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Valve seats: boring removal welded valve seats and restore geometries sealing

29 Mar 2019 - Uncategorised

Valve seats: boring removal welded valve seats and restore geometries sealing

Introduction

We would like to tackle a widespread problem in the field of valves maintenance.
In many cases there is the need to restore, or replace the Stellite sealing seats, or other hard metal, because they are damaged due to wear or other reasons that make them no more complying with their usage.

Sectors

Such need assumes a relevant importance when dealing with valves deputed to the management of special fluids (petroleum, oils, chemicals, etc.), in critical temperature and pressure conditions.
On these valves we can often find sealing seats made of stellite or other hard metal alloy.
Many fields are concerned by this subject, from the “petrochemical” to the “power generation“, up to the “valve manufacturers“, both in case of manufacturing defects, or in case of customers support.

 

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Cases

Two are the cases that may arise.
The first case concerns the sealing seats mounted to interference, where there is a seal welding to the valve body.
The second one concerns valves with seat seal obtained from an overlay welding made of stellite or other hard metal directly deposited on the valve body.
These situations require a boring process to solve the problem.

Our portable boring machines for rent are always available at request, as well as our skilled technicians for a service on site or consulting.


boring machine
Technology

In both cases, in presence of defects on the sealing  surface, it is necessary to remove the seal welding , or stellite (or other hard metal) overlay welding.
Nuova Simat can organize a service on site with a portable boring machining to:

  • remove the welding seam (whether seal welding or overlay welding)
  • repair the surfaces for the application of the new seat.

Our portable machine for boring is anchored to the valve body and performs the machining through special tools specifically designed .
With the same technology we can also execute

  • the removal of the welded parts
  • the machining of the new overlay welding

Using special pads it is possible to reach the final level of finish of the sealing surface of the valve seat.

Result

With our boring procedure, we can bring back the valve to its ideal working conditions.
Of course, it is not necessary to remove the valve from the line where is mounted, often by welding.
The intervention of Nuova Simat on a hard valve takes in average one working shift only.

The technical department in Nuova Simat can study customized solutions for any application, in order to solve the issue in the faster and most efficient way.


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