Mechanical Pressure Regulator for Cryogenic fluids

Abstract

A pressure regulator for fluids is described. The pressure regulator (100) has a main body (108) including a control valve (112,113) actuated by a control element (119) responding to a pressure signal generated by sensor means (118) to maintain a set pressure in the transfer line. The main body (108), the control valve (112,113), the control element (119) and the sensor means (118) are contained in an interior space (124) enclosed by a housing (123). A pressure below atmospheric pressure prevails in the interior space (124).

Claims

1. A pressure regulator for fluids, wherein the pressure regulator comprises: a main body including a control valve actuated by a control element responding to a pressure signal generated by sensor means to maintain a set pressure in a transfer line, wherein the main body, the control valve, the control element and the sensor means are contained in an interior space enclosed by a housing, and that a pressure below atmospheric pressure prevails in the interior space.

2. The pressure regulator according to claim 1, wherein the transfer line is a multiwalled transfer line, wherein the housing is connected with an outer tube of the multiwalled transfer line such that a ring space enclosed between the outer tube and an inner tube of the multiwalled transfer line is fluidly connected with the interior space.

3. The pressure regulator according to claim 2, wherein the interior space and the ring space are evacuated.

4. The pressure regulator according to claim 1, wherein the pressure regulator is enclosed in a gas-tight envelope whose interior is filled with a gas whose boiling point is below the fluid temperature.

5. The pressure regulator according to claim 1, wherein the pressure regulator is installed between an upstream section and a downstream section of the transfer line.

6. The pressure regulator according to claim 1, wherein the sensor means is a membrane.

7. The pressure regulator according to claim 6, wherein the sensor means further comprise a spring exerting a spring force on the membrane, wherein the spring is contained in the housing of the pressure regulator.

8. The pressure regulator according to claim 7, wherein the pressure regulator is provided with a pressure means, in particular a spindle, which enables a preload of the spring to exert adjustable forces on the spring so that different set pressures of the pressure regulator can be selected.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Exemplary embodiments of the present disclosure are illustrated in the drawings and are explained in more detail in the following description. In the Figures, the same or similar elements are referenced with the same or similar reference signs.

[0027] FIG. 1 shows a schematic cross-section of a pressure regulator according to the present disclosure.

DETAILED DESCRIPTION

[0028] FIG. 1 shows a mechanical pressure regulator 100 according to the present disclosure. The pressure regulator 100 is installed between an upstream section 101 and a downstream section 102 in a double-walled transfer line. The upstream section 101 of the transfer line comprises an inner tube 103a and an outer tube 104a. Likewise, the downstream section 102 of the transfer line comprises an inner tube 103b and an outer tube 104b. The inner tubes 103a,b enclose channels 106a,b, respectively, through which a fluid is transferred.

[0029] In the context of the present disclosure the term fluid is a placeholder for any kind of flowable materials that can have a solid, liquid or gaseous state of aggregation. In the following any kind of flowable material irrespective of its state of aggregation will be referred to as fluid including solid powders that can be pumped and flow through transfer lines like a liquid. Fluids in this sense also include aerosols and emulsions.

[0030] Ring spaces 107a,b between the inner and outer tubes 103a,b and 104a,b are evacuated to achieve vacuum insulation of the inner tubes 103a,b. In some embodiments the ring spaces 107a,b accommodate spacers and a superinsulation layer not shown in FIG. 1. The spacers inhibit the inner tubes 103a,b to get into direct contact with the outer tubes 104a,b. The superinsulation layer prevents radiation from entering into the inner tubes 103a,b. Both measures aim at limiting the heating up of fluid flowing inside the inner tubes 103a,b.

[0031] The upstream and downstream inner tubes 103a,b are connected with a main body 108 of the pressure regulator 100 in a fluid tight manner, for instance by welding. The channel 106a of the upstream inner tube 103a continues as a passage 109 in the main body 108. The passage 109 leads to a valve chamber 111 accommodating a valve element 112 that controls the size of a free passage of an outlet 113 of the valve chamber 111. The outlet 113 enters into a communication chamber 114 that is linked with a passage 116 which is fluidly connected with the channel 106b of the downstream inner tube 103b. Thus, the passages 109, 116, the outlet 113, and the communication chamber 114 establish a fluid connection between the channels 106a of the upstream inner tube 103a and the downstream inner tube 103b.

