1. The utility model provides a heat exchange tube automatic switch-over structure of gas phase reactor, includes casing (1), casing (1) both ends inner wall symmetry is fixed with first tube sheet (2) and second tube sheet (3), casing (1) both ends symmetry is fixed with distribution chamber (4), be fixed with a plurality of bracing pieces (5) between first tube sheet (2) and second tube sheet (3), be fixed with a plurality of baffling boards (6) on a plurality of bracing pieces (5), it is a plurality of baffling board (6) dislocation distribution, and one side and casing (1) inner wall laminating of baffling board (6), its characterized in that still includes:

the heat exchange tube comprises a heat exchange tube (7), a limiting cylinder (8), a first external thread cylinder (9) and a second external thread cylinder (10), wherein the inner wall of the heat exchange tube (7) is polygonal, the limiting cylinder (8) is fixed in the heat exchange tube (7), one end of the heat exchange tube (7) is fixedly provided with the first external thread cylinder (9) or the second external thread cylinder (10), and the rotating directions of the first external thread and the second external thread are opposite;

the supporting device comprises a first supporting plate (11) and a second supporting plate (12), wherein the first supporting plate (11) and the second supporting plate (12) are fixedly connected with a plurality of supporting rods (5), and threaded holes matched with first external threads or second external threads are formed in the first supporting plate (11) and the second supporting plate (12);

the dismounting device (13) is mainly used for mounting and dismounting the heat exchange tube (7) so as to realize the dismounting and replacement of a single heat exchange tube or a plurality of heat exchange tubes (7), and the dismounting device (13) is mounted between the first support plate (11) and the second support plate (12);

the driving device (14), the driving device (14) is mainly used for providing power for the dismounting device (13) so that the corresponding heat exchange tube (7) can be dismounted and mounted, and the driving device (14) is mounted between the first supporting plate (11) and the second supporting plate (12).

2. The automatic switching structure of a heat exchange tube of a gas phase reactor as claimed in claim 1, wherein: drive arrangement (14) are including connecting plate (15), the both ends of connecting plate (15) respectively with first backup pad (11) and second backup pad (12) fixed connection, be fixed with driving motor (16) on connecting plate (15), be fixed with first gear (17) on the output shaft of driving motor (16), rotate on the output shaft of driving motor (16) and be connected with fixed plate (18) with connecting plate (15) fixed connection, the meshing has second gear (19) on first gear (17), be fixed with first pivot (20) on second gear (19), the both ends of first pivot (20) are passed through the bearing and are rotated with first backup pad (11) and second backup pad (12) respectively and be connected, the symmetry is fixed with two third gears (21) on first pivot (20).

3. The automatic switching structure of a heat exchange tube of a gas phase reactor as claimed in claim 1, wherein: dismouting device (13) are including connecting cylinder (22), connecting cylinder (22) both ends inner wall symmetry is fixed with first spacing ring (23), connecting cylinder (22) both ends inner wall symmetry sliding connection has dismouting subassembly (24) that are used for heat exchange tube (7) to dismantle and install, first spring (25) have been cup jointed in connecting cylinder (22), the both ends of first spring (25) respectively with two dismouting subassembly (24) contact.

4. The automatic switching structure of a heat exchange tube of a gas phase reactor as claimed in claim 3, wherein: the dismounting component (24) comprises a transition pipe (26) which is connected with the first limit ring (23) in a sliding way, a second limiting ring (27) is fixed at one end of the transition pipe (26) positioned in the connecting cylinder (22), one end of the transition pipe (26) positioned in the connecting cylinder (22) is contacted with the first spring (25), the transition pipe (26) penetrates through the corresponding first support plate (11) or second support plate (12) in a sliding manner, one end of the transition pipe (26) far away from the connecting cylinder (22) is fixedly communicated with a polygonal pipe (28) matched with the inner wall of the heat exchange pipe (7), a connecting key (29) is fixed on the transition pipe (26), a driving component (30) for driving the transition pipe (26) to rotate is sleeved outside the transition pipe (26) in a sliding manner, and a limiting device (31) connected with the driving assembly (30) is fixed on the transition pipe (26).

