vote
1answer
45 views
Can air flow occur in both directions in a 2 way solenoid valve?
I'm designing a system where I need to fill and exhaust air from an an air bag. The air will be supplied from a dc motor. As of right now I've been considering placing a 2 way solenoid valve for air ...
4
votes
0answers
132 views
Part to pierce the valve on a 16g CO2 cartridge and connect to a Solenoid valve
The specific part that I’m after is something that can connect to a solenoid valve and a CO2 cartridge that will break the seal on the end of the CO2 cartridge.
The solenoid valve connection is ...
0
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0answers
47 views
Is there a valve design or system that can do this?
I am trying to come up with a way to bleed air from a tube to avoid air (gas) from reaching the other end of the tube. Is there a way to do this automatically? It must be able to work in all ...
0
votes
1answer
48 views
0 energy one way valves [closed]
Is there such thing as a check valve that takes no energy from water for water to pass through? What is the name of this/these check valve type/s? I barely know anything about engineering, just have ...
2
votes
2answers
18 views
Does it make sense to have a pressure and flow controller on a single closed line?
I have seen P&IDs in which a single line has both a pressure and flow control valve. Based on my understanding of Bernoulli's equation however this doesn't make sense to me - because ultimately ...
-1
votes
3answers
75 views
How can I keep my soda bottle at atmospheric pressure while dispensing the liquid via a sealed system pump?
I am making a "bar bot" and I am trying to figure out a way to dispense soda without it going flat. I am using a bunch of peristaltic pumps:
Which luckily remain sealed at rest. I was ...
4
votes
2answers
80 views
Divide Flow and Maintain Pressure
Im in the process of building an espresso machine from readily available parts. I have a solenoid pump that supplies pressurized hot water to the coffee grounds. I want to be able to tune the pressure ...
1
vote
0answers
38 views
maintenance of steady flow through pressure or mass flow
let's say I have two points in a line, A and B. Between them there is a valve that can regulate the amount of the stream from A to B. Considering that there is a steady flow of the stream between A ...
1
vote
3answers
172 views
Is there a type of check valve that allows gas to flow in both direction but stops liquid from flowing back?
I have a pressure regulator to maintain a specified pressure in a vessel that also contains a liquid. The regulator can pressurize or relieve pressure of the vessel. I want to prevent the liquid from ...
2
votes
1answer
43 views
How to periodically shut down a recirculating hot water solar thermal system
I am posed with a scenario where a hot water solar thermal system has been setup. The system comprises of a cold water tank, heating arrays and then a hot water tank. The system is closed loop and ...
0
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0answers
155 views
Using one electrical pump for multiple hoses
I'm currently trying to figure out a cheap way to build a cocktail machine.
For now the machine should have about 20-30 possible input liquids. These liquids should remain in their original bottle ...
1
vote
1answer
3k views
How to inflate or deflate a bouncy ball that lacks a standard valve?
I found this bouncy ball in my garage. It is too deflated to use and too inflated to store, so I would like to inflate it or deflate it. It doesn't have a standard valve for a bike pump: the only ...
0
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0answers
42 views
Equation to calculate flow rate
Assume you have a solid walled sphere with an opening of diameter x. The sphere has volume 0.02 litres and has air at 1.4 bars.
What general equation would be appropriate to correctly size the ...
2
votes
1answer
73 views
Help with simple hydraulic circuit to use for a four legged Robot
Firstly i am new to hydraulics, i want to build a hydraulic circuit that powers 4 cylinders at each leg of a Quad-Wheeled-Robot. The idea is to move the Chassis of the Robot up and down in all ...
1
vote
2answers
365 views
PC Controllable DC Power supply (0-30V)
I have a Proportional solenoid valve that uses a 0-30VDC for control (opening the orifice) I only have capability to provide 0-5V or 0-10V. I need to control the valve using my PC. Is there any DC ...
1
vote
1answer
83 views
How are the modern hydraulic cylinders very precisely controlled?
My guess is that they use brushless Motors that in turn powers the hydraulic pump.
But there must be some kind of valve that could help in the process. Still the burning question is just by adjusting ...
1
vote
0answers
19 views
Valve advice for chiller test rig
I am in the process of designing a chiller test rig, of which a very simplified diagram would be (the quick coupling might just be replaced by a non-return valve):
I am struggling to find the type of ...
1
vote
1answer
23 views
Create low velocity pressure drop?
