US2007363A - Pressure regulator - Google Patents

Pressure regulator Download PDF

Info

Publication number
US2007363A
US2007363A US63554032A US2007363A US 2007363 A US2007363 A US 2007363A US 63554032 A US63554032 A US 63554032A US 2007363 A US2007363 A US 2007363A
Authority
US
United States
Prior art keywords
bellows
valve
pressure
casing
plug
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Boynton Alexander
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CHAS A BEATTY
Original Assignee
CHAS A BEATTY
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by CHAS A BEATTY filed Critical CHAS A BEATTY
Priority to US63554032 priority Critical patent/US2007363A/en
Application granted granted Critical
Publication of US2007363A publication Critical patent/US2007363A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D16/00Control of fluid pressure
    • G05D16/04Control of fluid pressure without auxiliary power
    • G05D16/06Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule
    • G05D16/0616Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a bellow
    • G05D16/0619Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a bellow acting directly on the obturator
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/7722Line condition change responsive valves
    • Y10T137/7781With separate connected fluid reactor surface
    • Y10T137/7793With opening bias [e.g., pressure regulator]
    • Y10T137/7809Reactor surface separated by apertured partition
    • Y10T137/7812Valve stem passes through the aperture
    • Y10T137/7813Plural reactor surfaces

Definitions

  • My invention relates to pressure regulators and has particular reference to regulators for providing a uniform pressure within a fluid conducting line or container.
  • Another object of the invention is to provide a device of this character which is simple in construction and which will not easily get out of order in use.
  • I further desire to provide a structure of this character which may be set for pressures of different value and which will be capable of operation under both high and low pressures on the intake side and be capable of adjustment to accommodate the particular pressure which is to be permitted on the discharge side.
  • Fig. 1 is a central longitudinal section through a conducting line having my invention installed therein.
  • Fig. 2 is a similar sectional view through the inlet end of said device, said view being taken at right angles to the view shown in Fig. 1.
  • Fig. 3 is a transverse section on the plane 3--3 of Fig. l;
  • Fig. 4 is a. similar transverse section on the 40 plane 4-4 of Fig. 2.
  • my device in the drawing I have shown my device as being installed within a housing I6, which forms a part of a conducting line.
  • the upper end of the housing is connected with a T-shaped fitting I5, hav- I9 to the discharge flow line 20.
  • the upper end ing a lateral port connected by means of the L i which is fitted a washer 2
  • the stem 4 has a handle at its outer end whereby it may be rotated. Its inner end projects through the plug and is formed with a squared head 4a fitting wit-hin a socket 22 in the nipple 6 upon the valve adjusting assembly. 'I'he squared head 4a is slidable within the socket 22 and, by the rotation thereof, the nipple may be screwed into or from a threaded connection at 23 with the valve carrier I2.
  • the valve carrier I2 is an elongated sleeve, which has at its lower end a diametrical cross arm 24, which is adapted to t slidably between two upright arms 25 upon the valve seat member I3.
  • the cross arm has a threaded opening axially of the sleeve I2 to receive the shank 2B of the valve II, which projects downwardly from the cross arm.
  • the expanding bellows 21 which forms a closed diaphragm adapted by its expansion and contraction to regulate the position of the valve.
  • the bellows member shown is made up of a wall of thin resilient metal, which is preferably a two or three-ply wall, for the reason that this construction is somewhat more compressible and more durable than a single ply wall.
  • the metal making up the bellows is strong resilient metaL, I have shown the corrugations on the wall of the bellows as extending spirally around the wall of the tube which constitutes the bellows. This form is employed for the purposes of economy, it being also common to employ -bellows made up of ringshaped corrugations.
  • Said member is a circular disc with the downwardly projecting flange thereon previously mentioned. It also has a central inwardly extending boss to accommodate a threaded socket 28 to receive the lower threaded end of the screw IIJ.
  • the screw I0 has its head projecting upwardly into the squared socket 22, the said head projecting very slightly above the .wall which closes the inner end of said socket. It has an enlarged upper end, which has a slight clearance relative to the wall of the socket and has a shoulder bearing against the upper end of the connecting member 1. It is to be noted that, when the shoulder is in contact with the connecting member, the head of the screw has a slight clearance above the wall of the socket, thus forming a swivel connection between the connecting member l and the valve adjusting plug or nipple i. In this way it is possible to screw the plug or nipple, upwardly or downwardly in the sleeve I2 to ad- :lust the valve, without the necessity of rotating the bellows member.
  • the lower end of the bellows is also connected by welding or soldering to an upwardly extending ilange 2! upon the bottom end connection I for the bellows.
  • the said bottom connecting member' is of annular shape and is threaded at its lower end to receive the base connection 3l.
