A device for photoacoustic imaging of animal heads

Abstract

The present invention discloses a device for photoacoustic imaging of an animal's head, and belongs to the technical field of ultrasonic imaging. The device includes an ultrasonic transducer, a coupling agent assembly, and a coupling agent control assembly. The middle part of the ultrasonic transducer is provided with a through hole, and the inner peripheral wall of the through hole is provided with an ultrasonic array ring. The coupling agent assembly includes a transparent cover plate, an elastic membrane, and a connector. The transparent cover plate is laid on the top end surface of the ultrasonic transducer to seal the top of the through hole. The outer edge of the elastic membrane is connected to the bottom end surface of the ultrasonic transducer through a connector to seal the bottom of the through hole. A coupling agent cavity is formed between the transparent cover plate, the elastic membrane, and the ultrasonic transducer, and the coupling agent cavity is filled with coupling agent. The coupling agent control assembly includes a first stop valve, a second stop valve, a first hydraulic pump, and a second hydraulic pump. The device provided by the present disclosure can reduce the stress of the coupling agent on the head of the animal.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultrasonic imaging, and more specifically, relates to a device for photoacoustic imaging of an animal's head. Background Art

[0002] Animals are widely used in the field of clinical medicine and have great scientific research value in cancer lesion models, cancer treatment, drug evaluation, hemodynamic research, etc. Common animals include mice, rats and rabbits. In order to avoid causing damage to or killing animals, animals are usually imaged with photoacoustics through an ultrasonic transducer array. Specifically, acoustic signals are generated under pulsed light irradiation (received by the ultrasonic array ring), so that the animals can be analyzed and diagnosed based on the acoustic signals.

[0003] Acoustic signals need to be mediated by a coupling agent to reduce ultrasonic reflection, increase ultrasonic transmission, and facilitate imaging. For photoacoustic imaging of an animal's head, if the animal's head is immersed in the coupling agent, the animal will drown. In related technologies, in order to prevent the animal from being immersed, the coupling agent and the animal can be isolated by an elastic film, and then the head of the animal to be tested can be pushed into the film. Specifically, after the animal is anesthetized and restrained, ultrasound gel is applied to the animal's head and protruded toward the array imaging plane.

[0004] However, although the above method can solve the problem of immersion of the animal's head, during the photoacoustic imaging process, the animal's head needs to be pushed into the ultrasound array ring, causing the elastic film to concave, and the coupling agent produces a large stress on the animal's head. These stresses have a great impact on the animal, will interfere with the experiment, and may even kill the animal. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a device for photoacoustic imaging of animal heads, which aims to reduce the stress of the coupling agent on the animal's head, thereby solving the technical problem that the coupling agent exerts excessive stress on the animal and affects the experiment.

[0006] To achieve the above-mentioned object, the present invention provides a device for photoacoustic imaging of an animal head, the device comprising an ultrasonic transducer, a coupling agent component and a coupling agent control component;

[0007] The ultrasonic transducer has a through hole in the middle, and an ultrasonic array ring is provided on the inner peripheral wall of the through hole;

[0008] The coupling agent assembly comprises a transparent cover plate, an elastic film and a connector, wherein the transparent cover plate is laid on the top end surface of the ultrasonic transducer to seal the top of the through hole, the outer edge of the elastic film and the bottom end surface of the ultrasonic transducer are connected together through a connector to seal the bottom of the through hole, and a coupling agent cavity is formed between the transparent cover plate, the elastic film and the ultrasonic transducer, and the coupling agent cavity is filled with a coupling agent;

[0009] The coupling agent control assembly includes a first stop valve, a second stop valve, a first hydraulic pump, and a second hydraulic pump. The inlet of the first stop valve and the outlet of the second stop valve are both communicated with the coupling agent chamber, the outlet of the first stop valve is communicated with the inlet of the first hydraulic pump, and the inlet of the second stop valve is communicated with the inlet of the second hydraulic pump.

