Gas intensifier with lubrication

Abstract

A hydraulically driven intensifier for increasing pressure of gas comprising a piston-driven compression chamber for gas, operatively connected to an adjacent hydraulic chamber, with lubricant coupling in the compression chamber of the intensifier to circulate the lubricating fluid for cooling and lubricating the piston. A multistage compression system for gas, comprising the aforementioned intensifier, preferably several thereof operatively connected in series.

Claims

1. A hydraulically driven intensifier for increasing pressure of gas, said intensifier comprising a piston-driven compression chamber for gas, operatively connected to an adjacent hydraulic chamber further comprised in the intensifier, characterized by a lubricant coupling in the compression chamber of the intensifier to circulate a lubricating fluid at least within an intermediate space, between the piston and the hydraulic chamber, for cooling and lubricating the piston.

2. The intensifier of claim 1, wherein the flow of hydraulic fluid and the accompanying change in volume of the intermediate space cause formation of a vacuum or generally reduced pressure therein, which may enhance flow of lubricant into said space.

3. The intensifier of claim 1, wherein the lubricant coupling comprises an inlet and an outlet, through which lubricant enters and exits the compression chamber, said inlet and outlet further comprising a pipe or tube, and/or a check valve.

4. The intensifier of claim 3, wherein the inlet and outlet connect a vessel in which the lubricant resides to the intermediate space of the compression chamber, constituting a circulation of the lubricant.

5. The intensifier of claim 1, wherein the lubricating fluid is the same hydraulic fluid, preferably liquid, more preferably hydraulic oil, that is used in the hydraulic chamber.

6. The intensifier of claim 1, comprising a second compression chamber operatively connected to the hydraulic chamber, located on the opposite site of the hydraulic chamber to the first compression chamber.

7. The intensifier of claim 1, wherein the intensifier is utilized for increasing the pressure of biogas or natural gas.

8. The intensifier of claim 1, comprising at least one element selected from the group consisting of: pump, electric pump, motor, and electric motor; the at least one element being provided in order to circulate lubricating and hydraulic fluid.

9. A multistage compression system for gas, comprising the intensifier of any preceding claim, preferably several thereof operatively connected in series.

10. A method for compressing gas comprising utilizing a hydraulically driven intensifier to increase the pressure of gas, said intensifier comprising a piston-driven compression chamber for gas, operatively connected to an adjacent hydraulic chamber further comprised in the intensifier, wherein a lubricant coupling is employed in the compression chamber of the intensifier and the lubricating fluid is circulated at least within an intermediate space of the compression chamber, between the piston and the hydraulic chamber, to cool and lubricate the piston.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be described in greater detail with reference to the accompanying drawings, in which:

[0010] FIG. 1 illustrates one embodiment of a gas intensifier (unit) according to the present invention.

[0011] FIG. 2 shows the flow of fluids in one of the gas chambers and the hydraulic chamber of the intensifier.

[0012] FIG. 3 is a multistage compression arrangement comprising several intensifier units according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0013] FIG. 1 depicts one embodiment of a compressor device preferably in the form of an intensifier, or booster, according to the present invention intended for increasing the pressure of a gas. That is, compression of gas using a compressor arrangement is the matter that is discussed. In some embodiments, the gas that the intensifier, or compressor, may be used to increase the pressure of may include biogas or natural gas.

[0014] The term intensifier unit refers hereafter to an intensifier device which comprises one (common) body of preferably rigid type. In some embodiments, the body may be of substantially monolithic nature defined by a single element or several permanently attached elements. In some other embodiments the body may comprise multiple functional elements such as chambers removably connected together by necessary fixing elements such as bolts.

[0015] In the shown embodiment, a single-stage double-acting intensifier unit is presented, but the fundamental principle of the invention may be utilized in a multi-stage intensifier unit. A single-acting intensifier unit is also feasible according to the present invention.

[0016] The intensifier (unit) 100 of FIG. 1 is presented as an oblong object in which the functional chambers are successively placed, but other shapes are also possible. The outward appearance of the intensifier 100 could generally resemble e.g. a cylindrical or rectangular tube defined by the outer walls of the successive chambers. According to the depicted embodiment, a gas chamber, essentially a gas cylinder 102, structurally preferably defining a substantially cylindrical shape also geometrically, is operatively connected to a hydraulic chamber or cylinder 104, which may further be connected to a second gas chamber 106. The operational connection is carried out by coaxially conjoining the fluid pistons 108, 110, and 112 of the chambers by at least one connecting element such as a plunger or rod 114. The gas chambers or, according to their intended use, compression chambers, 102, 106 comprise gas inlets 118 and 130, through which the uncompressed gas enters the chambers 102, 106, and outlets 120 and 128, through which compressed gas exits the chambers 102, 106.

[0017] In the embodiment of FIG. 1, the lubrication coupling is implemented through the lubrication fluid inlets 124 and 132 and lubrication fluid outlets 126 and 134. The aforementioned inlets and outlets 124, 126, 132, 134 of the gas chambers typically comprise, or are at least connected to, a pipe, tube, or other conduit, and a preferably check type valve for funneling the lubrication fluid in the proper direction.

[0018] The gas chambers may be separated from the hydraulic chamber by suitable separating elements 136 and 138 which may comprise one or more parts, such as a hydraulic connection rod seal assembly and a connection block or flange or other such suitable structures.

