Globe valves

Globe valves  that we are offering is widely appreciated owing to its top-notch quality, optimum performance, and ability to efficiently regulate the flow of fluids. This is a mechanical tool made up of the best quality material that has the capability to resist corrosion, and rust, and therefore, the valve is suitable for the abrasive liquids, and chemicals. Apart from this, Globe valves  is packed in a protective container that assures its safety during the transportation. 

Usmani valves Globe valves are used mainly for steam or other media where a throttling service is required. The seat design gives an advantage for doing this by utilising its globe shape as it comes down to connect with the seat effectively cutting the flow gradually up until it seals completely on the seat face. This however does cause a larger pressure drop than say a gate valve and causes turbulence in the line. The size, pressure class and material selection of all globe valves are the responsibility of the user or system designer. Process Systems may offer suggestions in this area, however the selection process is solely the responsibility of the end user or plant operator. 

Installation
Globe valves are unidirectional whereby they are only designed to take the flow in one direction, under the disc. There is an arrow of direction cast into the valve body but can easily be checked by looking into one end of the valve and see whether you are looking at the underside of the seat or above the seat. It is recommended that the valve be mounted vertically only whereby the hand wheel operation will be at the top of the valve. This ensures that no premature wear or damage will occur to the valve. The main installation points are below

Arrangement

Both the valve seat and the disc are arranged at right angle to the axis of the valve. The seat can either be screwed into the valve chest or can be a part of the body. The seating can either be flat or mitered and the stem would be threaded above or below the stuffing box. The spindle is held in the valve disc by a nut and the leakage is prevented using stuffing box, which is packed with packing material and gland.

Valve Seat

The valve seat can either be an integral part of the valve body or screwed into the body.

Backseats

Most of the valves have backseat arrangement a design which provides a seal between the stem and the bonnet. The disk seats against the backseat when the valve is fully open. This helps in preventing system pressure from building against the valve packing.

        Remove any packing or debris from the valve

        Ensure the inside of the valve is free from water or moisture (can expand when subject to heat on startup)

        Ensure the valve is supported (can be damaged by long runs of unsupported pipe clamping in on the valve)

        Ensure you have room to operate the valve

        Do a complete dry cycle of the valve from closed to open then back again

        Tighten flange bolts gradually in a diagonal pattern

        Gradually raise the internal pressure to ensure the flanges and bolts are installed correctly and the valve is sealed

        Raise internal pressure to operating levels and check again

Operation
Our Globe valves are clockwise close (anti-clockwise to open).

        Do not over tighten on the seat to close. If media is still leaking through the seat may be damaged

        Even though they are great for controlling flow try not to leave the disc in the middle of the flow for extended periods of time. This will cause the seat to wear prematurely and in steam applications where continuous throttling is less than 10% open, excessive vibration, noise and wire draw across the seat causing a leak path which at times may not be visual to the naked eye.

        Do not exceed 100% of the maximum pressure rating of the valve at any time during its operation. Pressure spikes or fluctuations beyond the valves pressure rating are solely the responsibility of the operator and can cause considerable harm or even death if not adhered to.

Maintenance
A regular maintenance and inspection schedule will ensure you get the best life and operation out of your globe valve. Some things to consider are below (not exhaustive).

        Regular inspection of the valve. Pay particular attention to the gland to ensure there is no obvious wear or the valve is leaking

        If the valve is not operated regularly it is a good idea to cycle the valve to ensure the disc is not bedding itself in the seat

        Grease the crossbar by using a grease gun on the grease nipple provided. Lubricate the spindle if needed

        Slightly tighten the gland bolts if the packing needs adjustment. Do not over tighten otherwise the gland will be damaged. If it is still leaking through here the gland packing may need to be replaced

        The gland packing of the valve is subjected to wear and tear and thus needs to be changed after sometime as the sealing quality will reduce.

         Moreover, continuous opening and closing of the valve leads to damage to the metal of the valve seat. Lapping paste is applied