Electromagnetic emergency cut-off valve
By adopting a ball valve structure and a torsion spring mechanical structure in the solenoid gas emergency shutoff valve, combined with the solenoid core assembly and the switch plate, the problems of flow loss, poor aesthetics and inaccurate feedback of the valve closing status in the prior art are solved, and the effects of rapid automatic valve closing and accurate state feedback are achieved.
Patent Information
- Application Number
- CN202421952813.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-13
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2034-08-13
AI Technical Summary
The existing solenoid gas emergency shutoff valves have problems such as flow loss, poor aesthetics and inaccurate feedback on the valve closing status, especially in emergency situations, when the valve is closed for a long time.
Using ball valve structure and torsion spring mechanical structure, the drive pins to engage or extrude through the solenoid core assembly to achieve the fast valve opening and closing function, and provide accurate valve closing signal through the switch plate.
It realizes automatic quick valve closing in emergency situations, ensuring large flow and valve closing time within 1 second, while providing accurate feedback on and off valve status.
Smart Images
Figure CN222823750U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of cut-off valves, and particularly relates to an electromagnetic emergency cut-off valve. Background Art
[0002] At present, electromagnetic gas emergency shut-off valves mostly use a stop valve structure. Since the stop valve airway is in the shape of a "J", the air flow inside turns several times, the flow is easily lost, and the flow rate is small.
[0003] Traditional solenoid valves obtain power and valve closing signals mostly through wires connected to combustible gas detectors, and the connected wires affect the appearance.
[0004] Traditional solenoid valves do not have valve closing status feedback, so when the detector sends a signal to the solenoid valve to close the valve, it is not possible to accurately know whether the valve is open or closed.
[0005] There are motor-driven ball valves on the market. The motor increases the torque through gear reduction to determine the ball valve opening and closing. Due to the increase of the deceleration structure, the actual closing time is longer when the valve is closed after receiving the command. The closing time of the household emergency shut-off valve is 1 second. After adding the deceleration mechanism, the closing time increases to several seconds or even longer. Utility Model Content
[0006] In order to solve the above problems existing in the prior art, the purpose of the utility model is to provide an electromagnetic emergency shut-off valve which can automatically close the valve and has a short closing time.
[0007] The technical solution adopted by the utility model is:
[0008] An electromagnetic emergency shut-off valve comprises a top shell, the lower part of which is connected to a valve body, a steering shaft is installed inside the top shell, the lower end of the rotating shaft is connected to a valve stem, the lower end of the valve stem is connected to a ball, the ball is arranged in the valve body, and a through hole is arranged on the ball; a torsion spring is connected between the steering shaft and the valve body, and a slot is arranged on the steering shaft; and an electromagnetic core assembly is also included, a latch is connected inside the electromagnetic core assembly, and one end of the latch is inserted into the slot.
[0009] The torsion spring of the utility model is connected between the steering shaft and the valve body. In the valve opening state, the torsion spring has been twisted by a certain angle compared to the initial position, and the torsion spring is twisted to have a restoring force. In the valve opening state, the electromagnetic core assembly drives the latch to engage in the slot, offsetting the restoring force of the torsion spring, so that the cut-off valve remains in the valve opening state. In an emergency, the equipment receives a valve closing signal, the driving force of the electromagnetic core assembly on the latch disappears, and under the restoring force of the torsion spring, the steering shaft rotates, and the latch is squeezed out of the slot, and the steering shaft continues to rotate to the valve closing state.
[0010] In summary, the cut-off valve of the utility model can automatically close the valve in an emergency situation to achieve automatic control.
[0011] The utility model uses a mechanical structure to drive the mechanical structure to pre-tighten the torsion spring through electromagnetic force when the valve is opened. After receiving the valve closing instruction, the electromagnetic force disappears and drives the mechanical structure to release the torsion spring to drive the ball valve to rotate and close the valve. The valve closing time can be within 1 second.
[0012] The valve closing gas circuit of the utility model adopts a ball valve structure, and the gas passage is an "I"-shaped gas circuit, which is convenient for air flow to pass through and has a large flow rate. In actual application tests, the flow rate of the ball valve is 50% larger than that of the stop valve.