5. The automatic switching structure of a heat exchange tube of a gas phase reactor as recited in claim 4, wherein: drive assembly (30) include support section of thick bamboo (32) with transition pipe (26) sliding sleeve, support section of thick bamboo (32) and fix on first backup pad (11) or second backup pad (12), ring channel (33) have been seted up on the outer wall of a support section of thick bamboo (32), the internal rotation of ring channel (33) is connected with fork arm (34), be fixed with fourth gear (35) on fork arm (34), fourth gear (35) are rotated with a transition section of thick bamboo and are connected, set up keyway (36) with connector key (29) looks adaptation on fourth gear (35).

6. The automatic switching structure of a heat exchange tube of a gas phase reactor as recited in claim 4, wherein: stop device (31) include spacing seat (37), set up blind hole (38) on fourth gear (35) and fix limiting plate (39) of keeping away from fourth gear (35) one end in connecting key (29), spacing seat (37) and transition pipe (26) fixed connection, blind hole (38) sliding connection has bolt (40), set up spout (41) with bolt (40) sliding connection on spacing seat (37), second spring (42) have been cup jointed in spout (41), the both ends of second spring (42) contact with inner wall and bolt (40) of spout (41) respectively, spacing hole (43) have been seted up on bolt (40), be fixed with on spacing seat (37) and run through spacing seat (37) and spacing hole (43) sliding connection's electronic round pin (44).

7. The automatic switching structure of a heat exchange tube of a gas phase reactor as recited in claim 6, wherein: the cross section of the bolt (40) is in a special shape, and a guide block (45) matched with the cross section of the bolt (40) is fixed on one side of the limiting seat (37) provided with the sliding groove (41).

8. The automatic switching structure of a heat exchange tube of a gas phase reactor as claimed in claim 1, wherein: the disassembly and assembly devices (13) are in meshing transmission through adjacent fourth gears (35), and the fourth gear (35) of one disassembly and assembly device (13) is meshed with the corresponding third gear (21).

Background

In the petrochemical industry, the heat exchanger is a heat exchange efficiency height, the equipment that the rate of utilization is wide, to large-scale equipment, the heat exchange tube in the heat exchanger, realize the cooling of thermal hot medium through the isolation between the two kinds of media of cold and hot, the installation that leads to the heat exchange tube on the corresponding tube sheet is very inconvenient with the maintenance installation usually to the both ends of the heat exchange tube of heat exchanger, need large-scale apparatus auxiliary erection, especially it is extremely inconvenient to the change of single heat exchange tube, need cut welded heat exchange tube, weld new heat exchange tube, complex operation, the degree of difficulty is great, influence work efficiency. Therefore, an automatic switching structure of the heat exchange tube of the gas phase reactor is provided.

Disclosure of Invention

The invention aims to provide an automatic switching structure of a heat exchange tube of a gas phase reactor, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a heat exchange tube automatic switching structure of a gas phase reactor comprises a shell, wherein a first tube plate and a second tube plate are symmetrically fixed on the inner walls of two ends of the shell, distribution chambers are symmetrically fixed on two ends of the shell, a plurality of support rods are fixed between the first tube plate and the second tube plate, a plurality of baffle plates are fixed on the plurality of support rods and are distributed in a staggered manner, one side of each baffle plate is attached to the inner wall of the shell, the heat exchange tube further comprises a heat exchange tube, a limiting cylinder, a first external thread cylinder, a second external thread cylinder, a first support plate, a second support plate, a plurality of dismounting devices and driving devices, the inner wall of the heat exchange tube is polygonal, the limiting cylinder is fixed in the heat exchange tube, a first external thread cylinder or a second external thread cylinder is fixed at one end of the heat exchange tube, the rotating directions of the first external thread and the second external thread are opposite, and the first support plate and the second support plate are fixedly connected with the plurality of support rods, offer the screw hole with first external screw thread or second external screw thread looks adaptation in first backup pad and the second backup pad, it is a plurality of dismouting device mainly used is to heat exchange tube installation and dismantlement, makes it can realize the dismantlement and the change of single or a plurality of heat exchange tubes, dismouting device installs between first backup pad and second backup pad, drive arrangement mainly used provides dismouting device power, makes it dismantle and install corresponding heat exchange tube, drive arrangement installs between first backup pad and second backup pad.

