US2749925A

US2749925A - Pressure regulating device

Info

Publication number: US2749925A
Authority: US
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 LONG 2,749,925

PRESSURE REGULATING DEVICE Filed Nov. 29, 1951 22 m y I i 20 INVENTOR.

L. L. LONG A 7' TORNEK?- United States Patent "Ofice 2,749,925 Patented June 12, 1956 PRESSURE REGULATING DEVICE Loren L. Long, Alvin, Tex., assignor to Phillips Petroleum Company, a corporation of Delaware Application November 29, 1951, Serial No. 258,846

7 Claims. (Cl. 137-1) This invention relates to pressure regulating devices. In one of its aspects this invention relates to a pressure regulating device in combination with a vortex tube. In still another of its aspects this invention relates to a method and apparatus for the prevention of plugging or freezing of a pressure regulating device.

When a pressure regulating device is employed to ,pass a gas at a relatively high pressure to a relatively low pressure difficulties are often encountered in the operation of these valves due to the formation of ice or solid materials such asgas hydrates. Ice and/or gas hydrates are-often formed in natural gas lines due to the reduced temperature of the gas after having passed through a pressure regulating device from a high pressure zone to a low pressure zone. In natural gas collecting and distributing systems freezing and plugging of back pressure regulating devices and pressure relief valves are often encountered due to the formation of ice and'solid gas hydrates on the outlet side of these devices. In the handling of natural gas at high pressures and with water vapor therein gas hydrates are easily formed. Gas hydrates are essentially a solid molecular complex of a paraflinic hydrocarbon such as methane, ethane, propane, butane, isobutane, etc. and water, a typical gas hydrate can be represented by CH4.7H2O. Depending upon the pressure and temperaturethese hydrocarbons form solid hydrates with water vapor. Solid gas hydrate forming conditions are found within the temperature range 3090 F. and form about 10 to 10,000 p. s. i.g.; in general the higher the temperature the higher the pressure necessary to form solid gas hydrates.

'In natural gas collecting and distributing systems pressure surges are oftentimes experienced. These pressure surges may reach dangerously high values. In order to prevent pressure in natural gas systems from reaching dangerously high levels, pressure release valves are incorporated therein. These pressure release-valves are set or adjusted to release a high pressure gas at certain predetermined values. In operation however, difiiculty is encountered due to the formation of solid gas hydrates or ice on the outlets of such valves. In actual practice it has beenfoun'd that when a pressure relief valve opens to pass gas therethrough in order to reduce the pressure in that particular part of the system, solid gas hydrate formation sometimes occurs due to the rapidand sudden expansion of the gases. The solid gas hydrate often plugs the outlet side of the pressure relief valve and effectively shuts off the flow of -high pressure gas therethrough.

When this condition occurs there is great danger of failure of some part of the system due to the high pressure. Another difiiculty encountered in the operation of these valves is the formation of ice therein due to the rapid cooling of the gas as it expands through the pressure release valve.

Accordingly, it is an object of this inventiontoprovide an improved pressure regulating device. It is another object of this invention to provide a means and method for the prevention of solid gas hydrate formation within a mosphere.

pressure regulating device. It is still another object of this invention to provide a means and method of maintaining pressure regulating devices at an elevated temperature to prevent plugging by ice or gas hydrates. Other objects, features and advantages will be apparent and suggest themselves to those skilled in the art from the accompanying drawings and disclosure. In at least one aspect of this invention, at least one of these objects will be achieved.

In accordance with my invention I have provided an apparatus and method for preventing the formation of solid gas hydrates and ice within a pressure regulating device. My invention comprises a pressure regulating device in combination with a vortex tube. In accordance with one embodiment of my invention highpressuregases upon passing through a pressure regulating device enter a vortex tube. The gaseous effluent from the hotend of the vortex tube is then passed in heat exchange relation- .ship with the pressure regulating device. These hot gases from the vortextube are employedto heat and increase the temperature of the pressure regulating device so as to .prevent formation of solid ice or solid gas hydrates therein.