[0010] Optionally, the connecting member includes a first clamping ring and a second clamping ring, the first clamping ring is located on the bottom end surface of the ultrasonic transducer, and the first clamping ring is coaxially arranged with the through hole, the second clamping ring and the first clamping ring are clamped together, and the outer edge of the elastic membrane is clamped between the first clamping ring and the second clamping ring.

[0011] Optionally, the connecting member is a fixing ring, the fixing ring is located on the bottom end surface of the ultrasonic transducer, the fixing ring is coaxially arranged with the through hole, and the outer edge of the elastic membrane is adhered to the fixing ring.

[0012] Optionally, the fixing ring is made of at least one of polyurethane, silicone and rubber.

[0013] Optionally, the coupling agent control assembly further includes a box for storing coupling agent, and the first hydraulic pump and the second hydraulic pump are both in communication with the box.

[0014] Optionally, the device further comprises a support member, which is arranged opposite to the ultrasonic transducer and is located below the ultrasonic transducer to support the animal.

[0015] Optionally, the support member includes a support rod and a base, the support rod is coaxially arranged with the through hole, and the bottom end of the support rod is inserted into the base.

[0016] Optionally, the support member further includes a support plate, the support plate is located on the top of the support rod, and a plate surface of the support plate facing the through hole is a curved surface adapted to the animal.

[0017] Optionally, the coupling agent control assembly further includes a first conduit, which is inserted into the transparent cover plate, wherein a first end of the first conduit is communicated with the coupling agent cavity, and a second end of the first conduit is communicated with an inlet of the first stop valve.

[0018] Optionally, the coupling agent control assembly further includes a second conduit, which is inserted into the connector, wherein a first end of the second conduit is communicated with the coupling agent cavity, and a second end of the second conduit is communicated with an outlet of the second stop valve.

[0019] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0020] For a device for photoacoustic imaging of an animal's head provided in an embodiment of the present invention, when performing photoacoustic imaging on the animal's head, the animal's head is placed at the lower part of a through hole, and pulsed light is excited at the upper part of the through hole. The pulsed light excites ultrasonic waves after acting on the animal's head, which are received by the ultrasonic array ring, and then the animal is analyzed and diagnosed based on the acoustic signal.

[0021] In addition, a transparent cover is laid on the top surface of the ultrasonic transducer to seal the top of the through hole, and the outer edge of the elastic membrane is connected to the bottom surface of the ultrasonic transducer through a connector to seal the bottom of the through hole. A coupling agent cavity is formed between the transparent cover, the elastic membrane and the ultrasonic transducer, and the coupling agent cavity is filled with a coupling agent. Then, on the basis of the coupling agent cavity being filled with a coupling agent, by applying ultrasonic gel on the animal's head and making the animal's head fit with the elastic membrane, not only can ultrasonic transmission be enhanced, but the animal can also be prevented from being immersed in the coupling agent through the elastic membrane.

[0022] Furthermore, the inlet of the first stop valve and the outlet of the second stop valve are both connected to the coupling agent chamber, the outlet of the first stop valve is connected to the inlet of the first hydraulic pump, and the inlet of the second stop valve is connected to the inlet of the second hydraulic pump. Therefore, when the first stop valve and the second stop valve are opened and the second hydraulic pump is started, the coupling agent can be injected into the coupling agent chamber through the second hydraulic pump to achieve the injection of the coupling agent, and during the injection of the coupling agent, the gas in the coupling agent chamber can be discharged through the first stop valve and the first hydraulic pump in turn to avoid air interference with ultrasonic transmission. After the coupling agent is injected, the second stop valve and the second hydraulic pump are closed, the first stop valve is kept open, and the first hydraulic pump is started. After a certain amount of coupling agent is pumped out, a negative pressure is formed in the coupling agent chamber, and under the action of atmospheric pressure, the elastic membrane is stretched inward and automatically becomes concave, so that most of the stress of the coupling agent can be dispersed to the elastic membrane (the stress on the animal's head is greatly reduced), thereby reducing the stress of the coupling agent on the animal's head, so that the animal's head can be easily placed in the ultrasonic array ring.