  • Said base connection is a plug-shaped nut having a lower threaded shank 9 for engagement with the arms upon the base holder I3.
  • a spiral spring Il Within the bellows, and compressed slightly between the upper and lower end connections, is a spiral spring Il. 'Ihis spring tends to hold the bellows in a predetermined extended position, as will be later described.
  • The-valve seat member I3 has a lower ring shaped end threaded on its outer surface to screw within the inner wall oi-the casing Ii. It has countersimk openings 33 on its lower side to accommodate a wrench, by means of which it may be screwed in position with the arms 25 thereon extending upwardly into the sleeve l2. As will be seen from Fig. 4, the two arms 25 are circular on their outer side-to iit within the sleeve and have a diametrical slot between them to receive the transverse connecting arms 2l upon the sleeve I2.
  • valve seat member I! I employs a lock nut Il adapted to compress a washer Il against the lower end of the valve seat member and to lock the same from unscrewing.
  • the opening through the nut' is formed with a stream line contour to accommodate iluid in toward the valve.
  • the pressure will then be released and the spring will again extend the bellows, but not quite to its original extent, there being a small permanent set developed in the bellows, due to its compression.
  • the spring will be under slightly more tension than it was before the compression.
  • the plug after being 'tightened in position will be soldered in place and the passage 3
  • the plug may, however, be tightened and soldered before the bellows is allowed to expand. In such case a vacuum will result above ⁇ the glycerine.
  • the handle 4 When the device is to be operated the handle 4 will be u ⁇ sed to screw the bellows assembly up or down as is necessary to adjust the valve il to the proper position to allow suiiicient gas to enter to maintain the desired pressure in the casing. Thereafter, the operation of the device will be automatic. Ii the pressure in the line increases unduly the effect will be to compress the diaphragm or bellows member longitudinally and as the lower end is anchored in position the upper end will be drawn downwardly, forcing the sleeve I2, with the valve thereon, downwardly also so as to move the valve toward closed position and to constrict the passage through which the iluid is entering. By thus restricting the passage of the iluid the pressure inside wil.
  • My device is adapted particularly for use in handling gas and to preserve in .a branch line a pressure which may be materially lower than that in the main line.
  • a pressure which may be materially lower than that in the main line.
  • This may be employed, for example, in a line running from a gas well, where the pressure is high, to a gas main from which gas is consumed.
  • the pressure in the main line may be preserved at a value considerably lower than that from the well.
  • thejpressure may be stepped down between any two conducting lines or containers so that the proper pressure may be had in the line oi the consumer, whether in industrial establishments or for home consumption. It will ilnd a general application in many dinerent lines conveying gases or liquids.
  • my device will control pressures in the conducting line so that they will be maintained within a certain maximum pressure which may be pre- ⁇ determined.
  • the device is simple in construction and will not easily get out of order.
  • the further advantages of the device will be obvious to .site end of said support, said valve being fautomatically adjustable by the longitudinal movement of said support in response to the pressure of iiuid passing through said casing to maintain a predetermined fluid pressure in said casing.
  • a pressure regulator including a casing hav-- ing an inlet and an outlet for iiuid under pressure
  • a pressure regulator including a casing having an inlet and an outlet for fluid under pressure
  • a bellows-shaped support at one end of said support projecting into said inlet, means to yieldably hold said support in extended position
  • liquid means to prevent excessive collapsing movement of said support under uid pressure and means to anchor the end of said support adjacent said valve, the walls of said support being compressible under fluid pressure in said casing to move said valve relative to said inlet.
  • a valve control device for pressure regulators including a uniformly corrugated bellows of metal, means to seal the ends thereof, a spring within said bellows tending to hold said bellows extended, means to anchor one end of said bellows, a valve on said bellows adjacent said anchor controlled through the, movement of said bellows, and means to prevent undue collapsing of said bellows, comprising a liquid nearly illlin the interior of said bellows but leaving an air space therein when said bellows is normally operating.
  • a pressure regulator including a casing through which iluid under pressure may ow, an inlet thereto, a bellowsshaped metal support, a valve thereon controlling said inlet, a spring to hold said bellows extended to close said valve, a charge of liquid sealed in said bellows, and means to anchor one end of said bellows in said casing.
  • a pressure regulator including, a an inlet to said casing, a valve seat in said inlet, a sleeve in said casing. a longitudinally compressible diaphragm in said sleeve, a longitudinally adjustable plug in said sleeve, a swivel engagevment between said plug and said diaphragm, and
  • a pressure regulator including, a casing, an inlet to said casing, a valve seat in said inlet, a