The vortex tube is a device which is well known and comprises essentially a tube wherein a gas is admitted tangentially. Due to the configuration of inner surfaces of the vortex tube the gas is separated into two streams, a relatively high pressure, high temperature stream and a relatively low pressure, low temperature stream. These streams may be separately recovered from the vortex tube. Depending upon the temperature and pressure ,of the entering gases to the vortex tube and depending upon theparticular design of the vortex tube, the temperature differential between the hot stream and the coolstream issuing from the vortex tube may range between 50250 F. Higher orlower temperature differentials of course may be obtained depending upon the particular design of the vortex tube. Fora more complete-understanding of the vortex tube, how it is constructed and for a description of how a high and a low temperature stream is produced, reference is made to'U. S. Patent 1,952,281. The disclosures of this patent relative to the construction and operation of a vortex tube are herein incorporated and made a part of this disclosure.

The invention will be better understood and the method and apparatus of this invention will become more apparent from the following discussion made with reference to the accompanying drawings Figs. 1, 2, and 3 wherein Fig. l is across-sectional side view of one embodiment of this invention showing a vortex tube in combination with a pressure relief valve and wherein Fig. 2 is a cross-sectional plan view of the same device illustrated by Fig. 1 and wherein Fig. 3 is a cross-sectionalplan view of a typical vortex tube.

Referring now to Fig. 1, a jacketltl is shown enclosing valve body'll. A conduit 12 is shown connectedto valve body '11 and'communicating with a suitable source of high pressure gas, such as container 13. The outlet end of conduit 12 within valve body 11 is closed by a suitable valve, plug 15 which is positioned thereover;by pressure responsive meansjld, such as a spring, so as to maintain plug 1'5 in position to seal off the outlet end of;conduit 12 within valve body '11. Con'duit 18 communicates the interior of valve body '11 with vortex-tube:19. Vortex tube 19 has two outlets, a low temperature outlet 720 and a high temperature outlet 21, and an inlet 26. 'The low temperature outlet may be connected by,conduit 22 torany suitable system or may lead directly to the at- Conduit 23 connects the high temperature outletof vortex tube19 with jacket 10. Jacket10 is provided with an outlet 25.

Referring now to Fig. 2 there is shown a cross-sectional plan view of the apparatus illustrated by Fig. 1. Those clarity in order to better understand how a vortex tube is incorproated in a pressure regulating device in accordance with this invention.

Referring now to Fig. 3 therein is shown a crosssectional plan view of the vortex tube employed in the apparatus of Fig. 1. Fig. 3 shows inlet 26 to the vortex tube and the inner surface 27 of the vortex tube.

The operation of the apparatus of the invention is simple. Whenever pressure responsive means 16 is caused to move upward or is compressed due to the pressure of the gas in conduit 12, valve plug 15 is moved off the outlet end of conduit 12. As a result gas will flow through conduit 12 into valve body 11 through conduit 18 into vortex tube 19. Since a lower pressure exists at each of the outlets of the vortex tube than at the inlet to the tube, the entering gas will flow out of both of the outlets. Substantially all of the gas flowing out of low temperature outlet 20 comes from the center of the tube while substantially all of the gas flowing out of high temperature outlet 21 is collected from the periphery of the tube. This latter gas is at a substantially higher temperature than the gas removed from the center of the tube. Whether an outlet serves as a high or low temperature outlet depends entirely upon the construction of the vortex tube. By merely altering the construction of the tube so that the direction of flow of the hot and cold gases is reversed, an outlet can be changed from a high to a low temperature outlet or vice versa. The low temperature, cold stream from outlet 20 of the vortex tube enters conduit 22 and is suitably recovered or utilized. The high temperature, hot stream from outlet 21 of the vortex tube is passed via conduit 23 into jacket wherein it is passed in heat exchange relationship with valve body 11. The hot gaseous stream leaving jacket 10 via conduit 25 may be suitably recovered or utilized.

