Four Main functions of valves , Names, category and types.

Four Main functions of valves, Names, category, and types onboard ship valves are widely used for various purposes.

On-board ship valves are widely used for various purposes. These valves are mostly designed in such a way that it saver it functions as listed below: functions of valves.

Types of valves

There are several types of valves use the onboard ship and onshore, they are listed as follows;

  • Piston valves
  • Globe valves
  • Needle valves
  • Control valves
  • Diaphragm valves
  • Butterfly valves
  • Pinch valves
  • Gate valves
  • Ball valves
  • Knife gate valves
  • Check valves
  • Hydraulic butterfly valve

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Furthermore, the above-listed types of valves are equally classified into categories. Below, we are going to discuss more on the categories and point to the proper valve suitable for the function. Its well recommended that valves are used according to it function to avoid back pressure to the pump, not performing, flooding, etc.

Valves functions are categorized into four main parts.

1. Regulation
2. Isolation
3. specialized purpose
4. Non-Return

Following the above listed, these functions help you to categorize there types by names. below are the categories of valves, following its functions;

1. Regulation: valves which can be found in this category of functions are:

• Piston valves
• Globe valves
• Needle valves
• Control valves
• diaphragm valves
• Butterfly valves
• Pinch valves
2. Isolation: as the name sounds, the valves that can be found in this category of functions are :
• Piston valves
• Gate valves
• Ball valves
• diaphragm valves
• Plug Valves
• Butterfly valves
• Pinch valves
3. Specialized purpose: valves which can be found on this category of functions are:
• Float Valves
• Knife gate valves
• Line blind valves
• Multi-port valves
• Flush bottom valves
• Foot valves

4. Non-Return: This is commonly used where flows are not allowed return back after passage and valve which can be found on this category of functions are:
• Check valves.

How to overhaul valves?

Marine Valves are recommended to be overhauled at regular intervals. This is because if a valve is always in contact with sea water, with time, the seat, spindle, and other parts will lose it original state. Crating leaks and hard openings.

Some valves are sealed with O-rings on the spindle end, while some are sealed with gland packing. The gland packing or O-ring can be renewed if the valve got leaked.

To overhaul valve,

firstly, stop the pump and close any fluid link to the valve area. Remove the valve from the connected line or open the top side. There you can have access to the seat, valve flap, and other valve parts

Once you are done with the opening, carefully lap the seat surface and maintain a smooth surface for proper sealing. Renew the gland packing, clean the surfaces, change joint gasket if required and pressure test the valve.

To pressure test the valve, you need to close the valve, connect water or air with a required pressure to the inflow side. Then check for a leak; if the valve seat is not holding, you will see water or air crossing over.

We hope you are clearly understood the functions, names and which category each valve you may found onboard ships are. Also, hope you can easy overhaul your valve without any problem. but for any assistance, kindly contact us for a free consultation

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