[0013] When the ball valve rotates to close, the switch pressure piece touches the travel switch on the circuit board, providing an accurate valve closing signal, which is then transmitted to the control platform, so that it can accurately know whether the shut-off valve is in the open or closed state.
[0014] As a preferred embodiment of the utility model, the electromagnet core assembly also includes an electromagnet core shell, a moving iron core is sleeved in the electromagnet core shell, a latch is fixed to the moving iron core, a permanent magnet and a fixed iron core are also fixed in the electromagnet core shell, and an enameled coil is sleeved outside the fixed iron core; when the enameled coil is not energized, the permanent magnet generates a magnetic force to attract the moving iron core and the fixed iron core together; when the enameled coil is energized, the fixed iron core generates a magnetic force in the opposite direction to the permanent magnet, and the moving iron core is no longer subject to the magnetic attraction force of the fixed iron core.
[0015] As a preferred solution of the utility model, a limiting step is provided on the latch, and the latch sleeve is arranged on the electromagnet core housing, and the electromagnet core housing blocks the limiting step.
[0016] As a preferred solution of the utility model, the top shell is connected to an outer shell, the electromagnet core assembly is arranged in the outer shell, a circuit board is also arranged in the outer shell, and the circuit board is electrically connected to the enameled coil.
[0017] As a preferred solution of the utility model, a travel switch is arranged on the circuit board, and a switch pressing piece is connected to the steering shaft. When the steering shaft drives the switch pressing piece to rotate, the switch pressing piece contacts the travel switch.
[0018] As a preferred solution of the utility model, one end of the switch pressing piece is rotatably connected to the edge of the steering shaft, a slide groove is provided on the switch pressing piece, a guide column is fixed on the top shell, and the guide column is sleeved in the slide groove.
[0019] As a preferred solution of the utility model, a positioning rib is arranged in the top shell, an arc-shaped limiting groove is arranged on the steering shaft, and the positioning rib is sleeved in the arc-shaped limiting groove.
[0020] As a preferred solution of the utility model, the valve body comprises a left valve body and a right valve body which are connected to each other, and valve pads are arranged in the left valve body and the right valve body, and the valve pads are in contact with the ball.
[0021] As a preferred solution of the utility model, the inclined surfaces on both sides of the slot form an angle with the radial line of the steering shaft, and the cross-sectional shape of the end of the latch extending into the slot is an arc shape.
[0022] As a preferred solution of the utility model, a knob is connected to the steering shaft.
[0023] The beneficial effects of the utility model are:
[0024] 1. The torsion spring of the utility model is connected between the steering shaft and the valve body. In the valve-opening state, the torsion spring has been twisted by a certain angle compared to the initial position, and the torsion spring is twisted to have a restoring force. In the valve-opening state, the electromagnetic core assembly drives the latch to engage in the slot, offsetting the restoring force of the torsion spring, so that the shut-off valve remains in the valve-opening state. In an emergency, the equipment receives a valve-closing signal, and the driving force of the electromagnetic core assembly on the latch disappears. Under the restoring force of the torsion spring, the steering shaft rotates, and the latch is squeezed out of the slot, and the steering shaft continues to rotate to the valve-closing state. The shut-off valve of the utility model can automatically close the valve in an emergency to achieve automatic control.
[0025] 2. The utility model uses a mechanical structure to drive the mechanical structure to pre-tighten the torsion spring through electromagnetic force when the valve is opened. After receiving the valve closing command, the electromagnetic force disappears and drives the mechanical structure to release the torsion spring to drive the ball valve to rotate and close the valve. The valve closing time can be within 1 second.
