DE102005024889A1 - Cryo-compressor with double pressure valve - Google Patents

Abstract

It is a compressor, in particular compressors for cryogenic media, preferably for liquid hydrogen, comprising a cylinder wall surrounded by a compressor chamber in which a compressor piston is moved linearly, a suction valve and a pressure valve, wherein both valves are arranged in the region of the lower end position of the compressor piston , described. DOLLAR A According to the first pressure valve (D, D ') at least one further pressure valve (D1) is connected downstream.

Description

The The invention relates to a compressor, in particular compressors for cryogenic Media, preferably for liquid Hydrogen comprising a compressor chamber surrounded by a cylinder wall, in a compressor piston is moved linearly, a suction valve and a pressure valve, with both valves in the range of the lower end position of the compressor piston are arranged.

Under the term "cryogenic Media "are below so-called deep-frozen liquids, especially liquid Hydrogen, liquefied Natural gas, more liquid Nitrogen, more liquid Oxygen and other liquefied To understand gases.

compressor Any kind are well known in the art. All of them are mean that over a spring-loaded suction valve to be compacted medium in a Compressor room, compacted and then over a spring-loaded pressure valve is withdrawn from the compressor room.

The 1 shows in a laterally schematic sectional view of a generic, counting to the prior art compressor design.

Within one of a cylinder wall Z surrounded compressor space R is a compressor piston K 'linear moved back and forth or up and down. The two reversal points of the Compressor piston K 'be hereinafter referred to as the lower and upper end position of the compressor piston K '.

On the underside of the cylinder chamber, a suction valve S and a pressure valve D 'are arranged. About the suction valve S occurs during the suction cycle - while the compressor piston K 'moves from its lower end into its upper end position, in the present case from bottom to top - the liquid medium to be compressed in the compressor chamber R. During the subsequent pressure or compression stroke - the compressor piston K 'moves from its upper back to its lower end position, which in the 1 is shown - the compressed medium via the pressure valve D 'is pushed out of the compressor chamber R or pushed out.

Especially in the liquid compression a liquid Cryogenic medium is inevitably during training to training a gas phase G. It remains after the pressure or compression stroke in the unavoidable dead space of the compressor chamber R, so it comes during the subsequent suction cycle to a relaxation of the gaseous medium inside the compressor room R. During this relaxation can no new, liquid cryogenic medium over the suction valve S are sucked into the compressor chamber R. This thus has the consequence that the delivery of the compressor is substantially reduced.

Would be the dead space at the end of the pressure or compression stroke exclusively with liquid filled, could the prescribed, unwanted Relaxation of the gaseous Medium be prevented.

Also the 2 shows in a laterally schematic sectional view through a compressor design, as it is the subject of a non-prepublished German patent application of the Applicant.

In the in the 2 illustrated compressor piston K, whose head has a conical shape - area x - on. Furthermore, the pressure valve D is now arranged in the region of the lower end position of the compressor piston K laterally on the cylinder wall Z.

The compressor piston K is now at the end of the pressure or compression stroke in its lower end position - as in the 2 is shown, the remaining, filled with gaseous medium dead space G is now much smaller than that in the 1 illustrated compressor design.

moreover remains at the end of the pressure or compression stroke, a liquid phase F, by the moving in the lower end position compressor pistons K is not completely about that Pressure valve D expressed or can be pushed.

This has the consequence that at the beginning of the subsequent suction cycle a significantly reduced gas volume must be relaxed - if not even the remaining dead space is completely filled with liquid - before again liquid cryogenic medium over the suction valve S can be sucked.

It should be noted that in the 1 and 2 the sealing means to be provided between the compressor piston K 'or K and the cylinder wall Z are not shown for the sake of clarity.

By means of the 2 described compressor design is achieved; that the gas fraction in the compressor chamber R at the end of the pressure or compression stroke is completely eliminated or at least largely reduced; this results in a higher capacity compared to known compressor designs. Thus, a reduction in the specific compressor power relative to the Amount of subsidized or compressed medium can be achieved.

