As with any product, it’s crucial to identify the type of valve, the manufacturer, inlet/outlet size, operating and maximum pressures, solution temperature, and the solution passing through the valve. It’s critical to know what solution is passing through the valve to ensure proper chemical compatibility. Knowing the solution’s PH level can also be another important factor when determining suitable components and materials.
How to choose a valve?
Before selecting your valve, you will need to determine. Will it be used to regulate a fluid or stop its flow?
It is necessary to verify the media that will circulate in the system is it a gas or a liquid? Is the media corrosive, chemically neutral, a food product or a medical fluid that requires special hygiene conditions?
When it comes to the operation system of the valve it is important to know whether it is powered manually or automatically. In one case, someone must be on-site to operate the valve, while in the other case the valves can be operated remotely, from a control station for example.
Finally, it is important to know how the valve will be integrated into the system and the type of assembly or installation used, especially if it needs to be welded, bolted through flanges or screwed in.
Once you have determined these different elements, you can focus on the technical characteristics of your installation, in particular the flow and pressure that will allow you to determine the dimensions of your valve.
How to calculate the dimensions of your valve?
- The pressureis an essential factor to take into account, on one hand so as not to undersize your valve and expose you to problems of leakage or rupture of the valve, and on the other hand to avoid over sizing it.
- You must identify the operating temperature, i.e. the temperature of the circulating media, as well as the ambient temperature around the valve body. It is important to know the extreme temperaturesthe valve will have to undergo in order to be able to choose a valve designed to operate under these conditions, in particular with regard to the materials used for the manufacture of the body, the closure system and the sealing parts.
- The operating pressure, i.e. the pressure the media circulates at in the valve.
- The fluid flow rate and the flow velocity. Flow rate and nominal speed are essential elements that will help you choose the appropriate valve, especially if it is to be used to regulate this flow rate. The flow factor (Kv) is a theoretical value defined by the manufacturer that allows the nominal flow rate of the valve to be calculated. It can be indicated in litres per minute (l/min) or in cubic meters per hour (m3/h). Valve manufacturers offer charts to determine this factor based on the desired flow rate and nominal diameter.
- The nominal diameter(DN) of the circuit where the valve is. This is vital to avoid over sizing the valve, which could lead to unstable operation of the installation, or under sizing it which could lead to a significant pressure drop and rapid damage to the valve.
What are the main types of valves?
The choice of a valve also depends on the flow rate, pressure and type of fluid transported because this will determine the materials the valve is made of.
In the butterfly valve world, it’s important to first determine which style of butterfly valve you possess. The two most common styles are Wafer or Lug bodies. A wafer-style butterfly valve has “thru” bolt holes that run along through the outside rim of both pipe flanges. In contrast, a lug-style butterfly valve has threaded bolt holes on both sides of the valve body to allow for “end of line” applications. Lug-style butterfly valves are, generally, less common than wafer-style butterfly valves. Below, you will see a wafer-style valve on the left and a lug style valve on the right
Butterfly Valve Actuators
Next, we get into the topic of valve actuation. We primarily stock butterfly valves that are manually (seen above with handle) or pneumatically actuated with either double acting or spring return actuators. A double acting butterfly valve actuator requires air pressure to open the valve and then air pressure to close the valve.
A spring return butterfly actuator is used in fail-safe applications. If there is a loss of air pressure the valve will automatically close (or open) – due to the spring tension of the actuator. Spring return actuators are used in many production plants that require system flow to cease once power is cut or lost – as mentioned above, this is a fail-safe application example.
Electric Actuators are also used in many industries. While we don’t stock electric actuators for butterfly valves – we have access to them. Actuators can also be provided with “positioners”, limit switches and other controls.
A ball valve is probably the most common type of valve that exists – across all industries. It gets its name due to the fact that it actually has an internal ball that sits in a “seat”. When the handle or knob is turned 90 degrees from the inlet/outlet ports, the valve is closed and one can see the convex shape of the internal ball. When the handle is turned parallel with the inlet/outlet ports, the valve is open and one can view through it – unhindered.