According to one embodiment of this invention as illustrated with respect to Figs. 1 and 2, the vortex tube is employed in essentially one device and in combination with a pressure release valve. According to another embodiment of this invention the pressure release valve may be contained within a structure separate from that which contains the vortex tube and a conduit could connect the hot end of the vortex tube with a suitable heat exchange meansjor the pressure release valve.

This invention is of course not limited in use to an apparatus which operates intermittently. This invention 7 sure reducing or regulating device.

Many obvious changes in construction and design and other applications will be apparent and suggest themselves to those skilled in the art upon reading this disclosure without departing from the spirit or scope of this invention.

I claim:

1. A method for heating a pressure regulating device wherein a gas at a high pressure is passed therethrough to a lower pressure which comprises passing at least a portion of the high pressure gas passing through said pressure regulating device into a separation zone; separating in said zone said portion of high pressure gas into a high temperature gas stream and a low temperature gas stream; and passing said high temperature gas stream in heat exchange relationship with said pressure regulating device.

2. A method for preventing plugging of a pressure relief valve due to the formation of gas hydrates which com-- prises passing at least a portion of the gas released by said pressure relief valve into a separation zone; separatingin said zone said portion of the gas released by said pressure relief valve into a high temperature gas stream and a low temperature gas stream; and passing said high temperature gas stream in heat exchange relationship with said valve.

3. A pressure regulating device comprising in combination a valve body; a jacket in heat exchange relationship and in contact with at least a portion of said valve body; an inlet for said valve body and in communication with a source of gas at high pressure; a closure sealing ofl said inlet; a chamber above said closure; pressure responsive means within said chamber positioned to maintain said closure in position to seal ofi said inlet; a vortex tube having an inlet, a low temperature outlet and a high temperature outlet; a first conduit connecting said inlet of said vortex tube with said chamber; and a second conduit connecting the high temperature outlet of said vortex tube with said jacket.

4. A pressure regulating device comprising in combination a valve body; a heat exchange jacket surrounding said valve body; an inlet for said valve body; a chamber within said valve body with which said inlet communicates; a plug within said chamber positioned over said inlet; pressure responsive means Within said chamber and tending to keep said plug in position over said inlet; a vortex tube having an inlet, a low temperature outlet and a high temperature outlet; a first conduit connecting the inlet of said tube with said chamber; and a second conduit connecting the high temperature outlet of said tube with said jacket.

5. A pressure regulating device comprising in combination a valve body; a heat exchange jacket surrounding said valve body; a chamber within said valve body; an inlet to said chamber, a closure Within said chamber positioned over said inlet; a spring within said chamber bearing on one end against that portion of said chamber opposite said inlet and at the other end tending to keep said closure in position over said inlet; a vortex tube having an inlet, a low temperature outlet and a high temperature outlet; a first conduit connecting the inlet of said tube with said chamber; and a second conduit connecting the high temperature outlet of said tube with said jacket.

6. A pressure release apparatus comprising a pressure relief valve; a jacket surrounding said valve; a vortex tube in combination with said valve, said tube having an inlet, a low temperature outlet and a high temperature outlet; a first conduit connecting the inlet of said vortex tube with the interior of said valve; and a second conduit connecting the high temperature outlet of said vortex tube with said jacket.

7. An apparatus comprising a pressure regulating valve; a jacket in heat exchange relationship with at least a portion of said valve; a vortex tube in combination with said valve, said vortex tube having an inlet, a low temperature outlet and a high temperature outlet; a valve outlet conduit extending between said valve and the inlet of said vortex tube; and a conduit communicating the high temperature outlet of said vortex tube with said jacket.

References Cited in the file of this patent UNITED STATES PATENTS 1,321,343 Vuilleumier Nov. 11, 1919 1,952,281 Ranque Mar. 27, 1934 1,988,769 Aldridge et al. Jan. 22, 1935 2,520,302 Barnes Aug. 29, 1950 2,638,917 Clair May 19, 1953 FOREIGN PATENTS 166,542 Great Britain Jan. 5, 1922