Refrigeration – Refrigeration producer – Compressor-condenser-evaporator circuit
Reexamination Certificate
2002-03-07
2003-05-13
Esquivel, Denise L. (Department: 3744)
Refrigeration
Refrigeration producer
Compressor-condenser-evaporator circuit
C062S498000
Reexamination Certificate
active
06560986
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to refrigeration systems and more particularly to refrigeration valves. The present invention is described herein in detail with respect to a conventional industrial refrigeration system. However, those of ordinary skill in the art to which the present invention pertains will readily recognize the broader applicability of the present invention. For example, the present invention may find application in a heat pump system or an air conditioning system or the like.
2. Related Art
Conventional refrigeration systems utilizes a recirculating refrigerant, such as ammonia, for removing heat from the low temperature side of the refrigeration system and for discharging heat at the high temperature side of the refrigeration system. The work input operating the system is provided by a motor driven compressor, which receives low-pressure gaseous refrigerant and compresses it to a high pressure. The high-pressure gaseous refrigerant is supplied to a condenser where heat is removed from the gaseous refrigerant to condense it to a liquid. The liquid refrigerant is then supplied through a control valve to an evaporator wherein heat is transferred from a heat transfer fluid to the liquid refrigerant. The gaseous refrigerant from the evaporator is then returned to the compressor for recirculation through the refrigeration system.
One method of feeding liquid refrigerant to the evaporator coil is known as the “recirculated” method. In this method, the evaporator is literally flooded by recirculating more liquid than the coils can evaporate. Evaporator coils work at optimum efficiency when their entire surface remains wet with liquid refrigerant. During the refrigeration cycle, a portion of the liquid in the evaporator is vaporized into gas. Gas and liquid exit the evaporator and are sent to a gas/liquid separator known as a recirculator. Liquid from the recirculator is sent to the evaporator.
Additionally, a receiver drum can be added between the condenser and the control valve to collect liquid refrigerant and absorb system flow fluctuation. The liquid refrigerant is sent to the control valve to decrease the pressure and temperature of the liquid refrigerant, which is then sent to the recirculator to flood the evaporator.
Conventional means of control consist of a solenoid valve followed by a throttling valve to reduce the pressure and govern the flow rate. There are several drawbacks to conventional means. The refrigerant flow, and hence the load due to flash gas, is intermittent, causing pressure fluctuations, which are detrimental to pump shaft seals and compressor capacity controls. Additionally, the combination of friction losses and ambient heat gain in the high-pressure liquid line preceding the control valve cause vaporization of some portion of the refrigerant producing vapor bubbles. Such vapor bubbles interrupt and reduce the mass flow rate of any throttling valve. Furthermore, the solenoid and throttling valve combination requires the use of numerous fittings and welds.
It is apparent that there is a need for a refrigerant control valve that smoothly modulates the flow of refrigerant, reduces the effect of vapor bubbles and has the capacity to control large systems with a single valve that is both slow closing and tight seating.
Therefore, it is an object of the present invention to provide a refrigeration valve that substantially eliminates vapor bubbles in the liquid refrigerant.
It is another object of the present invention to provide a refrigeration valve which functions as a shutoff valve, with or without a control signal or actuator power.
It is a further object of the present invention to provide a refrigeration valve that includes a condensation chamber for vapor bubbles flowing with liquid refrigerant.
Still another object of the invention is to provide a vertically oriented control valve to provide a chamber for entrained vapor in the liquid refrigerant to be collected and condensed.
Yet is another object of the present invention to provide a vertically oriented refrigeration valve that closes to a tight shutoff upon a loss of power.
It is an additional object of the present invention to smoothly regulate the flow of refrigerant in the system in response to the real time demand.
Other objects include the provision of ceasing fluid flow with one seal prior to fully seating on another seal to reduce wear on the seating seal.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a valve for use in a refrigeration system. The valve comprises an elongated housing having a longitudinal axis extending generally vertically and the housing has an inlet that extends generally perpendicular to the axis for receiving a high-pressure liquid refrigerant having traces of entrained vapor bubbles and an outlet for discharging liquid refrigerant and the flashgas generated from the drop in pressure through an outlet directed generally in the same direction as the axis. The housing further includes an upright outer shell having outside and inside surfaces, and an elongated upright inner hollow tubular member positioned inside the outer shell with its longitudinal axis coincident with the axis of the housing. The tubular member has an outer and inner surfaces and proximal and distal ends. The inside surface of the outer shell and the outer surface of the tubular member join to form a vapor bubbles condensation chamber. The chamber includes a collar mounted on the distal end of the tubular member and being affixed to and adjacent the inside surface of the outer shell. The outer shell includes an upper portion and a lower portion. The lower portion has top and bottom end sections wherein the high-pressure liquid refrigerant inlet is generally located medially between the end sections. The upper portion has top and bottom end sections wherein the top end section is part of the vapor bubbles condensation chamber. The tubular inner member has a plurality of vertically spaced passageways extending generally perpendicular to the axis and through the inner and outer surfaces of the tubular inner member. These passageways are located below the bubbles condensation chamber, thus ensuring pure liquid adjacent to the passageways. The tubular member has a long axis substantially coincident with the longitudinal axis. The outlet of the housing is spaced above an outlet of the tubular member and fluidly communicates with each other. The tubular inner member has a slide tube positioned outwardly of the tubular member for selectively closing and opening one or more of the passageways to permit high-pressure liquid refrigerant to pass therethrough in response to the system load requirements and discharge through the outlet. The tubular member includes a ring seal located spacedly above all of the passageways. The slide tube has an upper end portion, which completely closes against the seal to maintain the valve inoperative with the pressurized liquid and vapor refrigerant maintained within the valve housing. The slide tube has distal and proximal ends and includes a lip seal attached to and located adjacent the distal end of the slide tube for sealingly engaging the outer surface of the tubular member during sliding movement of the slide tube in closing and opening one or more of the passageways. The valve further includes a ring disk for sealing between the slide tube and the outer surface of the tubular member.
The valve also includes a movable flow controller means for moving the slide tube. The controller means includes an actuator positioned beneath and to the slide tube for moving the slide tube between open and closed positions. The open position involves exposing one or more of the passageways of the tubular member to permit pressurized liquid to pass therethrough and through the outlet in response to the system load while
Esquivel Denise L.
Norman Marc
Yeager Arthur G.
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