On the left, below, is an example of an air actuated, stainless steel, female pipe thread, ball valve. While on the right, you will see a Banjo, polypropylene, manual, flanged, ball valve.
By design, ball valves that are listed as Standard Port actually have less fluid path than the inlet/outlet ports size limitations – this is somewhat misleading to those that are unfamiliar with the concept of Standard vs. Full Port valves.
For example, if you have a 2 inch Standard Port valve your flow characteristics will be closer to that of a 1.5-inch fluid path. The technical reasoning behind this is the fact that a smaller opening creates more friction loss (i.e. pressure drop) thus resulting in a decreased flow rate. Standard port ball valves are cheaper than full port valves but restrict the system flow rates; somewhat. So, if flow rates don’t matter or affect your system then you can save money up front by selecting standard port valve(s) for your plumbing system.
Full port valves allow the plumbing system to realize the full flow characteristics of the valving. If all valves in a system are two inch full port, valves then we can reasonably assume increased flow rates in comparison to a system that contains all standard port valving. A full port valve has a slight design change that allows for this increase in flow characteristics. While the valves may look the same externally, there are internal design changes that are not visible to the naked eye.
High Pressure vs. Low Pressure
This is another crucial step in determining the correct valve for a specific application. If necessary, place a pressure gauge at various points in the plumbing system to determine the system operating pressure. Never guess the operating pressure of a system. If a low pressure valve is installed into a high pressure system, serious or fatal injury could occur. As a general rule of thumb, anything below 150 psi is considered Low Pressure – that being said, there are valves rate for pressure less than 150 psi.
This gets back to one of our core fundamentals when selecting a proper valve – determine operating pressure and maximum pressure for the intended plumbing system.
Ball valves are a perfect example of how the same style valve can be used in multiple applications – both high pressure and low pressure. We have some ball valve product lines that have use applications which are limited to certain industries – due to their operating/working pressure limitations. However, we have many ball valve lines that carry over into multiple industry applications.
While we do carry many products that can be cross-utilized in various industries we always want the customer to confirm an operating pressure. This ensures safety in application and use. Furthermore, it minimizes the possibility of injury and lessens the chance of damage to the valve and other plumbing system components.
Air Actuated & Electric Motor Driven
We carry ball valves that can be remotely operated via automation, as well. The most common types are pneumatic (air-operated) and electric motor-operated ball valves. Air operated are most widely used in chemical facilities, fertilizer plants, or industrial plants. Electric ball valves are most commonly used in agricultural applications for spraying applications. The trade name electric ball valve or pneumatic ball valve simply refers to how the valve is actuated.
When you drive down the road and see a large self-propelled sprayer, spraying in a field, you can be certain the booms are being remotely controlled. The boom valves are remotely controlled from the sprayer cab, with the help of electric ball valves. The sprayer operator sends a signal from his, in-cab, boom controller to turn certain sections of the sprayer boom on/off – based upon the field’s specific application requirements.
We also see electric ball valves in the turf industry. Golf courses or residential sprayers will commonly use this type of ball valve on their sprayer setups. It is more prevalent in the turf industry due to the fact that the booms are much smaller than the agricultural industry.
Lastly, we do a fair amount of business in the liquid deicing industry. If you have ever seen a department of roads/transportation vehicle that is applying liquid before a winter storm – you have witnessed this industry in action. These vehicles are applying a solution called liquid salt brine (sodium chloride, magnesium or calcium chloride solution). Electric driven ball valves are common in this industry because pneumatic valve airlines would freeze in the frigid winter temperatures.
For those interested, here is a link that further explains the process of creating the salt brine solution. Below is a picture of a pneumatic-operated ball valve, on the left. On the right you will see an electric-operated ball valve.
A flanged gate valve is used in larger flow applications. In the Dultmeier world, we most commonly see this style of valve used on large bulk fertilizer, fuel tank storage applications, and float storage tanks in the vehicle and fleet washing industry. Gate Valves are generally designed with a circular handle that is turned clockwise to close the valve and counter-clockwise to open the valve.