Preferably, drive arrangement includes the connecting plate, the both ends of connecting plate respectively with first backup pad and second backup pad fixed connection, be fixed with driving motor on the connecting plate, be fixed with first gear on driving motor's the output shaft, it is connected with the fixed plate with connecting plate fixed connection to rotate on driving motor's the output shaft, the meshing has the second gear on the first gear, be fixed with first pivot on the second gear, the both ends of first pivot are passed through the bearing and are rotated with first backup pad and second backup pad respectively and be connected, the symmetry is fixed with two third gears in the first pivot, and drive arrangement simple structure can effectual realization drive power transmit to dismouting device on, simple structure, the transmission is effectual.

Preferably, the dismouting device includes the connecting cylinder, connecting cylinder both ends inner wall symmetry is fixed with first spacing ring, connecting cylinder both ends inner wall symmetry sliding connection has the dismouting subassembly that is used for the heat exchange tube to dismantle with the installation, cup jointed first spring in the connecting cylinder, the both ends of first spring respectively with two the dismouting subassembly contact, first spring provide the power that resets for the dismouting subassembly, and the structure is ingenious, the dismantlement of the heat exchange tube of being convenient for.

Preferably, the disassembly and assembly component comprises a transition pipe in sliding connection with a first limiting ring, a second limiting ring is fixed at one end of the transition pipe, which is located in the connecting cylinder, the end of the transition pipe, which is located in the connecting cylinder, is in contact with the first spring, the transition pipe penetrates through the corresponding first supporting plate or second supporting plate in a sliding manner, a polygonal pipe matched with the inner wall of the heat exchange pipe is fixedly communicated with one end of the transition pipe, which is far away from the connecting cylinder, a connecting key is fixed on the transition pipe, a driving component for driving the transition pipe to rotate is sleeved outside the transition pipe in a sliding manner, a limiting device for connecting with the driving component is fixed on the transition pipe, and the disassembly and assembly of the heat exchange pipe is convenient.

Preferably, the drive assembly includes the support section of thick bamboo that cup joints with the transition pipe is slided, the support section of thick bamboo is fixed in first backup pad or second backup pad, the ring channel has been seted up on the outer wall of a support section of thick bamboo, the ring channel internal rotation is connected with the fork arm, be fixed with the fourth gear on the fork arm, the fourth gear rotates with a transition section of thick bamboo to be connected, set up on the fourth gear with the keyway of connecting key looks adaptation, realize the transmission between fourth gear and the transition pipe through the connecting key, the transmission is convenient.

Preferably, the limiting device comprises a limiting seat, a blind hole formed in the fourth gear and a limiting plate fixed at one end of the connecting key, which is far away from the fourth gear, the limiting seat is fixedly connected with the transition pipe, a bolt is connected in the blind hole in a sliding manner, a sliding chute in sliding connection with the bolt is formed in the limiting seat, a second spring is sleeved in the sliding chute, two ends of the second spring are respectively contacted with the inner wall of the sliding chute and the bolt, a limiting hole is formed in the bolt, an electric pin which penetrates through the limiting seat and is in sliding connection with the limiting hole is fixed on the limiting seat, the electric pin is inserted into the blind hole through the limiting device, the driving motor is driven to rotate reversely, the corresponding fourth gear rotates reversely, the rotation of the transition pipe is realized under the action of the bolt, the heat exchange pipe rotates reversely, the disassembly is realized, and simultaneously, the transition pipe is pushed to the corresponding position under the action of the first spring, the connecting key is matched with the key groove, so that the heat exchange tube can be better disassembled.

Preferably, the cross-section of bolt is heterotypic, prevents that the bolt from rotating in the spout, one side that spacing seat was equipped with the spout is fixed with the guide block with bolt cross-section looks adaptation, and the guide block makes the slip orbit of bolt more stable, avoids the bolt to rotate.