Description

A. BOYNTON PRESSURE REGULATOR Filed Sept. 50, 1932 Alexander` Boynton ma July 9, 1935.
Patented July 9, 1935 PATENT OFFICE PRESSURE REGULATOR Alexander Boynton, San Antonio, Tex., assignor to Chas. A. Beatty, San Antonio, Tex.
Application September 30, 1932, Serial No. 635,540
7 Claims.
My invention relates to pressure regulators and has particular reference to regulators for providing a uniform pressure within a fluid conducting line or container.
It is an object of the invention to provide an automatically operating device by means of which a control valve may be moved to allow the entrance to a line or container of a certain maximum fluid pressure.
I desire to provide a device of this character which will operate accurately and which will be sensitive to changes in pressure and which will be enabled to adapt itself to changes in pressure so as to maintain the pressure uniform in the device and its discharge pipe.
Another object of the invention is to provide a device of this character which is simple in construction and which will not easily get out of order in use.
I further desire to provide a structure of this character which may be set for pressures of different value and which will be capable of operation under both high and low pressures on the intake side and be capable of adjustment to accommodate the particular pressure which is to be permitted on the discharge side.
The invention resides in the particular construction and arrangement of the parts making up the invention, all of which will be more clearly understood from the description which follows:
In the drawing herewith, Fig. 1 is a central longitudinal section through a conducting line having my invention installed therein.
Fig. 2 is a similar sectional view through the inlet end of said device, said view being taken at right angles to the view shown in Fig. 1.
Fig. 3 is a transverse section on the plane 3--3 of Fig. l; and
Fig. 4 is a. similar transverse section on the 40 plane 4-4 of Fig. 2.
In the drawing I have shown my device as being installed within a housing I6, which forms a part of a conducting line. The upper end of the housing is connected with a T-shaped fitting I5, hav- I9 to the discharge flow line 20. The upper end ing a lateral port connected by means of the L i which is fitted a washer 2|, which may be of compressible material such as lead forming a seal around the threaded connection between the plug and the T-shaped fitting.
The stem 4 has a handle at its outer end whereby it may be rotated. Its inner end projects through the plug and is formed with a squared head 4a fitting wit-hin a socket 22 in the nipple 6 upon the valve adjusting assembly. 'I'he squared head 4a is slidable within the socket 22 and, by the rotation thereof, the nipple may be screwed into or from a threaded connection at 23 with the valve carrier I2.
The valve carrier I2 is an elongated sleeve, which has at its lower end a diametrical cross arm 24, which is adapted to t slidably between two upright arms 25 upon the valve seat member I3. The cross arm has a threaded opening axially of the sleeve I2 to receive the shank 2B of the valve II, which projects downwardly from the cross arm.
With the housing formed by the sleeve I2 is the expanding bellows 21, which forms a closed diaphragm adapted by its expansion and contraction to regulate the position of the valve. The bellows member shown is made up of a wall of thin resilient metal, which is preferably a two or three-ply wall, for the reason that this construction is somewhat more compressible and more durable than a single ply wall. The metal making up the bellows is strong resilient metaL, I have shown the corrugations on the wall of the bellows as extending spirally around the wall of the tube which constitutes the bellows. This form is employed for the purposes of economy, it being also common to employ -bellows made up of ringshaped corrugations.
The upper end of the belows is connected by welding or soldering to the flange upon the connecting member I. Said member is a circular disc with the downwardly projecting flange thereon previously mentioned. It also has a central inwardly extending boss to accommodate a threaded socket 28 to receive the lower threaded end of the screw IIJ.
The screw I0 has its head projecting upwardly into the squared socket 22, the said head projecting very slightly above the .wall which closes the inner end of said socket. It has an enlarged upper end, which has a slight clearance relative to the wall of the socket and has a shoulder bearing against the upper end of the connecting member 1. It is to be noted that, when the shoulder is in contact with the connecting member, the head of the screw has a slight clearance above the wall of the socket, thus forming a swivel connection between the connecting member l and the valve adjusting plug or nipple i. In this way it is possible to screw the plug or nipple, upwardly or downwardly in the sleeve I2 to ad- :lust the valve, without the necessity of rotating the bellows member.
