Advantages and Disadvantages Of The Use Of Valves

Advantages of Gate Valves

  1. Sealing properties are very good.
  2. These valves can be used in two directions in the system.
  3. They provide smooth flow, pressure loss is at minimum level.

Disadvantages of Gate Valves

  1. They cannot be opened and closed quickly. For full opening and closing with handheel or gearbox, the stem must be rotated by the number of full opening turns. The number of full opening or closing turns is up to the nominal diameter / pitch.
  2. Requires a large space for installation, commissioning and maintenance.
  3. The slow movement of the slide in the fully closed position causes a high flow rate. This leads to wear and deformation of the site surfaces due to vibration and impact, and the contacting surfaces are damaged.
  4. In systems where high temperature changes irregularly, it causes leakage in gate valves due to the pipe load at the end of the valve.
  5. Repair and maintenance of the seat surfaces at the place of use is difficult.

Advantages of Globe Valves

  1. Full closure properties are good.
  2. Throttling properties are good.
  3. Compared to gate valves, the stroke and therefore the opening-closing time is shorter.
  4. Body ring seating surface treatment is easier.
  5. They can also be used as stop-check valves with a small precaution to be taken at the stem and disc connection.

Disadvantages of Globe Valves

  1. Pressure loss is high compared with gate valves.
  2. It needs an actuator with a larger force or larger torque to close under high pressure.

Advantages of Ball Valves

  1. Provides leak-proof service.
  2. Opens and closes quickly.
  3. Small size compared to gate valves.
  4. It is lighter than gate valves.
  5. It has multi-way design flexibility which is not available in gate and globe valves. Therefore, it reduces the number of valves needed.
  6. Provides flexibility in selection with various ball valve designs.
  7. High quality ball valves provide safe service under high temperature and high pressure conditions.
  8. They are controlled with less force than gate or globe valves.

Disadvantages of Ball Valves

  1. Not suitable for permanent throttling.
  2. In sediment containing fluids, the impact and adhesion of the particles in the fluid to the seat surfaces causes wear, leakage and problem occurrence.

Advantages of Check Valves

They open and close by themselves. No external intervention is required for opening and closing. Opens and closes fast.

Disadvantages of Check Valves

  1. It is difficult to recognise whether the valve is open or closed from the outside because all its moving parts are in a closed housing.
  2. Check valves have various limitations during the installation phase.
  3. The valve disc can get stuck in the open position.

Advantages of Diaphragm Valves

  1. Used for opening – closing and throttling purposes.
  2. Due to the body inner coating, it provides good chemical resistance.
  3. Cover group is isolated from the fluid. Therefore there is no stem leakage.
  4. Provides bubble tightness.
  5. There are no pockets in the body that can cause debris and particle accumulation. Therefore, it is suitable for heavy fluids.
  6. Particularly suitable for hazardous chemicals and radioactive fluids.
  7. Due to the fact that the cover group is isolated from the fluid, it does not allow contamination of the environment with germs / dirt. Thus, it is hygienic for areas such as food industry, pharmaceutical industry, brewing industry.

Disadvantages of Diaphragm Valves

  1. The valve passage is obstructed, which prevents complete emptying of the pipeline.
  2. Depending on the diaphragm material, operating temperature and pressure are limited. It is generally used within 200 psi (14 bar) pressure and (204ºC) temperature limits.
  3. Hydrostatic pressure that can be applied to the diaphragm is limited.
  4. Diaphragm valves are limited in size. They are made sizes in DN15-DN300.

Advantages of Plug Valves

  1. It has a simple design with few parts.
  2. Easy to open and close (except large sizes)
  3. Maintenance and repair can be done at the place of use.
  4. Minimum resistance to flow.
  5. Provides reliable sealing.

Disadvantages of Plug Valves

  1. Due to high friction, it requires great power for the first actuation (opening and closing).
  2. NPS 4 (DN100) and valves larger than this size require gearbox or actuator.
  3. Depending on the conical plug, valve passages are narrowing type.
  4. In general, their costs are higher than ball valves.