Just as any other valve, we need to confirm the solution that will be passing through the valve to ensure chemical compatibility and then confirm the working or operating pressures that are required by the plumbing system. Most commonly, we are supplying flanged gate valves for lower pressure ranges. Below is a picture of a common flanged gate valve used in the bulk fertilizer industry.
Globe & Angle Valves
A globe valve is very similar, from an external view, to that of a gate valve. However, when we look at the valves internally, they are quite different. As can be seen from the previous section, the gate valve operates almost like a wedge or slate that constricts or completely closes off flow. A globe valve has a different seat structure and more of a plunger that constricts or completely closes off flow.
Next up we will take a look into needle valves and the various applications they can be used for. Most commonly, we see these valves used in higher pressure applications such as car/truck wash and high-pressure cleaning. Here is a grouping of various needle valves on our website, to further illustrate the variety of options. That being said we do sell a fair amount of needle valves in the Anhydrous Ammonia industry for a bleed off application.
As always, in any application we want to confirm the solution passing through the valve, working or operating pressure range, and temperature of the solution.
We carry a wide supply of solenoid valves from a number of suppliers. A solenoid valve is another example of an electric valve. However, they are drastically different than electric ball valves. That being said, solenoid valves can be controlled remotely and are used in a number of industries.
We most commonly use them in high-pressure vehicle or fleet washing applications, industrial applications, and agriculture or turf spraying applications. Some users in the agriculture industry are starting to migrate away from solenoid valves to ball valves – the primary reason being the necessity for the ruggedness of a ball valve versus over a solenoid valve. Mother Nature in combination with aggressive chemicals is an extremely harsh environment for a valve.
Normally Closed vs. Normally Open
This is an important topic to address – especially in the realm of solenoid valves. If a valve is “normally closed” it means that the valve is closed in its uncharged state. More simply put, if there is no electrical current passing through the valve coil then it will remain closed. If a valve is “normally open”, that means the valve is open in its uncharged state.
Various applications will call for either style. Coils in these valves can be 12 volt, 24 volt, 110 volt and even 240 volt, which allows for a wide and versatile range of applications.
For example, in the vehicle washing industry, we may want to have a weep application on a spray gun. We would do this to ensure the gun doesn’t freeze shut in lower temperatures. Therefore, we want ambient water to continuously run through the system or spray gun – if a loss of power occurs. So, in this instance we would want to ensure a normally open valve be installed in this type of a plumbing system.
Next up, we will look into the world of check valves. This product is used to prevent backflow of a solution in a plumbing system. For instance, a check valve would be utilized when pumping a solution up a vertical pipe and you do not want the solution to backflow, due to gravity, when the pump is turned off. A check valve is a form of backflow prevention.
Furthermore, check valves keep a plumbing system charged. By keeping the system charged we can ensure more efficient delivery of product and reduce the number of air pockets that are present in the plumbing system, which reduces pump priming time and other potential pump problems. The more efficient a plumbing system is – the less it costs to keep it running.
A regulating valve can technically be any valve. In this sense, if you can constrict or control the flow by manipulating the opening threshold of the valve – you have just regulated the system flow.
To that note, we are going to look at this section with this one caveat in mind – a regulating valve needs to be remotely controlled. To do this, let’s first look into electric motor driven valves.
There are certain types actuators of ball valves or butterfly valves that manipulate the flow rate of the solution by opening or closing the valve stem a to a certain degree. Without getting too technical this is done in conjunction with some type of flow monitor that is able to communicate with the valve actuator through a control mechanism.
This control mechanism can be a simple rate controller in a sprayer cab or as complex as a computer dashboard in a chemical production facility. The regulating valve communicates to the flow monitor through the system controller to reach and/or maintain the desired flow rate. This controller can be a simple rate controller or a complex computer system.
Regardless of the application – in order to remotely control a regulating valve we must have a controller that sends a signal to the valve based upon the desired flow rate of the operator.
As always, any application we want to confirm the solution passing through the valve, operating pressure range, and temperature of the solution.
A diverter valve functions very similarly to a remotely controlled regulating valve. The main difference between a regulating valve and a diverter valve lies within the functionality. A diverter valve is designed only to guide product flow through a system. Therefore, the most common example of this would be a three-way ball valve.
