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Questions tagged [valves]

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20 votes
1 answer
528 views

Sizing a pressure safety valve for two-phase flow

I understand that valves in two-phase vapour / liquid were sometimes sized by considering the required vapour and liquid flow rates separately, and then adding the results together. But this is now ...
SecondVector's user avatar
7 votes
1 answer
431 views

Is it possible to replicate a Tesla valve in large scale?

Supposedly a Tesla valve will impede fluid or air flow in one direction whilst allowing flow to move freely through the valve entering from the opposite direction, without using any moving parts. Also ...
James's user avatar
  • 121
5 votes
2 answers
221 views

For a small valve in a fluid system, what is the relationship between pressure and flow rate?

The specific example I have in mind is a car tire with a small leak in it. As the pressure increases, does the outflow of air increase linearly, i.e. $v\propto P$, or does it have some more ...
Chris Mueller's user avatar
5 votes
0 answers
398 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 ...
Oliver Nicholls's user avatar
4 votes
2 answers
121 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 ...
Brian Collins's user avatar
4 votes
4 answers
210 views

Which components to use for a CO2 gas storage?

I have a CO2 production for my aquariums (currently 2, but the solution should be extenable to - let's say - 5) based on fermentation of bio mass (CO2 is used as fertilizer there) which consist of a ...
Kalle Richter's user avatar
4 votes
2 answers
5k views

Solenoid valve pressure drop

I'm designing a solenoid valve for an automated irrigation project that I'm working on. After having looked at some designs, I have a question. For most of the designs I've seen, the orifice is ...
azhamn's user avatar
  • 55
4 votes
1 answer
39 views

Is there a (sort of inverse security) valve which opens if one connected side has a pressure below a certain value?

Security valves with two connectors open if the pressure exceed a value x +/- tolerance on one side. I'd like to know if there's a mechanical valve which opens if the pressure on one side sinks below ...
Kalle Richter's user avatar
4 votes
1 answer
18k views

LO/LC, CSO/CSC Valve Definition

Does any one here know of an authoritative source (ASME, ISA, NFPA, OSHA, etc..) that gives a definition for the following in one of their standards or codes and the number for that standard or code: ...
Jrican's user avatar
  • 150
3 votes
3 answers
399 views

Does this exist? -Sliding Fluid Restrictor -Solenoid Valve -Ball Valve

I am trying to come up with a way to restrict beer flow using a valve that does not cause foam. I have found that a solenoid valve causes a change in the direction the beer must flow and this sharp ...
Peace's user avatar
  • 33
3 votes
1 answer
615 views

What is this plumbing apparatus?

This device is about five feet tall. It is located in a ground-floor alcove in the exterior of a commercial building on a public street in Santa Monica, California. Each of the chained manual valve ...
Mark Dominus's user avatar
3 votes
2 answers
302 views

What type of liquid flow control could this device use?

I am trying to figure out what kind of device is being used to stop and start the flow of liquid inside this device. Below is a link to the device. It looks too small to be a solenoid or a pump. How ...
JoeTaylor's user avatar
3 votes
1 answer
267 views

Service Life of a Flashback Arrestor

First of all, I would like to know about the service life of a flashback arrestor. In my laboratory, I got three flashback arrestors {WITTgas RF53N(1/4”NPT-F), Brass} from the ex-students who used ...
Shubhra Kanti Das's user avatar
3 votes
1 answer
56 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 ...
NoumanQ's user avatar
  • 131
3 votes
1 answer
524 views

Automatic siphon above max height

The soil in my area has a very thick clay content (apparently left behind by glaciers, damn ice age). Because of this drainage in my yard is horrible. I've put in some underground drainage (french ...
TruthOf42's user avatar
  • 141
3 votes
1 answer
185 views

How to evaluate solenoid valve specifications

I need to replace a solenoid valve, and I need help in identifying the specifications that I should check for an equivalent replacement. This is a picture of the valve itself: Click for larger image ...
user avatar
3 votes
2 answers
477 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 ...
Micah Lindstrom's user avatar
2 votes
1 answer
45 views

Improving O-Ring/flapper valve injection mold ->non-engineer

I make specialized flapper valves that are similar to O-Rings. The current model uses aluminum sheets as base disks that adhere to the rubber (2 part urethane). The rubber is poured into the waxed ...
Lilly Whelan's user avatar
2 votes
2 answers
387 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 ...
André Almeida's user avatar
2 votes
1 answer
2k 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'...
benjarojas's user avatar
2 votes
2 answers
226 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 ...
user2250537's user avatar
2 votes
4 answers
1k views

Why to avoid low and high fluid velocities in hydraulic systems

I know that different geometries of piping, orifices etc... have different critical Reynolds values. If the value is exceeded laminar stream will turn to a turbulent form which causes a variety of ...
André Rodriguez's user avatar
2 votes
1 answer
59 views

What valve to use to divert incoming air from a pipe to another pipe stream?

There's an 4 inch exhaust stream that's emitting air at 2000CFM, I want to divide the exhaust in a 'Y' kind of outlet with two pipes. If State 0- Exhaust out through one pipe. If state 1- Exhaust ...
touchaddict's user avatar
2 votes
1 answer
2k views

How strict is the direction of air flow in a single direction pneumatic solenoid valve?