Preferably, a plurality of dismouting device is through adjacent fourth gear meshing transmission, and the fourth gear of one of them dismouting device and the third gear meshing that corresponds can realize drive arrangement to the provision of dismouting device power, can make mutual transmission between a plurality of dismouting devices again, and simple structure is convenient, and it is effectual to implement, improves work efficiency.

Compared with the prior art, the invention has the beneficial effects that:

the invention realizes the installation and the disassembly of a single heat exchange tube through the disassembly and assembly device, solves the problems that the single replacement of the traditional heat exchange tube is not changed and the tube plate needs to be cut, improves the working efficiency, can realize the installation and the replacement without welding and cutting the heat exchange tube by the disassembly and assembly device, has simple and convenient operation, ensures the requirements of different rotation directions of the installation and the disassembly threads of the corresponding heat exchange tube by the forward rotation and the reverse rotation of the driving motor in the driving device, and has flexible operation.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of the overall appearance structure of the present invention;

FIG. 3 is a schematic structural diagram of a driving device according to the present invention;

FIG. 4 is a schematic structural view of the disassembling device of the present invention;

FIG. 5 is a schematic view of a partial position relationship of the dismounting device of the present invention;

FIG. 6 is an enlarged view of area A of FIG. 3;

FIG. 7 is an enlarged view of area B of FIG. 4;

FIG. 8 is an enlarged view of area C of FIG. 4;

FIG. 9 is an enlarged view of area D of FIG. 4;

FIG. 10 is an enlarged view of area E in FIG. 4;

fig. 11 is an enlarged view of the region F in fig. 8.

In the figure: 1-a shell; 2-a first tubesheet; 3-a second tube sheet; 4-a distribution chamber; 5-a support rod; 6-baffle plate; 7-heat exchange tube; 8-a limiting cylinder; 9-a first externally threaded barrel; 10-a second externally threaded barrel; 11-a first support plate; 12-a second support plate; 13-a dismounting device; 14-a drive device; 15-a connecting plate; 16-a drive motor; 17-a first gear; 18-a fixed plate; 19-a second gear; 20-a first rotating shaft; 21-a third gear; 22-a connecting cylinder; 23-a first stop collar; 24-a disassembly and assembly; 25-a first spring; 26-a transition tube; 27-a second stop collar; 28-polygonal tube; 29-a connecting bond; 30-a drive assembly; 31-a limiting device; 32-a support cylinder; 33-an annular groove; 34-a fork arm; 35-a fourth gear; 36-a keyway; 37-a limiting seat; 38-blind hole; 39-limiting plate; 40-a bolt; 41-a chute; 42-a second spring; 43-a limiting hole; 44-an electric pin; 45-guide block.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-11, the present invention provides a technical solution: an automatic switching structure of a heat exchange tube of a gas phase reactor comprises a shell 1, wherein a first tube plate 2 and a second tube plate 3 are symmetrically fixed on the inner walls of two ends of the shell 1, a distribution chamber 4 is symmetrically fixed on two ends of the shell 1, a plurality of support rods 5 are fixed between the first tube plate 2 and the second tube plate 3, a plurality of baffle plates 6 are fixed on the plurality of support rods 5, the plurality of baffle plates 6 are distributed in a staggered manner, one side of each baffle plate 6 is attached to the inner wall of the shell 1, the automatic switching structure further comprises a heat exchange tube 7, a limiting cylinder 8, a first external thread cylinder 9, a second external thread cylinder 10, a first support plate 11, a second support plate 12, a plurality of dismounting devices 13 and a driving device 14, the inner wall of the heat exchange tube 7 is polygonal, the limiting cylinder 8 is fixed in the heat exchange tube 7, a first external thread cylinder 9 or a second external thread cylinder 10 is fixed at one end of the heat exchange tube 7, the first external thread and the second external thread have opposite rotation directions, first backup pad 11 and second backup pad 12 and a plurality of 5 fixed connection of bracing pieces, set up on first backup pad 11 and the second backup pad 12 with the screw hole of first external screw thread or second external screw thread looks adaptation, it is a plurality of dismouting device 13 mainly used is to heat exchange tube 7 installation and dismantlement, makes it can realize the dismantlement and the change of single or a plurality of heat exchange tube 7, dismouting device 13 is installed between first backup pad 11 and second backup pad 12, drive arrangement 14 mainly used provides dismouting device 13 power, makes it can dismantle and install corresponding heat exchange tube 7, drive arrangement 14 installs between first backup pad 11 and second backup pad 12.