[0026] 3. When the ball valve turns to close, the switch pressure piece touches the travel switch on the circuit board, providing an accurate valve closing signal, which is then transmitted to the control platform, so that it can accurately know whether the shut-off valve is in the open or closed state. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is an exploded view of the utility model;
[0028] Figure 2 It is a top view of the utility model in a valve-closed state;
[0029] Figure 3 yes Figure 2 Sectional view at AA in the middle;
[0030] Figure 4 This is the front view of the utility model in the valve-closed state;
[0031] Figure 5 yes Figure 4 Sectional view at the middle BB;
[0032] Figure 6 It is a top view of the utility model in the valve-opening state;
[0033] Figure 7 yes Figure 6 Sectional view at CC;
[0034] Figure 8 This is the front view of the utility model in the valve-closed state;
[0035] Fig. 9 yes Figure 8 Sectional view at DD in the middle;
[0036] Fig.10 This is the force analysis diagram when the pin is in the slot;
[0037] Fig.11 It is a partial structural diagram of the utility model in the valve-opening state;
[0038] Fig.12 It is a partial structural diagram of the utility model in the valve closing state.
[0039] In the figure: 1-top shell; 2-valve body; 3-steering shaft; 4-ball; 5-torsion spring; 6-electromagnetic iron core assembly; 7-housing; 8-circuit board; 9-switch pressing piece; 11-guide column; 12-positioning rib; 21-left valve body; 22-right valve body; 23-valve pad; 31-valve stem; 32-slot; 33-arc limit groove; 34-knob; 41-through hole; 61-latch pin; 62-electromagnetic iron core housing; 63-moving iron core; 64-fixed iron core; 65-button; 66-cover; 81-travel switch; 91-slide groove. DETAILED DESCRIPTION
[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.
[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.
[0042] like Figures 1 to 9As shown, the electromagnetic emergency shut-off valve of this embodiment includes a top shell 1, the lower part of the top shell 1 is connected to a valve body 2, a steering shaft 3 is installed in the top shell 1, the lower end of the rotating shaft is connected to a valve stem 31, the lower end of the valve stem 31 is connected to a ball 4, the ball 4 is arranged in the valve body 2, and a through hole 41 is arranged on the ball 4; a torsion spring 5 is connected between the steering shaft 3 and the valve body 2, and a slot 32 is arranged on the steering shaft 3; and an electromagnetic core assembly 6 is also included, and a latch 61 is connected in the electromagnetic core assembly 6, and one end of the latch 61 is inserted into the slot 32. The valve body 2 includes a left valve body 21 and a right valve body 22 connected to each other, and a valve pad 23 is arranged in the left valve body 21 and the right valve body 22, and the valve pad 23 contacts the ball 4. A knob 34 is connected to the steering shaft 3.
[0043] The torsion spring 5 of the utility model is connected between the steering shaft 3 and the valve body 2. In the valve opening state, the torsion spring 5 has been twisted by a certain angle compared to the initial position, and the torsion spring 5 is twisted to have a restoring force. In the valve opening state, the electromagnetic core assembly 6 drives the latch 61 to engage in the slot 32, offsetting the restoring force of the torsion spring 5, so that the cut-off valve remains in the valve opening state. In an emergency, the equipment receives a valve closing signal, and the driving force of the electromagnetic core assembly 6 on the latch 61 disappears. Under the restoring force of the torsion spring 5, the steering shaft 3 rotates, and the latch 61 is squeezed out of the slot 32, and the steering shaft 3 continues to rotate to the valve closing state.
[0044] It should be noted that the upper part of the steering shaft 3 and the knob 34 are connected by screws, and the flat square hole at the lower part of the steering shaft 3 is connected to the valve stem 31. The lower part of the valve stem 31 is plugged into the ball 4 with a slot through a flat square structure. There is a through hole 41 in the middle of the ball 4. When the axis of the through hole 41 is consistent with the direction of the electromagnetic valve connection pipeline, it is in an open valve state, and the conveying medium such as natural gas, artificial coal gas and other gases pass through. When the axis of the through hole 41 of the ball 4 is perpendicular to the direction of the electromagnetic valve connection pipeline, it is in a closed valve state, and the conveying medium cannot pass through. The lower part of the top shell 1 and the right valve body 22 are fixed by screws.