The lower end of the bellows is also connected by welding or soldering to an upwardly extending ilange 2! upon the bottom end connection I for the bellows. The said bottom connecting member'is of annular shape and is threaded at its lower end to receive the base connection 3l. Said base connection is a plug-shaped nut having a lower threaded shank 9 for engagement with the arms upon the base holder I3. There is a'small channel or duct, shown at 3l, formed in the upper end of this plug to allow the passage of liquid from the interior of the bellows. It is my intention to connect the plug rigidly in position when the device has been assembled and Y to connect the plug with the bottom end connection l by means ot solder or welding material shown at I2.
Within the bellows, and compressed slightly between the upper and lower end connections, is a spiral spring Il. 'Ihis spring tends to hold the bellows in a predetermined extended position, as will be later described.
The-valve seat member I3 has a lower ring shaped end threaded on its outer surface to screw within the inner wall oi-the casing Ii. It has countersimk openings 33 on its lower side to accommodate a wrench, by means of which it may be screwed in position with the arms 25 thereon extending upwardly into the sleeve l2. As will be seen from Fig. 4, the two arms 25 are circular on their outer side-to iit within the sleeve and have a diametrical slot between them to receive the transverse connecting arms 2l upon the sleeve I2. 'I'he upper ends oi the arms abut against the lower side oi the plug 30 and ,are threaded to receive the lower shank 9 on said plug. It will be seen that this connection has the eilect of anchoring the lower end of the bellows member to the lower end of the casing Ii oi' the now line. Furthermore, the sleeve i2 is held against rotation relative thereto so that the upper. valve-adjusting plug t may be adjusted. The ring Il has a e axially therethrough, the inner side of which is rounded to form a seat for the valve Il. The passage through the ringistheinlet ioriiuid suchasgas through the casing.
Below the valve seat member I! I. employ a lock nut Il adapted to compress a washer Il against the lower end of the valve seat member and to lock the same from unscrewing. The opening through the nut'is formed with a stream line contour to accommodate iluid in toward the valve. i
' I may place a pressure indicator I5 of ordinary construction upon the upper T IVI ot the.
apreasure thereon.
Thebellowswihbeassembledbyturningthe lower end thereof upwardly before the plug 3l basbeenscrewedlnpition. Thespringwillbe inserted in place and the bellows will then be illled with a liquid such as glycerine. After being thus illled, the bellows will be compressed longitudinally to the maximum amount which it is contemplated it will be compressed in use. This will force some of the glycerine out through the passage 3|. The pressure will then be released and the spring will again extend the bellows, but not quite to its original extent, there being a small permanent set developed in the bellows, due to its compression. The spring will be under slightly more tension than it was before the compression. The plug after being 'tightened in position will be soldered in place and the passage 3| for the g/lycerine will be closed. It will thus be seen that during operation the interior of the bellows member will be nearly iilled with glycerine, the remaining portion being illled with air. The plug may, however, be tightened and soldered before the bellows is allowed to expand. In such case a vacuum will result above` the glycerine.
When the device is to be operated the handle 4 will be u`sed to screw the bellows assembly up or down as is necessary to adjust the valve il to the proper position to allow suiiicient gas to enter to maintain the desired pressure in the casing. Thereafter, the operation of the device will be automatic. Ii the pressure in the line increases unduly the effect will be to compress the diaphragm or bellows member longitudinally and as the lower end is anchored in position the upper end will be drawn downwardly, forcing the sleeve I2, with the valve thereon, downwardly also so as to move the valve toward closed position and to constrict the passage through which the iluid is entering. By thus restricting the passage of the iluid the pressure inside wil. be decreased and the predetermined pressure within the casing will be maintained. It is obvious that if the reverse condition was set up in the causing, that is, ii the pressure was lowered therein beyond the desired amount, the result would be to allow the bellows to expand slightly with a result that the valve would be opened to allow the entrance of a larger proportion of the pressure fluid.