Drive arrangement 14 includes connecting plate 15, the both ends of connecting plate 15 respectively with first backup pad 11 and second backup pad 12 fixed connection, be fixed with driving motor 16 on the connecting plate 15, be fixed with first gear 17 on driving motor 16's the output shaft, it is connected with fixed plate 18 with connecting plate 15 fixed connection to rotate on driving motor 16's the output shaft, the meshing has second gear 19 on the first gear 17, be fixed with first pivot 20 on the second gear 19, the both ends of first pivot 20 are passed through the bearing and are rotated with first backup pad 11 and second backup pad 12 respectively and be connected, the symmetry is fixed with two third gears 21 on the first pivot 20, and drive arrangement 14 simple structure can effectual realization drive power transmission to dismouting device 13 on, simple structure, the transmission is effectual.

Dismouting device 13 includes connecting cylinder 22, connecting cylinder 22 both ends inner wall symmetry is fixed with first spacing ring 23, connecting cylinder 22 both ends inner wall symmetry sliding connection has the dismouting subassembly 24 that is used for heat exchange tube 7 to dismantle and installs, cup jointed first spring 25 in connecting cylinder 22, first spring 25's both ends respectively with two dismouting subassembly 24 contact, first spring 25 provides the power that resets for dismouting subassembly 24, and the structure is ingenious, the dismantlement of the heat exchange tube 7 of being convenient for.

The dismounting and mounting assembly 24 comprises a transition pipe 26 connected with the first limiting ring 23 in a sliding manner, a second limiting ring 27 is fixed at one end of the transition pipe 26 located in the connecting cylinder 22, one end of the transition pipe 26 located in the connecting cylinder 22 is in contact with the first spring 25, the transition pipe 26 penetrates through the corresponding first support plate 11 or second support plate 12 in a sliding manner, a polygonal pipe 28 matched with the inner wall of the heat exchange pipe 7 is fixedly communicated with one end of the transition pipe 26 far away from the connecting cylinder 22, a connecting key 29 is fixed on the transition pipe 26, a driving assembly 30 used for driving the transition pipe 26 to rotate is sleeved outside the transition pipe 26 in a sliding manner, a limiting device 31 used for being connected with the driving assembly 30 is fixed on the transition pipe 26, and the heat exchange pipe 7 is convenient to dismount through the dismounting and mounting assembly 24.

Drive assembly 30 includes the support section of thick bamboo 32 that cup joints with transition pipe 26 slides, support a section of thick bamboo 32 and fix on first backup pad 11 or second backup pad 12, ring channel 33 has been seted up on the outer wall of a support section of thick bamboo 32, ring channel 33 internal rotation is connected with fork arm 34, be fixed with fourth gear 35 on the fork arm 34, fourth gear 35 rotates with a transition section of thick bamboo to be connected, set up on the fourth gear 35 with the keyway 36 of connecting key 29 looks adaptation, realize the transmission between fourth gear 35 and the transition pipe 26 through connecting key 29, the transmission is convenient.

The limiting device 31 comprises a limiting seat 37, a blind hole 38 arranged on the fourth gear 35 and a limiting plate 39 fixed at one end of the connecting key 29 far away from the fourth gear 35, the limiting seat 37 is fixedly connected with the transition pipe 26, a bolt 40 is slidably connected in the blind hole 38, a chute 41 slidably connected with the bolt 40 is arranged on the limiting seat 37, a second spring 42 is sleeved in the chute 41, two ends of the second spring 42 are respectively contacted with the inner wall of the chute 41 and the bolt 40, a limiting hole 43 is arranged on the bolt 40, an electric pin 44 slidably connected with the limiting hole 43 through the limiting seat 37 is fixed on the limiting seat 37, the bolt 40 is inserted into the blind hole 38 through the limiting device 31, the driving motor 16 is driven to rotate reversely, the corresponding fourth gear 35 rotates reversely, the rotation of the transition pipe 26 is realized under the action of the bolt 40, the heat exchange pipe 7 rotates reversely, and the disassembly is realized, meanwhile, under the action of the first spring 25, the transition pipe 26 is pushed to the corresponding position, so that the connecting key 29 is matched with the key groove 36, and the heat exchange pipe 7 can be better removed.

