How Much Does a Slide Gate Valve Cost for a Pneumatic Conveying System?
There are several key factors that influence the price of a slide gate when utilized in a pneumatic conveying system. Here are five that definitely need to be taken into consideration:
1. Material characteristics
2. Contact surface
3. Operating environment
4. Actuation method
5. Electrical classification
Five Factors That Influence Slide Gate Valve Cost
When considering these factors, a deeper assessment of the specific application of the slide gate valve is necessary to get a better idea of cost. Some of the factors will lead to a more expensive slide gate while others won’t have much effect.
1. Material Characteristics. A critical part of a slide gate cost assessment is identifying the characteristics of the material being conveyed. Is the material a powder versus granular or a pellet? Is it sticky, corrosive or abrasive? The latter will require modifications to a slide gate to ensure a good seal. Modifications that are required due to the material conveyed will generally lead to increased costs.
2. Contact Surface. The next important consideration is the type of material contact surface the specific application requires. Contact surfaces can range from carbon steel to aluminum to 304 or 316 stainless steel. Material compatibility and abrasiveness will typically dictate the metal requirements for the contact surfaces of the slide gate. As higher grades of material contact are needed, the cost of the slide gate valve can increase substantially.
3. Operating Environment. Another factor contributing to slide gate costs is the operating environment (indoor versus outdoor service). Outdoor temperatures can fluctuate from very hot to very cold depending on geographic location. Although inside temperatures tend to remain more constant, they can still play a role in the type of slide gate valve needed. Choosing the appropriate seal material will impact cost significantly because of wear life, melting point, corrosion and potential swelling of the seal. Sometimes, finding a seal material that meets all of these criteria can significantly drive the cost of the slide gate valve up.
4. Actuation Method. The actuation method used for a slide gate valve can also affect costs. There are four primary actuation methods typically used in conveying systems:
Manual actuation means you are utilizing a hand wheel, hand crank or chain wheel to actuate the valve open or closed. These would typically be used in low actuation applications or to perform system maintenance. Manual actuation will help to reduce slide gate costs.
Pneumatic actuators are typically used for slide gates designed as process valves. These are good for high cycle rates and when closing through a standing column of material is required. Pneumatic actuators require the availability of plant air to be plumbed to the valve. The pneumatic actuators alone will not affect price much in either direction.
Hydraulic actuators are also utilized for applications that require you to cut through a column of material. They offer higher amounts of force to help the slide gate push through the material. They also require a hydraulic system with a line plumbed to the actuator for the slide gate valve to operate. Using this type of actuator will typically add to the overall cost of a slide gate.
Electric actuators can also be utilized on a process valve. They typically only have a 25% duty cycle so they cannot be used in high cycle applications. They are utilized extensively in cold outdoor environments because they are not susceptible to freezing. Electric actuators only require electricity so they are basically a self-sustaining actuator. Like hydraulic actuators, the cost of the slide gate will increase.
5. Electrical Classification. This is another consideration when using non-manual actuated valves. Any pneumatic, hydraulic or electrically actuated valve controls will fall under a specific NEMA (National Electrical Manufacturers Association) classification. For instance, electrical controls with NEMA 4 requirements are considered water/dust tight whether indoors or outdoors in typical environments. While electrical controls with NEMA 7/9 requirements are designed for hazardous locations (combination of class I fumes/ vapors and class II dust). The cost between these types of electrical components can be sizeable and have a major influence in the overall cost of a slide gate valve.
Clearly Specifying a Slide Gate Valve’s Application Up Front Saves Money
In summary, the more information that can be provided about the slide gate valve’s application initially, the more control the customer will have over the price of the valve. If the supplier has all the details, they will not need to add unnecessary modifications that could increase the cost of the slide gate valve.