I am currently designing a small pneumatic system that pumps air into an airbag, holds the air in, then releases it to the atmosphere. Each pump in the system actually feeds two sets of airbags and ...
Beginner116412's user avatar
2 votes
1 answer
426 views

Fluid dynamics: valve and pressure drop

I have a question regarding valves: Let's assume a district heating system where you want to control the mass flow in a sub-station with a valve. Is (in normal cases) the diameter of the valve (fully ...
Kenni's user avatar
  • 71
2 votes
1 answer
2k views

Valve for mini CO2 gas canister?

I am in the process of helping my son design a sort of model of the Bloodhound SSC car for his school project, using balsa wood, model aircraft wheels, etc... It doesn't have to a like of like, but ...
am304's user avatar
  • 1,841
2 votes
1 answer
79 views

Device to remove condensate, without creating a hazard (EX) zone

I have gas pipeline with biogas, low pressure - approx 40mbar over atmosphere. I want to remove a small amount of condensate, inside a building, without creating an ex-zone. Small amount: I honestly ...
mart's user avatar
  • 4,791
2 votes
0 answers
88 views

What specific characteristic of proportional solenoid valves makes the flow to current behavior quadratic?

If experimental data is obtained from a proportional solenoid valve, specifically flow vs current (assuming inlet pressure is constant), the fit is nearly quadratic in nature. Andersen's Analysis and ...
docscience's user avatar
1 vote
3 answers
52 views

Volume multiplying hydraulic pressure reduction unit?

I'm tying to figure out what something is called, assuming it exists at all. If I knew what to search for, I'm reasonably sure I could figure out which part would be suitable for the application, but ...
BCS's user avatar
  • 179
1 vote
3 answers
876 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 ...
Paskoual's user avatar
1 vote
3 answers
9k views

Can PWM be used to control the flow of a solenoid valve?

Most cheap pump can achieve, according to the Amazon page, around 5 PSI and I would need something a way higher that can still be controlled. I have this solenoid valve. Can I use pulse-width ...
Dat Ha's user avatar
  • 219
1 vote
1 answer
7k 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 ...
emonigma's user avatar
  • 161
1 vote
1 answer
388 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 ...
Athena's user avatar
  • 11
1 vote
1 answer
48 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 ...
user2570937's user avatar
1 vote
2 answers
739 views

How much is too much control valve cycling?

In a textbook on process controls, I read that when tuning a controller there must be a balance between performance and excessive control element cycling. My question is, what corresponds excessive ...
Salomon Turgman's user avatar
1 vote
3 answers
2k views

Reverse float shutoff valve

I have an application that is drawing fluid from a reservoir via a standard dip tube. This application has a special requirement that once the fluid is depleted from the reservoir, the pump pulling ...
bgmaster's user avatar
  • 113
1 vote
2 answers
70 views

Is there anything close to automatic shuttle valve?

I am building a pneumatic system that needs an automatic shuttle valve. That means if I apply air pressure on one of the inputs In1, it closes the other input In2 and creates a path between In1 and ...
NHB's user avatar
  • 11
1 vote
2 answers
371 views

How does this transmission valve "hydraulic computer" work?

I just came across this: The claim is that it is a kind of analogue computer. But I don't see any moving parts. How does it work? EDIT: If someone could draw lines on the diagram to illustrate, that ...
spraff's user avatar
  • 131
1 vote
1 answer
2k 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 ...
J. Choi's user avatar
  • 121
1 vote
1 answer
95 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 ...
user200509's user avatar
1 vote
1 answer
97 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 ...
Sherlock Homies's user avatar
1 vote
1 answer
33 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 ...
ericksonla's user avatar
1 vote
1 answer
44 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 ...
asheff794's user avatar
1 vote
1 answer
2k 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 ...
user2570937's user avatar
1 vote
2 answers
102 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 ...
Ashesh Shrestha's user avatar
1 vote
2 answers
595 views

Water valve for over 120C temperature

I am making a project where i need to put a water valve below the tank and then need to open it automatically but the problem is that already available brass electric valves aren't good enough to ...
ZBT248's user avatar
  • 17
1 vote
1 answer
79 views

How can I build a electronically controlled valve for a 1/4 inch tube

I'm looking for a practical efficient way to open and close a 1/4 inch gravity fed hose. Initially I was thinking of using a Solenoid, but can't find anything suitable. My second thought was using a ...
user379468's user avatar
1 vote
2 answers
68 views

What would prevent me from using this valve for water?

https://www.kingstonvalves.com/product/ksv25cr-stainless-steel-asme-soft-seat-safety-valve/ Looking to use this for water instead of air. I haven't seen a good reason not to as the physics of the ...
Jirhska's user avatar
  • 111
1 vote
1 answer
64 views

Are there hydraulically actuated pneumatic valves?

I am working on a hydraulic system that is powered by an air-hydraulic piston pump, the pump uses pneumatic pressure to drive a piston which then pressurizes the hydraulic system. The system needs to ...
David's user avatar
  • 31
1 vote
0 answers
40 views

Understanding flow curves of an hydraulic directional proportional valve

In the picture below you can see the command signal to flow curves for a proportional valve I'm using. Since I'm using it to control the speed of a cylinder I was looking at the looped flow path ...
Landau's user avatar
  • 151