My device is adapted particularly for use in handling gas and to preserve in .a branch line a pressure which may be materially lower than that in the main line. This may be employed, for example, in a line running from a gas well, where the pressure is high, to a gas main from which gas is consumed. The pressure in the main line may be preserved at a value considerably lower than that from the well. It will be obvious that thejpressure may be stepped down between any two conducting lines or containers so that the proper pressure may be had in the line oi the consumer, whether in industrial establishments or for home consumption. It will ilnd a general application in many dinerent lines conveying gases or liquids.
By employing a liquid, such as glycerine, within the bellows member during its operation, I am enabled to handle what would ordinarily be considered excessively highpressures. The presence of the liquid within the bellows or diaphragm will prevent its collapsing under extreme pressure. The amount oi compression oi the bellowswillbelimitedbythelengthoitheair pocket or vacuum, as the case may be, above the liquid remaining in the bellows, which will ordinarily be small, compared to the total length cttbebellows. Iamenabledtohandlepresdraulic pressures to the amount of ten thousand pounds per square inch have` been handled without impairing the apparatus. A
It will be 'obvious' that the arrangement of my apparatus will permit the control o1' pressures in lines with a high degree of accuracy and that when once properly set and calibrated,
. my device will control pressures in the conducting line so that they will be maintained within a certain maximum pressure which may be pre-` determined. The device is simple in construction and will not easily get out of order. The further advantages of the device will be obvious to .site end of said support, said valve being fautomatically adjustable by the longitudinal movement of said support in response to the pressure of iiuid passing through said casing to maintain a predetermined fluid pressure in said casing.
2. A pressure regulator including a casing hav-- ing an inlet and an outlet for iiuid under pressure,
.a bellows-shaped support, a valve at `one end-of said support projecting into said inlet, means to yieldably hold said support in extended position and means to anchor the end of said support adjacent said valve, the walls of said support being compressible under uid 'pressure in said casing to move said valve relative to said inlet. 3. A pressure regulator including a casing having an inlet and an outlet for fluid under pressure,
, a bellows-shaped support, a valve at one end of said support projecting into said inlet, means to yieldably hold said support in extended position,
liquid means to prevent excessive collapsing movement of said support under uid pressure, and means to anchor the end of said support adjacent said valve, the walls of said support being compressible under fluid pressure in said casing to move said valve relative to said inlet.
4. A valve control device for pressure regulators including a uniformly corrugated bellows of metal, means to seal the ends thereof, a spring within said bellows tending to hold said bellows extended, means to anchor one end of said bellows, a valve on said bellows adjacent said anchor controlled through the, movement of said bellows, and means to prevent undue collapsing of said bellows, comprising a liquid nearly illlin the interior of said bellows but leaving an air space therein when said bellows is normally operating.
5. A pressure regulator including a casing through which iluid under pressure may ow, an inlet thereto, a bellowsshaped metal support, a valve thereon controlling said inlet, a spring to hold said bellows extended to close said valve, a charge of liquid sealed in said bellows, and means to anchor one end of said bellows in said casing. l
6. A pressure regulator including, a an inlet to said casing, a valve seat in said inlet, a sleeve in said casing. a longitudinally compressible diaphragm in said sleeve, a longitudinally adjustable plug in said sleeve, a swivel engagevment between said plug and said diaphragm, and
a valve at the other end of said diaphragm adjacent said seat, said diaphragmbeing compressible in response to fluid pressure in said casing to con-4 trol the position of said valve.
'7. A pressure regulator including, a casing, an inlet to said casing, a valve seat in said inlet, a
'sleeve in said casing, a longitudinally compressible diaphragm in said sleeve, means to support said diaphragm at the upper end of said sleeve, and a valve atthe other end of said diaphragm adjacent said seat, said diaphragm being compressible in response to fluid pressure in said casing to control the position o! said valve.
` ALEXANDER BOYNTON.
US63554032 1932-09-30 1932-09-30 Pressure regulator Expired - Lifetime US2007363A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US63554032 US2007363A (en) 1932-09-30 1932-09-30 Pressure regulator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US63554032 US2007363A (en) 1932-09-30 1932-09-30 Pressure regulator