The in the 1 and 2 However, the compressor designs described above have in common that the unavoidable reflux of compressed medium via the pressure valves D 'or D reduces the delivery rate of the compressor since the liquid medium flowing back comprises the intake of "fresh" medium via the suction valve at least at the beginning of the cycle Suction cycle prevented.

Of Further will be during the pressure or compression stroke, the flowing back liquid medium due to at compaction inevitably resulting heat additionally heated in turn, a reduction of the liquid content and the flow rate of the compressor result.

task the present invention is a generic compressor, in particular a generic compressor for cryogenic Media to specify, in which avoided the aforementioned disadvantages can be.

to solution this task a generic compressor is proposed characterized in that the first pressure valve at least another pressure valve is connected downstream.

• – das oder die weiteren Druckventile derart angeordnet sind, dass sich zwischen dem ersten Druckventil und dem bzw. den weiteren Druckventilen eine Flüssigkeitssäule ausbildet,
• – das erste Druckventil im Bereich der unteren Endlage des Verdichterkolbens seitlich an der Zylinderwand angeordnet ist und der Kopf des Verdichterkolbens eine konische Form aufweist,
• – das erste Druckventil (D, D') ein lediglich flüssigkeitsdicht ausgebildetes Druckventil ist.

Further advantageous embodiments of the compressor according to the invention are characterized in that

• - The one or more pressure valves are arranged such that forms a liquid column between the first pressure valve and the or the other pressure valves,
• The first pressure valve is arranged laterally on the cylinder wall in the area of the lower end position of the compressor piston and the head of the compressor piston has a conical shape,
• - The first pressure valve (D, D ') is only a liquid-tight trained pressure valve.

The compressor according to the invention and further embodiments thereof, which constitute subjects of the dependent claims, are based on the in the 3 illustrated embodiment explained in more detail. The 3 shows the in the 2 surrounded with a dotted circle cutout of the 2 ,

According to the invention is now the (first) pressure valve D at least one further pressure valve D1 downstream. In principle, you can about that addition, additional Pressure valves are provided, however, the provision is in practice a further pressure valve D1 sufficient to the desired Effect to achieve.

The first pressure valve D and the other pressure valve D1 are now arranged such that between them in the line section L forms a liquid column, while in the line section L1 compressed gaseous medium located.

The Liquid column prevented effectively, the compressed gaseous medium via the pressure valve D can flow back into the compressor chamber R. It is thus sufficient if the first pressure valve D only liquid-tight is designed. Such pressure valves are constructed less complicated and cheaper as pressure valves, which are both fluid are designed as gas-tight.

Especially in compressors used for compressing cryogenic media is the problem of gas tightness of pressure valves is important, because of the back flowing gaseous medium additional undesirable Heat in the compressor space R or the compressor system is introduced.

The idea according to the invention can of course also be used in the case of 1 illustrated arrangement of the pressure valve on the underside of the cylinder space Z realize.

The associated with the compressor according to the invention Benefits are compared to a State of the art slightly more complicated compressor design bought; the ones associated with it However, additional costs are more than due to the advantages achieved compensated.

Claims (4)

Compressor, in particular compressors for cryogenic media, preferably for liquid hydrogen, comprising a cylinder chamber surrounded by a compressor chamber in which a compressor piston is moved linearly, a suction valve and a pressure valve, wherein both valves are arranged in the region of the lower end position of the compressor piston, characterized in that at least one further pressure valve (D1) is connected downstream of the first pressure valve (D, D '). Compressor according to claim 1, characterized that the one or more further pressure valves (D1) are arranged such that between the first pressure valve (D, D ') and the or the other pressure valves (D1) forms a liquid column. Compressor according to claim 1 or 2, characterized that the first pressure valve (D) in the region of the lower end position of Compressor piston (K) arranged laterally on the cylinder wall (Z) and the head of the compressor piston (K) has a conical shape (x) having. Compressor according to one of the preceding claims 1 to 3, characterized in that the first pressure valve (D, D ') only a liquid-tight trained pressure valve is.