Many people think that selecting valves for handling dry material is a relatively simple process. Many people believe that the only information you need is:
- Size of the opening
- Shape of the opening
- Available stack-up height
- Matching connections or hole patterns
But in reality, we need more information to accurately select the right valve for the application. Lion Bulk Handling is cooperating with a couple qualified valve manufactures and suppliers, to select the most efficient valve for that particular system and the required technical specifications of our clients. Costly mistakes can be avoided, if more information about the application parameters is supplied to us nd our valve partners. For example do you like purchasing an expensive valve for a simple application, or buying an inexpensive valve that cannot handle the technical conditions. Lion Bulk Handling and especially our valve partners have the experience and knowledge to know what valves and valve modifications do apply for certain applications parameters. It is therefore very important for us to receive all the parameters of the requested dry bulk handling solution.
So let’s begin with the premise that each application for each valve has its own unique requirements. What are the factors that determine what type of valve is selected and what modifications are necessary? Within this blog we are going to describe how you can select the correct valve, actuator, features, which modifications are possible and what kind of locations.
The Installation specifications determines which valve is suitable for that appropriate. The most critical question is “what is the valve intended to do?”. Is a gate valve, diverter valve, pinch valve or a butterfly valve needed to best fulfill the application? After this question is answered, you can follow up with the following questions;
- What is the opening or orifice size?
- Is the opening square or round?
- Will the valve be used in a vacuum, pressure or gravity application for conveying the dry material? If pressure or vacuum, how much?
- Will the valve be installed indoors or outside?
- Will the valve be installed onshore or offshore?
- What is the temperature of the air and material conveyed?
- Does the system use dilute phase or dense phase?
- What is the size of the conveying line?
- Are the lines tube or pipe?
- Does the valve need to be constructed of carbon steel, stainless steel, or aluminum?
- Will the valve be subject to wash-downs? If so, will it be washed with hot water or a caustic liquid?
- Will there be fluidization, aeration or vibration for flow control, if the valve is mounted below a bin/silo?
- What is the sequence of operations for the system, e.g., When will the flow control equipment be activated in relation to the cycle of the valve?
- If the is designed for gravity and is mounted below a bin/silo, then how is the material conveyed into the bin/silo?
Then you need to consider the material characteristics.
- What is the material to be conveyed?
- Is the material in powder, granular, or pellet form?
- What is the particle size of the material?
- What is the weight of the material per cubic meter/foot?
- Is the material sticky, abrasive, or corrosive?
- Is there spoilage or sanitary issues with the material?
- Will different types of material be conveyed through the same line? If so, are there cross contamination concerns?
There are many types of actuators to operate the valve to open and close. Depending on system requirements and power availability, actuators can be automated or manual. Automatic actuators are available such as air cylinder, air cylinder with magnetic piston, electric actuator, explosion-proof electric actuator, and hydraulic actuator. Manual actuators available are hand wheel, hand lever, and chain wheel actuators. To define which one is needed for your application, the following questions need to be answered:
- What is the cycle frequency?
- Will the valve close on material? If so, will the material be standing or moving column?
- Is compressed air available?
- Does actuation speed matter?
- What are the cost variables for replacement and repair?
- Can I use manual actuation when the valve is only for maintenance purposes?
- Is manual over right or manual actuator required on top of the automated actuator?
- Will the valve be outside in warm or cold temperatures?
Determine if the company that is manufacturing your valve offers standard modifications to suit application/material specific requirements. Lion Bulk Handling will ofcourse make sure that we select the correct valve for your bulk handling system. Some application specific factors that would need to be considered for valve modifications are:
- Duty Cycle
- Abrasive Duty
- Chemical Compatibility
- Particle Size
- Food Specific
- Indoor/Outdoor Service
Some valve modifications that can serve these challenges in the bulk material handling industry are Stainless Steel Material Contact, Water Wash Down, High Temperature Service, Cold Temperature Service, Modified Pipe Flange Mounting, US Dairy Standard, Coated Air Cylinder, Polished Gate Internals, Flexible Hose, Schedule Pipe Size, Clear Bonnet Covers, Straight Leg, Fabric Sleeve, Optional Bolt Hole Pattern, Sealed Body, Stainless Steel Rollers, Tube Offset Flange, Seal Access/Removable Seals, Abrasion Resistant Blade, Clean In Place, Round & Square Transitions, 30 Degree Offset, Dead Pocket, and Internal Diverter Linings, just to name a few.