[0019] The hydraulic chamber 104 comprises inlets/outlets 116, 122 (whose inlet/outlet roles may change dynamically depending on the current working direction of the piston 110 as being easily appreciated by a person skilled in the art) for hydraulic fluid flow. In some embodiments the chamber, piston, rod, pipe(/tube/conduit), and/or separating element materials may generally include e.g. metal, alloy, cast iron, plastics, steel, stainless steel, aluminum, brass, bronze, ceramics, and/or nickel-alloy.

[0020] From a functional point of view, gas is brought into the first gas chamber 102 through an inlet 118, which permits flow into the chamber, while compressed gas exits the gas chamber 102 through the outlet 120, which permits flow out of the chamber 102. The second gas chamber 106 may have a substantially similar configuration with the inlet 130 and outlet 128.

[0021] Compression of gas in the chamber 102 is effectuated through the flow of hydraulic fluid. Hydraulic fluid that is conducted into the hydraulic chamber 104 via the inlet 116 causes the piston 110 to move, which, through the connecting rod 114, causes the fluid piston 108 to move, thereby compressing the gas in the gas chamber 102.

[0022] The compressed gas exits the chamber 102 via the outlet 120 and the direction of flow of the hydraulic fluid is reversed, allowing uncompressed gas to be recurrently conducted into the gas chamber via the inlet 118.

[0023] The work cycle in the chamber 106, which in the embodiment of FIG. 1 is on the other side of the hydraulic chamber 104, is substantially opposite, i.e. the compression of gas therein 106 occurs while the uncompressed gas is conducted into the chamber 102.

[0024] In a multi-acting intensifier unit, the alternating direction of flow of the hydraulic fluid thus determines in which gas chamber 102, 106 the compression takes place.

[0025] In terms of lubrication, in various embodiments the lubricating fluid may be fed into the first gas chamber 102 through the inlet 124, situated e.g. next to the separating element 136, and exit the chamber 102 through the outlet 126, a similar arrangement being generally suitable also for the second gas chamber 106, with corresponding inlet 132, outlet 134, and separating element 138.

[0026] An embodiment of the flow of fluids to and from the first gas chamber 102 and the hydraulic chamber 104 of the intensifier of FIG. 1 are seen at 200 in FIG. 2.

[0027] In this embodiment, gas not yet compressed by the intensifier 100 is conducted from a storage unit 202 into the intermediate space (volume) 102a, residing between the gas inlet 118 or outlet 120 and the fluid piston 108 within a gas chamber 102. After compression, the gas travels through the outlet 120 into a storage unit 204 intended for the compressed gas.

[0028] The hydraulic fluid that drives the compression is conducted to and from the hydraulic chamber 104 through the inlet and outlet 116 or 122, respectively. The fluid may be supplied from the hydraulic fluid reservoir 206, into which it may also be returned. The hydraulic fluid may, for instance, be hydraulic oil or other fluid that is suitable for the application.

[0029] In one embodiment, as the piston 108 is being driven to compress the gas by decreasing the volume 102a, the volume of the substantially neighboring space 102b, located between the piston 108 and the separating element 136, increases, leading to the formation of a vacuum or generally a space of lower pressure in contrast to the environment including the inlet 124 and/or reservoir 208, which will cause or at least facilitate lubrication fluid to flow into the space 102b through the inlet 124 and/or at least spread therein. A similar setup may be employed in the second gas chamber 106.

[0030] In the embodiment of FIG. 2, the volume of space 102b decreases as the direction of movement of piston 108 is reversed with the reversal of the direction of flow of the hydraulic fluid, causing a pressure increase and leading or at least facilitating the lubricating fluid to flow out of the space 102b through the outlet 126 and back into the lubricator reservoir 208, thus creating or enhancing a circulation of the lubricating fluid.

[0031] In alternative or supplementary embodiments, at least one drive entity 210 may be employed, comprising one or more elements such as pumps for circulating the hydraulic fluid and/or lubricant. E.g. electric motor(s) may be utilized to drive the pump(s) or other circulation-enhancing mechanism of the hydraulic and/or lubricating fluid.

[0032] The lubrication fluid, typically essentially liquid, may in various embodiments optionally be the same fluid that is used as hydraulic fluid, e.g. oil. Alternatively, different lubrication fluid such as different oil may be utilized.

[0033] In the embodiment of FIG. 2, the lubrication fluid is contained in a separate lubricator reservoir 208, but in other embodiments one or more common elements such as a reservoir, pump and/or motor, could be utilized among the hydraulic and lubrication circulation systems.

[0034] Two or more intensifier units 100 may be coupled to implement a multistage compression system. In FIG. 3, three intensifier units 100a, 100b, and 100c, with structure according to FIG. 1, form an arrangement that may be used for multistage gas compression. The gas chamber volumes of unit 100b may be smaller than that of unit 100a, and the gas chamber volumes of unit 100c may be smaller than that of unit 100b. The uncompressed/original state gas enters the intensifier unit 100a through the inlet 118a and leaves the unit after compression through the outlet 120a. This gas, after one stage of compression, enters the intensifier unit 100b through the inlet 118b, and is further compressed, after which it passes through the outlet 120b and is conducted to the intensifier unit 100c through the inlet 118c. In the embodiment of FIG. 3, the gas is thus compressed in three stages. Accordingly, after compression in unit 100c, the gas is discharged through the outlet 120c, and is passed to a storage unit. By way of example only, compression ratio of one unit or stage may fall within range from about 2:1 to about 20:1.