We look at this section with the same caveat in mind – a regulating valve needs to be remotely controlled. To do this, let’s first look into electric motor driven valves.
The diverter valve would be remotely controlled through a similar mechanism as a regulating valve. The main difference is that the diverter valve “diverts” flow down fluid path A versus fluid path B – based upon the desired location sent by the controller or computer.
Foot Valves are commonly used in transfer systems that require the pump to maintain it prime. A foot valve is essentially a type of check valve. Foot valves are placed at the beginning of a suction line and are generally designed with some type of a strainer or screen to protect the plumbing system from sucking in foreign objects.
If you recall the design of the check valve, you will remember that a check valve closes when there is backflow pressure applied on the spring check. This forces the valve to close and keeps the system suction line primed, with liquid – thus increasing the overall efficiency of the plumbing system.
Relief & Unloaded Valves
Relief and unloaded valves are commonly used in higher pressure situations with positive displacement pumps. These valves are used to protect system components from dead-head scenarios. A positive displacement pump will continue forcing product downstream in a plumbing system until there is a system failure such as a burst pipe, fitting, hose, etc. Thus, the term: dead head scenario. To help combat this scenario, relief and unloaded valves were designed.
Back Flow Preventers
In any wash down application where an operation has a water supply line connected to a public water source then it’s absolutely necessary, by regulation, to have a back flow prevention valve in place. We distribute for Watts and commonly sell these units in vehicle/fleet wash applications, industrial applications and fertilizer/chemical facility applications. A backflow prevention system products the main water supply in the scenario where a local business would have a system failure and back up chemical, fertilizer, hazardous material, etc. into the main water supply – backflow prevention systems inhibit this scenario from taking place.
The shut-off valve is a closed-circuit valve that uses the valve flap to move along the centre line of the valve seat (valve) passage to control the opening and closing of the pipeline. The shut-off valve is generally suitable for transporting liquid and gaseous media within the specified standard range under various pressures and various temperature conditions, but it is not suitable for liquid containing solid precipitated or precipitated crystals. In the low-pressure pipeline, the shutoff valve can also be used to regulate the flow of media. However, due to structural constraints, the nominal diameter of the shut-off valve is below 250mm. If the pressure is high on the pipeline and the flow rate is high, the sealing surface will wear quickly. Therefore, when regulating the flow rate, a throttle valve is still preferred.
1. The wear of the sealing surface is not large, so the work is more reliable and the service life is long.
2. The sealing surface area is small and the structure is relatively simple. The time required for manufacturing the sealing surface and the precious materials required for the sealing ring are less than those of the gate valve.
3. It is more laborious to open and close the opening and closing torque. When closed, the direction of motion of the valve flap is opposite to the direction of motion of the medium, so the opening and closing torque is large.
4. The flow resistance is large. The flow resistance of the shut-off valve is the largest among all types of block valves.
5. The medium flow direction is unidirectional.
The throttle valve regulates the flow and pressure of the line medium by changing the cross-sectional area of the valve passage. The smaller the cross-sectional area, the greater the resistance to the medium being crossed and the smaller the flow. The throttle valve not be used as a shut-off valve because it generally does not have a sealing surface. Even it does have a sealing surface, the sealing surface is quickly eroded and loses its sealing property under the action of a high-speed medium.
The safety valve is a protection valve. It is installed on pressurized equipment, vessels, and piping. The safety valve is normally closed by an external force. When the pressure of the protected pipeline medium exceeds the specified value, the valve flap automatically opens to discharge excess medium to lower the pressure; and when the medium pressure returns to within the specified value, it automatically closes. The safety valve acts as a conduit to ensure safe operation of the system and equipment. Safety valves are widely used in boilers, compressor air reservoirs, high-pressure vessels and pipelines, etc., where the working pressure of the medium may exceed the allowable value and cause a risk of bursting.
Pressure relief valve
This valve can reduce the pressure of the medium in the equipment container or in the pipeline to a prescribed pressure. It can maintain the outlet pressure within a certain range in the case where the inlet pressure changes and the flow outlet changes.
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