[0045] Specifically, the electromagnet core assembly 6 also includes an electromagnet core housing 62, a moving iron core 63 is sleeved in the electromagnet core housing 62, a latch 61 is fixed to the moving iron core 63, a permanent magnet and a fixed iron core 64 are also fixed in the electromagnet core housing 62, and an enameled coil is provided on the fixed iron core 64; when the enameled coil is not energized, the permanent magnet generates a magnetic force to attract the moving iron core 63 and the fixed iron core 64 together; when the enameled coil is energized, the fixed iron core 64 generates a magnetic force opposite to the permanent magnet, and the moving iron core 63 is no longer subjected to the magnetic attraction of the fixed iron core 64. The top shell 1 is connected to a shell 7, and the electromagnet core assembly 6 is arranged in the shell 7, and a circuit board 8 is also arranged in the shell 7, and the circuit board 8 is electrically connected to the enameled coil.
[0046] The electromagnetic core housing 62 is provided with a permanent magnet, an enameled coil, a silicon steel sheet, a plastic coil frame, and a fixed magnet; the enameled coil and the circuit board 8 are welded together. The permanent magnet generates magnetic force to attract the moving iron core 63 and the fixed iron core 64 together. The circuit board 8 is provided with a battery, an antenna, a travel switch 81, and a control circuit. When the circuit board 8 receives a valve closing signal from a gas detector or other control device, a pulse power supply is provided to the electromagnetic core assembly 6, and the enameled coil is energized to make the fixed iron core 64 generate a magnetic force opposite to the permanent magnet, so that the electromagnetic core assembly 6 has no magnetism.
[0047] There is a stepped hole in the middle of the electromagnetic core housing 62, and the moving iron core 63 can move axially in the large hole. The latch 61 passes through the small hole in the middle of the electromagnetic core housing 62 and is connected to the moving iron core 63. The other end of the moving iron core 63 is connected to the button 65. The latch 61 is a stepped shaft to form a limit step. The small outer diameter part of the latch 61 can pass through the electromagnetic core housing 62, and the large outer diameter part cannot pass through the electromagnetic core housing 62, that is, the electromagnetic core housing 62 blocks the limit step. When the valve is opened, the front end of the latch 61 extends into the slot 32 on the large outer circle of the steering shaft 3; when the valve is closed, the front end of the latch 61 stops on the large outer circle of the steering shaft 3. The electromagnetic core assembly 6 and the circuit board 8 are installed in the shell 7 and covered with a cover 66. There are holes in the front and back of the shell 7 that pass through the latch 61 and the moving iron core 63 respectively. The shell 7 is connected and fixed to the top shell 1 and the right valve body 22 by screws.
[0048] like Figure 2 to Figure 5 The valve is shown in the closed state, the through hole 41 of the ball 4 is perpendicular to the axis of the electromagnetic valve installation pipe, and the medium cannot pass through the electromagnetic valve. The permanent magnet of the electromagnetic core assembly 6 will attract the moving iron core 63 to move closer to the fixed iron core 64. Because the moving iron core 63 and the latch 61 are connected together, the magnetic force will pass through the moving iron core 63 to make the latch 61 press against the outer cylindrical surface of the steering shaft 3. When the moving iron core 63 and the fixed iron core 64 are close together, the magnetic force is the largest, and the magnetic force will decay to zero as the distance is pulled away. In our actual application, the magnetic force is greater than 4Kgf when they are close together, and there is still 0.3Kgf when the distance is 4mm. The mass of the three parts of the button 65, the moving iron core 63, and the latch 61 is about 30g in total. The magnetic force is greater than the mass of the three parts, and the three parts can be permanently attracted to the direction of the fixed iron core 64.
[0049] In the valve opening state, the torsion spring 5 has been twisted by a certain angle compared to the initial position, and is actually twisted 60° in the counterclockwise direction. Figure 6 to Figure 9 As shown, since the upper end of the torsion spring 5 is connected to the steering shaft 3, the steering shaft 3 will rotate clockwise due to the rebound force of the torsion spring 5, and the rib on the top shell 1 clamps the steering shaft 3 to stay in the closed position.
