Valve hammer edition

Use this online Water Hammer Calculator to find the Pressure increase in water hammer. Water hammer (fluid hammer) is a pressure surge or wave that occurs when the fluid flowing in a particular direction is forced to stop or change direction. The below water hammer calculator helps you calculate Pressure Increase (P), Flow Velocity (V), Upstream Pipe Length (L), Valve Closing Time (t) and Inlet Pressure (Pi) alternatively with the other known values. Use this online Water Hammer Calculator to find the Pressure increase in water hammer. Water hammer (fluid hammer) is a pressure surge or wave that occurs when the fluid flowing in a particular direction is forced to stop or change direction. The below water hammer calculator helps you calculate Pressure Increase (P), Flow Velocity (V), Upstream Pipe Length (L), Valve Closing Time (t) and Inlet Pressure (Pi) alternatively with the other known values. Code to add this calci to your website Formula:P = ((0.07 × V × L) / t) + Pi V = ((Pi - P) × t)/(0.07 × L)L = ((Pi - P) × t) / (0.07 × V)t = ((0.07 × V × L) / (P - Pi)Pi = P - ((0.07 × V × L) / t)Where, P = Pressure Increase V = Flow Velocity L = Upstream Pipe Length t = Valve Closing Time Pi = Inlet Pressure Example: Water Hammer Calculation for Pressure IncreaseFind the pressure increase in water hammer if the flow velocity, upstream pipe length, valve closing time and inlet pressure values are 23 ft/s, 10 ft, 5 s and 7 pound / inch2.Solution: P = ((0.07 × 23 × 10) / 5) + 7 = 10.22 pound / inch2 (adsbygoogle = window.adsbygoogle || []).push({});

Have a water supply that is controlled by solenoid valves. These are electrically operated and they stop the flow of water immediately. When this happens, the water reflects back up the pipe and creates a shock wave that causes the bang.Worn Stop ValvesThe hammering may also be caused by worn stop valves. Stop valves can cause water hammer if they have loose gland packing and/or worn washers. The valves will generally be open when the water hammer shock wave travels through the pipework and the shockwave could well 'rattle' the valve handle and a loose jumper.Clogged Air ChambersIf you’ve never had water hammer and one day you suddenly experience it out of the blue, then it’s likely your water system’s air chambers are blocked. These chambers often become blocked with water or residue from minerals found in water. The blockage will stop the chamber from absorbing the pressure in your system and, as a result, you will hear an occasional bang.Water Ripples from the TankAnother cause of hammering pipes is water ripples created by a float valve inside your water tank. When water flows into the tank, the valve float rocks up and down, constantly closing and opening the valve. This creates a “wave system” that echoes along the pipes, causing the hammering sound. Plastic water tanks can flex considerably, so they should have a reinforcing plate (metal) to stop them moving.Fast-acting valvesA common cause of water hammer can be fast-acting valves on appliances such as washing machines or dishwashers. These valves suddenly stop the water that is moving along the pipes. A shockwave results and this causes the pipes to shudder, causing the banging. The banging gets worse as the valves are worn.How to Stop Water HammerWater hammer isn’t just irritating - it can also go on to damage

Different components of your plumbing and pumping systems. That’s why it’s important to get rid of water hammer as soon as possible. A loose pipe or worn stop value could end up costing you thousands of pounds.Secure Any Loose PipesIf loose pipes are turning mild shock waves into loud bangs, you can prevent it by securing pipe straps, adding new pipe straps or tightening studs or joists.Remember, do not mix different metals when securing pipes. A steel strap should not be used to secure a copper pipe or vice versa. Different metals can chemically react and cause corrosion of the metal.If the problem pipes are located in hidden areas, then you will more than likely need a plumber to come out and help you find the issue.Wrap Pipes in Foam InsulationAnother idea is to wrap pipes in foam insulation. The foam should help prevent banging by absorbing the shock waves. This can also help prevent pipes from freezing in the winter. Make sure to leave space for expansion around the pipe.Fix Washing Machines or DishwashersIf the banging only occurs when using the washing machine or dishwasher, then the problem is likely the solenoid valve. The solenoid valve is a component of your machine used to shut off the water supply. If the response time of the solenoid valve is too quick, then the fluid inside the valve is abruptly stopped. In this case, the fluid reflects like a wave causing a shock wave back up the pipe that you hear as a bang. The simple fix is to choose a solenoid valve or other valve type that has a slower response time.Install a Water-Pressure RegulatorA common cause of water hammer is high water pressure. If your pressure is running near 100 psi, then it’s likely the cause of your issue.

The magnitude of the water hammer depends onFluid propertiesVelocity of flowModulus of Elasticity of the pipe materialLength of the pipe lineSpeed in which the momentum of the fluid changesThe low modulus of elasticity of fiberglass contributes to a self dampening effect as the pressure wave travels through the piping system. The magnitude of pressure wave in a metallic piping system is much higher due to the higher modulus of elasticity of these materials. In addition to rapid valve closure or opening, sudden air release and pump start up or shut down can create water hammer. Talbot formula gives:where,a = Wave velocity (ft/s)P = Surge Pressure (psi)v = Change in flow velocity (ft/s)w = Density of fluid (lb/ft3)SG = Specific gravity of fluidK = Bulk modulus of fluid (psi)E = Hoop modulus of elasticity (psi)d = Inside diameter of pipe (inch)t = Pipe wall thickness (inch)g = Acceleration due to gravity (ft/s2)Good design practice usually prevents water hammer in most systems. Installation of valves which cannot open or close rapidly is one simple precaution. In addition, pumps should never be started into empty discharge lines unless slow opening mechanically actuated valves can increase the flow rate gradually. Check valves on pumps should close as quickly as possible to minimize the velocity of fluid flowing back. In some cases, thoroughly anchoring the piping system may mitigate this problem. In other cases, mechanical valve operators, accumulators, or feedback loops around pumps may have to be used to remove the source of water hammer.