Fluid handling – Self-proportioning or correlating systems – Supply and exhaust type
Patent
1988-08-15
1989-10-31
Nilson, Robert G.
Fluid handling
Self-proportioning or correlating systems
Supply and exhaust type
62278, 1376275, F16K 4900, F25B 4104
Patent
active
048770469
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a valve for shutting off or closing a main fluid flow through a main flow passage, comprising a valve stem having a valve head which may be operated to engage a valve seat in order to close said passage, the valve stem carrying at the end remote from the valve head a piston which operates in a cylinder and can be actuated by a closing fluid against spring action in order to move the valve stem and the valve head into closed position.
The valve according to the invention is especially designed for hot gas defrosting in freezing or cooling installations comprising a compressor, a condenser and an evaporator of the dry or filled type.
The compressor, which may be of the piston, worm, lamella or turbo type, draws the vapourous cooling agent from the evaporator and thereby maintains a low pressure therein. In the compressor the gas is compressed to the pressure determined by the operating condition of the condenser. Through the compression an amount of heat corresponding to the compression work is supplied to the vapour. This amount of heat together with that supplied in the evaporator is removed by heat exchange in the condenser, in which the cooling agent is condensed to a liquid. The liquid is then passed to a suitable throttling means in which the pressure is reduced to the pressure in the evaporator. By the reduction of the pressure a small amount of the liquid will evaporate, so that the remainder of the liquid reaches the evaporation temperature in operating condition. In filled evaporators liquid and gas will be separated in a liquid separator. The liberated amount of vapour from the pressure reaction is withdrawn to the compressor together with the amount of vapour formed by the supply of heat to the evaporator. Thereby the circuit is completed.
A filled evaporator system in general consists of a liquid separator associated with one or more evaporator sections. The liquid from the liquid separator is made to circulate either by automatic circulation or by forced circulation. In the case of a forced circulation it is possible to circulate far more liquid through the system (for instance 4 to 6 times more) than in the case of automatic circulation. The operating liquid head and the pressure losses in the system are clearly related, and especially an automatic circulation system must therefore be designed in such a manner that the pressure losses in the supply pipes and liquid passages are small.
A dry evaporator system has no liquid separator, and the pressure is reduced in the inlet to the evaporator by means of a suitable throttling means, usually a thermostatic expansion valve. The vapour leaves the outlet from the evaporator in dry-saturated or overheated condition.
Defrosting of the evaporator sections is necessary in case white frost and/or ice is formed on the outer surfaces of the evaporator because of the purpose and the operating condition of the installation. This will usually be an undesirable effect, but it can be utilized for the production of ice. For defrosting the evaporator sections hot gas may be used, which is supplied from the pressure side of the compressor or from a reservoir.
In principle a hot gas defrosting is performed by shutting off the entire evaporator system or parts thereof and supplying hot gas on the evaporator side of the closing point. This hot gas will largely condense in the interior of the passages in the evaporator, and the evaporator must be suitably drained, either to a suction accumulator, a return conduit or a liquid separator or to the remaining evaporator system. A suitable regulating system maintains the pressure in the defrosting section at the level providing an effective defrosting and drainage. When the defrosting is completed, the supply of hot gas should cease and the flow of cooling agent be resumed. The supply of hot gas can be designated as an injection, and as will appear from the preceding description it is to be effected on the evaporator side of the closing point and in the opposite direction of the closed cooling agent
REFERENCES:
patent: 3034527 (1962-05-01), Hennels
patent: 3498056 (1970-03-01), Avery
patent: 3519011 (1970-07-01), Pennanen
patent: 3665723 (1972-05-01), Okutus
patent: 4057074 (1977-11-01), Fischer
patent: 4279129 (1981-07-01), Cann
Albrigtsen Rolf H.
Samuelsen Per R.
A/S Finsam International Inc.
Nilson Robert G.
LandOfFree
Closing and injection valve especially for hot gas defrosting in does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Closing and injection valve especially for hot gas defrosting in, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Closing and injection valve especially for hot gas defrosting in will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-620917