WO2013062431A1

WO2013062431A1 - High-temperature mechanical seal with double (extra) internal cooling

Info

Publication number: WO2013062431A1
Application number: PCT/PT2012/000045
Authority: WO
Inventors: Rui Vitor SILVA NEVES
Original assignee: Silva Neves Rui Vitor
Priority date: 2011-10-27
Filing date: 2012-10-27
Publication date: 2013-05-02
Also published as: PT105972A

Abstract

The mechanical seals present in almost all types of industries (petro-chemical industry, for example) involve high temperatures in the pumping processes and need to be improved in view of the cost. The existing solutions have sealing elements which collapse when exposed to high temperatures. Rare and expensive materials are used to restrain the failure and consequent intervention, but the heat transfer persists. Through mechanical construction is created an inner zone which can be fully closed (13, 14), in which a fluid circulates promoting heat exchange zones which would not be accessible. More important than that is the increased lifespan and reduced mechanical seal interventions. A leak can be something extremely dangerous and may be the cause of immeasurable loss.

Description

description

High Temperature Mechanical Seal with Double (Extra)

Internal cooling

TECHNICAL FIELD OF THE INVENTION

This invention has application in almost every type of industry where large thermal gradients inherent in fluid pumping processes, such as petrochemicals, are involved, as existing solutions have collapsible sealing elements and lose their properties. properties when exposed to these temperatures.

PREVIOUS TECHNIQUE

Currently the sealing systems to which this invention fits are standardized according to API 610 / ISO 13709, API 628 and ISO 20149 standards.

Several sealing systems and combination sets are available worldwide trying to solve every situation, such as the bellows joint packing, which allows not to use springs but a metal bellows that gives it flexibility and the absence of the joint to the shaft.

However when pumps stop and although there are several cleaning and temperature control systems in place, the pumped fluids go through a variety of physical and chemical states and come into contact with the packing components. In the start-up phase, part of the fluid is still rigid (co-cooled) causing the packing to collapse.

This invention, by means of mechanical construction and assembly of components, is intended to make a fluid that will circulate inside various packing components completely or not, and will be responsible for further controlling the temperature in areas previously impossible. to arrive.

In this way it is possible to avoid the problems of the bellows joints, the distancing of the secondary joint to a thermally less critical zone and the possibility of using springs. DESCRIPTION OF THE FIGURES

Mechanical packing parts set as per drawing

Cut A-A and Cut B-B and following table:

DETAILED DESCRIPTION OF THE INVENTION

Being a very standardized area and with implementation in all types of industry, if we restrict ourselves as an example to the petrochemical industry, this approach creates another space for improvement in procedures and equipment utilization that until now could not be covered.

The mere question of the often precarious technical knowledge on the part of the equipment assemblers gives rise to potential yield losses.

The longer it lasts, the harder it works and the less intervention, this "small" technical innovation will provide a substantial improvement of equipment.

The available applications have flaws promoted by the arrangement and constitution of the various elements of the mechanical seal. This extra and controlled internal cooling, added to existing ones, will allow a rethink of its composition and promote arrangements with materials under more favorable conditions. Operation :

An additional feature of the invention is the possibility to introduce in a controlled and enclosed packing a fluid which, by circulating, will allow to control the temperature within the parts in which it contacts and, by convection, make it possible to improve the temperature for the stress-resistant characteristics of the remaining aggregate packing components. In the drawing - Cooling Flow, the flow channels of the fluid are represented as an example.

Application:

Applicable on request and in accordance with the reference standards already indicated, through the most suitable and economical fluid, in pumping equipment with large thermal gradients and working with products of extreme danger.

Usage:

Direct application to pumping equipment through a cartridge seal to which an open or closed circuit will be connected through which the refrigerant will pass and can be connected to a wide range of refrigeration equipment as well as a simple compressed air, which in this case is easily accessible and low cost given its widespread availability in the industries.

Goal :

Locally cool packing areas where there are sealing elements that need to have a thermal environment more compatible and / or favorable with their use properties to ensure sealing.

Explanation:

In a packing with a standard structure, another type of refrigeration not previously contemplated is added.

In the example shown, using the Mechanical Seal Packing Cap (10), obtained by chip starter, a cavity that arises after being assembled with a

Cap closure bushing (6) and Gaskets (7) and (9).

Packing Cap (10) is pre-machined where holes are drilled through which internal extra coolant will circulate in addition to those used.

Mounting the Lid Lock (13), Lid Lock (14), and the Inner Ring Cover (31) Secondary Stationary (10) will promote the creation of a cavity where the internal extra cooling fluid will circulate.

Cover Latch (13), Internal Cover Bushing (31) may, depending on the application, provide the cooling outlet, eventually covering other components and eventually dissipating in a controlled or uncontrolled manner to the outside.

This extra cooling of internal cooling will thermally change the area where the 0 'ring (19) and the Joints (7) are placed, allowing the placement of the Stationary Ring Bushing (5) that supports the Stationary Ring (4). This configuration of the Primary Rotary Ring Bushing (5) is simpler and much more economical to perform and has the advantage that it does not suffer from the adherence of the fluid to be pumped compared to the best available technique so far as the use of packing. bellows.

The bellows packing ends up impregnating the fluid to be pumped, which removes its flexibility, causing rigidity and consequently affects the sealing surface due to deterioration of the faces.

The Stationary Ring Bushing (5) can thus be fitted with a set of spring (20) which is protected and which ensures the positioning of the sealing faces (3) and (4). It is still reusable and suitable filler material may be deposited to be more wear resistant to the gasket (7) and O 'ring (19).