Publications (1)

Publication Number Publication Date
US2007363A true US2007363A (en) 1935-07-09

Family

ID=24548191

Family Applications (1)

Application Number Title Priority Date Filing Date
US63554032 Expired - Lifetime US2007363A (en) 1932-09-30 1932-09-30 Pressure regulator

Country Status (1)

Country Link
US (1) US2007363A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2556867A (en) * 1946-03-29 1951-06-12 Carlisle Willis Calvert Flow valve
US2867121A (en) * 1954-05-17 1959-01-06 Statham Instrument Inc Pressure transducer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2556867A (en) * 1946-03-29 1951-06-12 Carlisle Willis Calvert Flow valve
US2867121A (en) * 1954-05-17 1959-01-06 Statham Instrument Inc Pressure transducer

Similar Documents

Publication Publication Date Title
US2518625A (en) Flow bean
US2619122A (en) Flow regulator and float valve assembly
US2587212A (en) Relief valve
US2685891A (en) Automatic fluid control means
US2364812A (en) Poppet valve
US2955614A (en) Constant tubing pressure choke
US4077425A (en) Fluid flow control devices
US2354283A (en) Antibuzz fluid pressure regulator
US2007363A (en) Pressure regulator
US2882007A (en) Fluid pressure operated valve
US2439336A (en) Thermostatic valve
US2543203A (en) Pressure regulator
US4100933A (en) Fire protection water supply valve
US2895501A (en) Pressure regulator construction
US2869575A (en) Fluid pressure regulator
US2100997A (en) Pressure control device
US2038013A (en) Regulating valve
US2044452A (en) Adjustable loading means
US2371830A (en) Combined stop and float valve
US1399013A (en) Pressure-regulator
US1457937A (en) Pressure-regulating valve
US2786645A (en) Line seating conical valves
US2591148A (en) Pressure responsive valve
US2989081A (en) Ball cock valves
US2249101A (en) Refrigerating apparatus