The cross-section of bolt 40 is heterotypic, prevents that bolt 40 from rotating in spout 41, the one side that spacing seat 37 was equipped with spout 41 is fixed with the guide block 45 with bolt 40 cross-section looks adaptation, and guide block 45 makes the slip orbit of bolt 40 more stable, avoids bolt 40 to rotate.

A plurality of dismouting device 13 is through the meshing transmission of adjacent fourth gear 35, and the fourth gear 35 of one of them dismouting device 13 meshes with corresponding third gear 21, can realize drive arrangement 14 to the provision of dismouting device 13 power, can make mutual transmission between a plurality of dismouting device 13 again, and simple structure is convenient, implements effectually, improves work efficiency.

In this scheme, the installation theory of operation of single heat exchange tube 7: when the heat exchange tube 7 is inserted into the polygonal tube 28, the driving device 14 is started to drive the fourth gear 35 to rotate, under the action of the connecting key 29, the transition pipe 26 rotates, and then the polygonal pipe 28 rotates, meanwhile, when polygonal tubes 28 rotate, heat exchange tubes 7 are driven to rotate and slide on polygonal tubes 28, when the limiting cylinder 8 in the heat exchange tube 7 is in contact with the multi-change tube, the corresponding first external thread or second external thread on the heat exchange tube 7 is screwed on the corresponding first supporting plate 11 or second supporting plate 12, at this time, under the action of the limiting cylinder 8, the polygonal tube 28 is pushed to move, the transition tube 26 is driven to slide on the fourth gear 35 until the connecting key 29 is separated from the fourth gear 35, at this time, the latch 40 is disengaged from the blind hole 38 of the fourth gear 35, and when the connecting key 29 is completely disengaged, the heat exchange tube 7 is mounted.

In the scheme, the working principle of disassembling a single heat exchange tube 7 is that, during disassembling, firstly, the limit of an electric pin 44 is removed, under the action of a second spring 42, a bolt 40 is ejected out of a chute 41 of a limit seat 37, so that one end of the bolt 40 is abutted against one side of a fourth gear 35, a driving device 14 is started, the fourth gear 35 rotates until the bolt 40 is inserted into a blind hole 38 of the fourth gear 35, the bolt 40 drives a transition tube 26 to rotate, further drives a polygonal tube 28 to rotate, and simultaneously drives a corresponding heat exchange tube 7 to rotate, so that the heat exchange tube 7 rotates out, meanwhile, under the action of a first spring 25, the transition tube 26 slides in the fourth gear 35, slides into a key groove 36 through a corresponding connecting key 29, so that the transmission between the fourth gear 35 and the transition tube 26 is more effective, the transmission effect is better, until a corresponding first external thread cylinder 9 or second external thread cylinder 10 on the heat exchange tube 7 rotates out, the disassembly of the heat exchange tube 7 is realized.

In the scheme, the driving device 14 works on the principle that the driving motor 16 is started to drive the first gear 17 to rotate, so as to drive the second gear 19 to rotate, and simultaneously drive the third gear 21 to rotate through the first rotating shaft 20, and further drive the dismounting device 13 to rotate through the meshing of the third gear 21 and the fourth gear 35, so as to provide power for the dismounting device 13.

In the scheme, the drive motor 16 is preferably of a Y80M1-2 model, the motor is supplied by mains supply, the motor operation circuit is a normal and reverse rotation control program of a conventional motor, the circuit operation is a conventional circuit, the circuits and the control related to the scheme are the prior art, and too much description is omitted herein.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.