The second zone ^a seal (12) and (23), such as for example, an area thermally affected by the extra cooling of internal cooling by providing best conditions for O 'rings will proportionally (24) and (27).

The Secondary Stationary Ring Bushing (23) will benefit from the same situation as the Stationary Ring Bushing (5).

In addition, the possibility or not of being able to provide cooling to the space between the pieces (18), (22), (23), (31) and (32).

This can also interfere thermally and create better operating conditions in the shaft seal O 'ring (32) through the sleeve (18).

This proposal for assembling the mechanical seal constituents, presented here as an example, will provide a spacing of the most thermally sensitive parts, which will make their longer, thus more economical use time. Advantages of the Invention:

Just take as an example just the daily world crude oil extraction, which according to the US Department of Statistics in 2009 was 62,689 million barrels per day and only in the top 15 oil producing countries. All this process is associated with the crude pumping process and as such the presence of mechanical packing.

The current mechanical packing, for the reasons already explained, eventually diminish its function, giving way to the fluid, causing a number of situations, which may take on extremely dangerous proportions, causing shutdown and consequent need for intervention in the equipment. All of this workforce is unquantifiable and hardly accounted for, as is the availability of expensive replacement parts that are often not readily available.

If the invention allows an increase in the life of the mechanical seal, it will consequently make the use of the remaining equipment available for a longer time, making the whole process more effective and efficient, avoiding costs inherent to the equipment shutdown intervention.

More collaterally, we will have environmental benefits with respect to decreased pollution and decreased use of natural and material resources.

ESSENTIAL TECHNICAL CHARACTERISTICS

The set of packing parts are obtained by cutting, cutting or molding machining are the same as those currently in use, with this invention allowing to control the path of the fluid to be cooled. This is where innovation occurs, as another form of construction and availability of packing components is made possible.

1. Shaft Seal - characterized by the positioning of the Shaft seal O 'ring (32) through the Sleeve (18) as it can be relocated further away from the most critical thermal zone, leaving it in a position to maintain its mechanical properties longer;

2. Changing the thermally affected zone - characterized by the extra cooling of internal cooling that will thermally change the area where the O 'ring is placed (19). and to Joints (8), allowing the placement of the Stationary Ring Bushing (5) that supports the Stationary Ring

(4). This configuration of the Stationary Ring Bushing

(5) is simpler and much more economical to perform, having the advantage that it does not suffer from the adherence of the fluid to be pumped compared to the best available technique so far as the use of bellows packing. The bellows packing ends up impregnating the fluid to be pumped, which removes its flexibility, causing rigidity and consequently affects the sealing surface due to deterioration of the faces.

Bush assembled with a spring assembly characterized by the fact that the Stationary Ring Bush (5) can thus be fitted with a spring assembly (20) which is protected and which ensures the positioning of the sealing faces (3). ) and (4). In this case it is still possible to reuse and a suitable filler material can be deposited to be more resistant to the wear of the joint (7) and O 'ring (19).

Extra cooling of internal cooling in O ^x rings

- The second zone of ^the seal, as in the example, a heat affected zone by additional cooling will cooling internal proportional providing best conditions for O 'rings (24) and (27).

Extra cooling of internal cooling in the Bushings - characterized in that the Secondary Stationary Ring Bushing (23) will benefit from the same situation as described in the Stationary Ring Bushing (5) which supports the Stationary Ring (4). Providing cooling to other parts characterized in that it also adds the possibility that cooling may be provided to the space between parts (18), (22), (23), (31) and (32).

Increased uptime - characterized by the fact that this proposal for assembling the mechanical seal constituents, presented here as an example, will provide a spacing of the most thermally sensitive parts, which will make their longer, thus more economical, use time.

Claims

ESSENTIAL TECHNICAL CHARACTERISTICS The packing set parts are obtained by chip-starting, cutting or molding machining are the same as those currently in use, with this invention having to control the path of the fluid to be cooled. This is where innovation occurs, as another form of construction and availability of packing components is made possible.

1. Shaft Seal - characterized by the positioning of the Shaft seal O 'ring (32) through the Sleeve (18), as it can be relocated further from the most critical thermal zone, leaving it in a position to maintain its mechanical properties longer;

2. Changing the thermally affected zone - characterized by the extra internal cooling cooling that will thermally change the area where the O 'ring (19) and Gaskets (8) are placed, allowing the placement of the Stationary Ring Bushing (5) that Supports the Stationary Ring

(4). This configuration of the Stationary Ring Bushing

3. Bush assembled with a spring assembly characterized in that the Stationary Ring Bush (5) can thus be fitted with a spring assembly (20) which is protected and which ensures the positioning of the sealing faces. (3) and (4). In this case it is still possible to reuse and a suitable filler material can be deposited to be more resistant to the wear of the joint (7) and the 0 'ring (19).

4. Extra cooling of internal cooling in O ^x rings

- The second zone of ^the seal, as in the example will proportionally by a thermally affected zone extra cooling for internal cooling, providing better operating conditions for O-rings (24) and (27).

5. Extra cooling of internal cooling in bushings - characterized in that the Secondary Stationary Ring Bushing (23) will benefit from the same situation as described in the Stationary Ring Bushing (5) which supports the Stationary Ring (4).

6. Make refrigeration available to other parts

characterized in that it further adds the possibility that cooling may be provided to the space between parts (18), (22), (23), (31) and (32).

7. Increased uptime - characterized by the fact that this proposed assembly of the mechanical seal constituents presented here, as an example, will provide a spacing of the most thermally sensitive parts, which will make their longest use time , therefore more economical.