[0050] In order to make the cut-off valve rotate to the right position when closing or opening the valve, a positioning rib 12 is provided in the top shell 1, and an arc-shaped limiting groove 33 is provided on the steering shaft 3. The positioning rib 12 is sleeved in the arc-shaped limiting groove 33. The inclined surfaces on both sides of the clamping groove 32 have an angle with the radial line of the steering shaft 3, and the cross-section of the end of the latch 61 extending into the clamping groove 32 is an arc shape.
[0051] When the knob 34 is rotated about 90° in the counterclockwise direction, the knob 34 drives the steering shaft 3 to rotate. Since the positioning rib 12 on the top shell 1 limits the steering shaft 3 to stay at the 90° rotation position, the latch 61 and the movable iron core 63 are moved toward the steering shaft 3 by the magnetic force. The latch 61 extends into the slot 32 of the steering shaft 3. The movable iron core 63 and the fixed iron core 64 are pressed together by the magnetic force to prevent the steering shaft 3 from squeezing the latch 61 out of the slot.
[0052] The knob 34 drives the torsion spring 5 to rotate 90° through the steering shaft 3. When the force that causes the knob 34 to rotate disappears, the torsion force of the torsion spring 5 is offset by the pressure between the steering shaft 3 and the latch 61. Fig.10 As shown, the pressure is decomposed into two directional forces on the inclined plane, the horizontal force F 平 and the vertical force F 垂 When the magnetic force on the moving iron core 63 is greater than F 平 When the electromagnetic valve receives the valve closing command, the circuit board 8 supplies pulse power to the electromagnetic core assembly 6, and the coil generates a magnetic force in the opposite direction to the permanent magnet to offset the magnetic force of the permanent magnet. The moving iron core 63 is not attracted by the magnetic force, and the pin 61 only receives the F 平 The steering shaft 3 is forced to exit the slot 32 of the steering shaft 3 by force, and the steering shaft 3 is reset by the torsion spring 5 and drives the ball 4 to rotate through the valve stem 31, so that the solenoid valve is switched from the open valve state to the closed valve state.
[0053] Furthermore, a travel switch 81 is provided on the circuit board 8 , and a switch pressing piece 9 is connected to the steering shaft 3 . When the steering shaft 3 drives the switch pressing piece 9 to rotate, the switch pressing piece 9 contacts the travel switch 81 .
[0054] Specifically, one end of the switch pressing piece 9 is rotatably connected to the edge of the steering shaft 3 , a slide groove 91 is provided on the switch pressing piece 9 , a guide column 11 is fixed on the top shell 1 , and the guide column 11 is sleeved in the slide groove 91 .
[0055] like Fig.11 and Fig.12 As shown, the switch pressing piece 9 connected to the steering shaft 3 by rivets does not touch the travel switch 81 on the circuit board 8 when the valve is opened. When the valve is closed, the rotation of the steering shaft 3 will drive the switch pressing piece 9 to rotate and touch the travel switch 81. The action of the travel switch 81 allows the circuit board 8 to receive the valve closing signal and transmit it to the control device.
[0056] The cut-off valve of the utility model can automatically close the valve in an emergency situation to realize automatic control.
[0057] The utility model uses a mechanical structure to pre-tighten the torsion spring 5 by electromagnetic force when opening the valve. After receiving the valve closing instruction, the electromagnetic force disappears and drives the mechanical structure to release the torsion spring 5 to drive the ball valve to rotate and close the valve. The valve closing time can be within 1 second.
[0058] The valve closing gas circuit of the utility model adopts a ball valve structure, and the gas passage is an "I"-shaped gas circuit, which is convenient for air flow to pass through and has a large flow rate. In actual application tests, the flow rate of the ball valve is 50% larger than that of the stop valve.
[0059] When the ball valve rotates to close, the switch pressing piece 9 touches the travel switch 81 on the circuit board 8, providing an accurate valve closing signal, which is then transmitted to the control platform, so that it can accurately know whether the cut-off valve is in the open or closed state.
