These valves usually remain in position for long periods of time and may be hard to operate and/or not function as well as when originally installed. This reduction or operability can result from either a loss of effective lubricants in the stem threads, aging of packing, surface corrosion of moving parts, or an accumulation of deleterious solids. Wal-Tech Valve recommends scheduled periodic partial or full cycle exercising of these valves. Our sales representatives can customize the best program for your application.
Gate valves are usually for on-off service. These valves should be operated fully opened or fully closed, never in a partially closed position due to the stress on trim. They usually have a very low pressure drop and are used regularly for isolating equipment that may have to be maintained.
Globe valves are primarily used for throttling. These valves are designed to operate in a partially opened position. Several disc designs exist and care should be taken in evaluating the correct design for your application. This should be decided based on the flow conditions of the system. Globe valves are not pressure-reducing valves, they strictly limit the amount of media that can flow through the valve. Wal-Tech Valve has the expertise to help repair or pick out the right valve for your application.
Check valves are used to prevent reverse flow. These valves are most often used to protect rotating equipment such as pumps or turbines from the effects of flow reversal. There are many designs such as lift check, swing check, double disc check, piston check, nozzle check, etc. Wal-Tech Valve has the ability to handle in shop or on-site repairs. Let our skilled representatives help evaluate and determine the best solution for your check valve maintenance.
Ball Valves and Plug Valves are recommended to be in the full open or full closed position. Smaller ball and plug valves are sometimes used in balancing applications where they are set in a partially opened position and left for a long period of time. This is not recommended because the flow wears on the seat, which is exposed in this partially open position. Eventually the valves will not close because of this seat wear. This is the valve of choice when seating material limitations are within the system's normal operating conditions because of the ease of the quarter turn operation. Floating ball and trunnion mounting of the ball are different design choices that need to be made based on system conditions. Wal-Tech Valve can repair and sell these valves. Let us quote your specific valve need!