[0032] The communication chamber 114 is formed as a recess 117 in the main body 108. The recess 117 is closed by a membrane 118 in a fluid tight fashion. An inner side of the membrane 118 is connected with one end of an actuation rod 119. An opposite end of the actuation rod 119 is attached to the valve element 112. As a result, when the membrane 118 moves away from or towards to the main body 108 in response to an increasing and decreasing pressure inside the communication chamber 114, the valve element 112 moves in the same direction. The movement of the membrane 118 and the valve element 112 is indicated by double arrow 121 in FIG. 1. When the membrane 118 moves away from the main body 108, the valve element 112 decreases the size of the free passage of the outlet 113. As a result, the pressure in the communication chamber 114 decreases because the flow of fluid from the upstream inner tube 103a to the downstream inner tube 103b is reduced. When the pressure in the communication chamber 114 decreases the membrane 118 moves back towards the main body 108, which entails a corresponding movement of the valve element 112 to increase the free passage of the outlet 113 again. In consequence, the flow of fluid from the upstream inner tube 103a to the downstream inner tube 103b is increased and the pressure in the communication chamber 114 rises. In a stable situation a predetermined set pressure is achieved inside the downstream channel 106. The cooperation between the valve element 112 and the outlet 113 realizes the control valve controlling the pressure in the downstream transfer line.

[0033] The responsiveness of the membrane 118 to the pressure inside the communication chamber 114 is determined by the mechanical properties of the membrane and by a spring 122 that exerts a spring force on to the membrane 118. The design of the membrane 118 and the spring 122 determine a set pressure which is continuously controlled by the pressure regulator 100. In an embodiment the tension of the spring is adjustable by a spindle or the like. The spring 122, for instance a pressure spring 122, rests on an inner wall of a housing 123 of the pressure regulator 100. The housing 123 is connected in a vacuum tight manner on the one side with the upstream outer tube 104a and on the other side with the downstream outer tube 104b. The interior space 124 of the housing 123 is fluidly communicating with the ring spaces 107a,b of the upstream and downstream sections 101,102 of the transfer line. Thus, when the ring spaces 107a,b are evacuated, the interior space 124 is likewise evacuated and a vacuum insulation of the pressure regulator 100 is established. A minor thermal leak created by the mechanical contact between the spring 122 and the housing 123 can be minimized by design and proper choice of material. For instance, a layer of insulating material (not shown in FIG. 1) between the housing 123 and the spring 122 reduces the thermal conductivity between the cold part of the pressure regulator 100 and the housing 123.

[0034] When the interior space 124 of the pressure regulator 100 is evacuated, the reference pressure against which the set pressure is regulated is vacuum. Vacuum as a reference pressure enables the pressure regulator 100 to control set pressures below atmospheric pressure. For some fluids this can be an advantage.

[0035] In one embodiment the interior space 124 and the ring spaces 107a,b are filled with a gas whose boiling point is below the fluid temperature. In this embodiment the temperature of the fluid inside the inner tubes 103a,b is constant, namely at the boiling temperature of the gas.

[0036] Even though the pressure regulator 100 has been described in connection with a double-walled transfer line, the pressure regulator 100 is also applicable for multiwalled transfer lines having three and more walls.

[0037] In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a does not exclude a plurality.

[0038] A single unit or device may perform the functions of multiple elements recited in the claims. The fact that individual functions and elements are recited in different dependent claims does not mean that a combination of those functions and elements could not advantageously be used.

LIST OF REFERENCE SIGNS

[0039] 100 pressure regulator [0040] 101 transfer line (upstream section) [0041] 102 Transfer line (downstream section) [0042] 103 Inner tube [0043] 104 Outer tube [0044] 106 Channel [0045] 107 Ring space [0046] 108 Main body [0047] 109 Passage [0048] 111 Valve chamber [0049] 112 Valve element [0050] 113 Outlet [0051] 114 Communication chamber [0052] 116 Passage [0053] 117 Recess [0054] 118 Membrane [0055] 119 Actuation rod [0056] 121 Double arrow [0057] 122 Spring [0058] 123 Housing [0059] 124 Interior space