VALVE LOCATION & ORIENTATION
Designate where the valve is to be installed and the orientation of the valve. The position of a slide gate or diverter valve in a system helps determine which accessories may be required for your application. For example, if a slide gate is to be mounted below a hopper, positioning controls may be required to measure material into the weigh hopper.
There are a number of different features available when selecting a valve. Each manufacturer will have their own standard products. It is therefore wise to contact the original valve manufacture for advice, repairs or replacement. Lion Bulk Handling has been dealing with several valve manufactures and suppliers in the past 50 years and can assist you with all your questions and spare parts request.
The following valve features are possible;
Abrasion Resistant Liners – Abrasion resistant liners positioned at the inlet of the gate address potential wear issues that may exist from either the volume or the abrasiveness of the material being handled. The liners are replaceable when needed.
Abrasion Resistant Blade -The gate’s blade can also manufactured of abrasion resistant steel. The combination of the abrasion resistant blade and liners are important in providing a gate that offers longevity and an exceptional life-cycle cost.
Adjustable Rollers – Externally greased hardened steel adjustable rollers are used to keep the blade dust tight.
Available Sizes – Valve standard sizes will be dependent on the valve and the manufacturer. Contact your manufacturer for available sizes.
Bonnet Purge – The optional bonnet purge is utilized to keep material out of the body of the valve and in the material stream.
Displacement End Pocket – A displacement pocket displaces the material at the leading edge of the blade as the blade closes. Rather than the blade jamming and packing this material into an end seal, the blade stops part way into the pocket. Material falls away from the blade and re-enters the material flow stream area. This feature can increase the valve’s service-life and reduce downtime costs related to maintaining and replacing end seals.
Optional Configurations – Available in straight leg and wye line configurations.
Replaceable Seals – Seals reduce interior valve dusting and can be replaced while the valve is inline.
Return Pan – A return pan can be added to seal fine material internally or to atmosphere. With this feature, material that enters the bonnet of the valve is returned to the material flow stream, thus reducing material leakage to atmosphere.
Wear Compensating Seals – Pressure loaded, polymer bonnet seals offer a dual purpose. They act as a wiper for material that may be on the blade as the blade retracts. They also seal material from entering the bonnet area of the gate. The “live load” on the back of the seal strip continues to apply pressure to the seal even as it wears. At a certain wear point, seals may be accessed and replaced from the outside of the gate, while the gate remains inline.
Wear Reducing Material Deflectors – Material deflectors are placed around the inlet of the valve and protect it from the material flow stream. By deflecting material away from the hardened steel rollers and blade seals, this feature significantly reduces wear and downtime keeping the valve in service longer.
Wear Resistant Bucket Design – A wear resistant bucket constructed from durable abrasion resistant steel and an optional ceramic liner can be added to reduce potential wear to the bucket. For even more durability, the additional of an optional honeycomb liner allows material to abrade on itself instead of the bucket.
Is there a specific request in regards to valves in general or do you have a specific application, please do not hesitate to contact Lion Bulk Handling via, http://www.lionbulkhandling.com/contact/ and tell us your project.
A lot of questions come in to play to select the right valve for your application. But, if you are prepared with the needed information for the valve manufacturer, you can be confident that you have purchased the solution that you need. If your manufacturer doesn’t ask specific detailed questions, you might end up paying too much for a simple valve that doesn’t meet your requirements, and you’ll end up wasting factory time and money to modify the valve for your application.
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