I need to create a variable 3-7 psi / 0.2-0.5 bar in a low density gas running through some piping. I can calculate the required Cv factor to do this with a valve would be in the 30-200 range. Looking ...
0
votes
1answer
135 views
Liquid Rocket Plumbing and Instrumentation Diagram: Standards and Presentation
I'm working on a team to build a liquid sounding rocket as a school project. We need to present our plumbing and instrumentation diagram, but we are butting heads on what program and standards we ...
1
vote
1answer
42 views
Build Device for Emitting Weak Air Bursts at Specified Frequency
I'm a neuroscientist interested in building a device to replicate the following study.
https://www.nature.com/articles/s41598-018-24924-9
Essentially, they sent air through a nose catheter to ...
1
vote
0answers
24 views
Is this Proportional Electro-pneumatic valve a direct replacement for other valves listed?
In the midst of trying to redesign the pneumatic subsystem of a combined system, I'm at the point of validating a new valve would serve as a direct replacement. The reason for the redesign is an ...
1
vote
1answer
46 views
Is there a male and female valve that is closed until connected together?
I'm trying to make a quick release male and female connector similar to the one shown here.
One connector is attached to the bottom of a container filled with liquid. When it is not connected it is ...
1
vote
1answer
828 views
What is the point of this valve that only allows air in and not liquid?
I'm looking at googles mocktails maker. And it puts 2 holes in a container. 1 hole is connected to a pump that will take water out and the other connects to a backflow prevention valve that only ...
2
votes
0answers
52 views
Liquid phase gas flow through valve
I have been trying to figure out how to calculate the required dimensions for liquid phase gas through a solenoid valve. Many companies (Swagelok, Bürkert, Asco) provide "Flow coefficient calculators" ...
1
vote
1answer
241 views
Reduce 180 degree rotation to 90 degree rotation without gears
I am actuating a small ceramic rotary valve with a cheap mg996 servo motor. The valve has a 90 degree max rotation from fully closed to fully open. Currently I have the servo shaft directly coupled to ...
1
vote
1answer
248 views
Check valve with precise cracking pressure
I have two containers of air, one at 100 kPa and rising, the other at 30 kPa and decreasing. I need a valve that lets air through when the pressure difference is >70 kPa. Where would I find a valve ...
0
votes
1answer
240 views
Typical tolerances for valve lift using a camshaft?
I am working on a linear actuator for a valve.
Wondering if anyone out there can point me towards the tolerances that are used for valve lift in a typical internal combustion engine using a camshaft?...
1
vote
1answer
101 views
Why does the water pressure initially drop then stabilize when pressure testing a valve?
Sometimes the dropping goes on so long(10-15 minutes) that the test is thrown out and the valve is opened and filled with water for a longer period of time. Pressure testers claim that it is because ...
2
votes
2answers
176 views
Deflection of a stack of disks under applied force/pressure
I'm trying to calculate the deflection of a stack of metallic disks, when subjected to a force.
In the case of the figure below, representing a valve for a shock absorber, the force is due to a ...
0
votes
3answers
120 views
How to find the balance position of valve downstream a tank?
We have a tank which has a constant inflow of water (Qi). The level (h) of water in tank is controlled by opening/ closing (l) a valve downstream of the tank. Overflow height of the tank is 4 meter. I ...
1
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2answers
61 views
Can I make check valve in simple workshop?
I need a check valve ( one way valve ) for my project which has less actuation force (IDK real term. shouldn't require high pressure for inflow of fluid) and I searched in market for the valve but ...
0
votes
1answer
84 views
How to maintain a static negative pressure in a valve?
My target is to create a valve with multiple inlet capillaries. And my output is a pipe of a larger diameter. I do not want to use any electrical systems, and at the same time, I want to maintain ...
0
votes
1answer
31 views
where to find / what to call a 3/4 inch air valve that can be opened/closed electrically? [closed]
I'm looking for something like this air valve:
(as discussed in https://engineering.stackexchange.com/a/12404/12007)
But I need to tube to be wider (3/4 in), the tube to be shorter (the shorter the ...
0
votes
1answer
105 views
Automated valve for testing module
I work frequently with materials sensitive to oxygen and moisture, within a glove box. However, there are frequently times I want to move these samples from the glove box to a scanning electron ...
2
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0answers
537 views
Best types of valves for dirty services
I've just started to learn Gate, Globe, Ball, and Butterfly valves.
I'm thinking about "dirty services" now.
Which types of valves are most suitable for dirty services, and what characteristics ...