[0060] In the valve open state, the enameled coil is not energized, and the permanent magnet generates magnetic force to attract the moving iron core 63 and the fixed iron core 64 together; when the enameled coil is energized, the fixed iron core 64 generates magnetic force in the opposite direction to the permanent magnet, and the moving iron core 63 is no longer subject to the magnetic attraction of the fixed iron core 64. Therefore, in the normally open state, the cut-off valve of the utility model does not consume electricity, can save energy and ensure reliability.
[0061] The present utility model is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present utility model. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present utility model fall within the protection scope of the present utility model.
Claims
1. An electromagnetic emergency shut-off valve, characterized in that: The invention comprises a top shell (1), the lower part of which is connected to a valve body (2), a steering shaft (3) is installed in the top shell (1), the lower end of the rotating shaft is connected to a valve stem (31), the lower end of the valve stem (31) is connected to a ball (4), the ball (4) is arranged in the valve body (2), and a through hole (41) is arranged on the ball (4); a torsion spring (5) is connected between the steering shaft (3) and the valve body (2), and a slot (32) is arranged on the steering shaft (3); and an electromagnetic core assembly (6) is also included, a latch (61) is connected in the electromagnetic core assembly (6), and one end of the latch (61) is inserted into the slot (32).
2. The electromagnetic emergency shut-off valve according to claim 1, characterized in that: The electromagnetic core assembly (6) further comprises an electromagnetic core housing (62), a moving iron core (63) being sleeved in the electromagnetic core housing (62), a latch (61) being fixed to the moving iron core (63), a permanent magnet and a fixed iron core (64) being fixed in the electromagnetic core housing (62), and an enameled coil being sleeved on the fixed iron core (64); when the enameled coil is not energized, the permanent magnet generates a magnetic force to attract the moving iron core (63) and the fixed iron core (64) together; when the enameled coil is energized, the fixed iron core (64) generates a magnetic force in the opposite direction to that of the permanent magnet, and the moving iron core (63) is no longer subjected to the magnetic attraction force of the fixed iron core (64).
3. The electromagnetic emergency shut-off valve according to claim 2, characterized in that: The latch (61) is provided with a limiting step, the latch (61) is sleeved on the electromagnetic core housing (62), and the electromagnetic core housing (62) blocks the limiting step.
4. The electromagnetic emergency shut-off valve according to claim 2, characterized in that: The top shell (1) is connected to an outer shell (7), the electromagnetic core assembly (6) is arranged in the outer shell (7), a circuit board (8) is also arranged in the outer shell (7), and the circuit board (8) is electrically connected to the enameled coil.
5. The electromagnetic emergency shut-off valve according to claim 4, characterized in that: The circuit board (8) is provided with a travel switch (81), and the steering shaft (3) is connected with a switch pressing piece (9). When the steering shaft (3) drives the switch pressing piece (9) to rotate, the switch pressing piece (9) contacts the travel switch (81).
6. The electromagnetic emergency shut-off valve according to claim 5, characterized in that: One end of the switch pressing piece (9) is rotatably connected to the edge of the steering shaft (3); a slide groove (91) is provided on the switch pressing piece (9); a guide column (11) is fixed on the top shell (1); and the guide column (11) is sleeved in the slide groove (91).
7. The electromagnetic emergency shut-off valve according to claim 1, characterized in that: A positioning rib (12) is arranged inside the top shell (1), an arc-shaped limiting groove (33) is arranged on the steering shaft (3), and the positioning rib (12) is sleeved in the arc-shaped limiting groove (33).
8. The electromagnetic emergency shut-off valve according to claim 1, characterized in that: The valve body (2) comprises a left valve body (21) and a right valve body (22) which are connected to each other. A valve pad (23) is arranged in each of the left valve body (21) and the right valve body (22), and the valve pad (23) is in contact with the ball (4).
9. The electromagnetic emergency shut-off valve according to claim 1, characterized in that: The inclined surfaces on both sides of the slot (32) form an angle with the radial line of the steering shaft (3), and the cross-section of one end of the latch pin (61) extending into the slot (32) is in the shape of an arc.
10. An electromagnetic emergency shut-off valve according to any one of claims 1 to 9, characterized in that: The steering shaft (3) is connected with a knob (34).