[0023] That is to say, when performing photoacoustic imaging on an animal's head, the device provided by the present disclosure can not only enhance ultrasound transmission and prevent the animal from being immersed in a coupling agent, but also reduce the stress of the coupling agent on the animal's head. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of a device for photoacoustic imaging of an animal head provided in this embodiment;

[0025] Figure 2 is a top view of the ultrasonic transducer provided in this embodiment;

[0026] Figure 3 is a schematic diagram of the use of the device provided in this embodiment;

[0027] Figure 4 is a schematic diagram of a first state of the elastic membrane provided by this embodiment;

[0028] Figure 5 is a schematic diagram of a second state of the elastic membrane provided by this embodiment;

[0029] Figure 6 is a schematic diagram of a third state of the elastic membrane provided in this embodiment;

[0030] Figure 7 is a schematic structural diagram of a connecting piece provided in this embodiment;

[0031] Figure 8 It is a schematic diagram of the structure of another connecting piece provided in this embodiment.

[0032] The symbols in the figure mean the following:

[0033] 1. Ultrasonic transducer; 11. Through hole; 12. Ultrasonic array ring; 2. Coupling agent assembly; 21. Transparent cover; 22. Elastic membrane; 23. Connector; 231. First clamp ring; 232. Second clamp ring; 233. Fixed ring; 24. Coupling agent cavity; 3. Coupling agent control assembly; 31. First stop valve; 32. Second stop valve; 33. First hydraulic pump; 34. Second hydraulic pump; 35. Box; 36. First conduit; 37. Second conduit; 4. Support member; 41. Support rod; 411. First shaft rod; 412. Second shaft rod; 42. Base; 43. Support plate; 100. Animal; 200. Pulsed light. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Figure 1 is a schematic diagram of the structure of a device for photoacoustic imaging of an animal head provided in this embodiment, such as Figure 1As shown, the device includes an ultrasonic transducer 1, a coupling agent component 2 and a coupling agent control component 3.

[0036] The ultrasonic transducer 1 has a through hole 11 in the middle, and an ultrasonic array ring 12 is provided on the inner peripheral wall of the through hole 11 (see Figure 2 ).

[0037] The coupling agent assembly 2 includes a transparent cover plate 21, an elastic membrane 22 and a connector 23. The transparent cover plate 21 is laid on the top surface of the ultrasonic transducer 1 to seal the top of the through hole 11. The outer edge of the elastic membrane 22 and the bottom surface of the ultrasonic transducer 1 are connected together through the connector 23 to seal the bottom of the through hole 11. A coupling agent cavity 24 is formed between the transparent cover plate 21, the elastic membrane 22 and the ultrasonic transducer 1, and the coupling agent cavity 24 is filled with coupling agent.

[0038] The coupling agent control assembly 3 includes a first stop valve 31, a second stop valve 32, a first hydraulic pump 33 and a second hydraulic pump 34. The inlet of the first stop valve 31 and the outlet of the second stop valve 32 are both connected to the coupling agent chamber 24, the outlet of the first stop valve 31 is connected to the inlet of the first hydraulic pump 33, and the inlet of the second stop valve 32 is connected to the inlet of the second hydraulic pump 34.

[0039] For a device for photoacoustic imaging of an animal's head provided in an embodiment of the present invention, when performing photoacoustic imaging on the head of an animal 100, the head of the animal 100 is placed at the lower part of a through hole 11, and pulsed light 200 is emitted at the upper part of the through hole 11. The pulsed light 200 excites ultrasonic waves after acting on the head of the animal 100, which are received by the ultrasonic array ring 12, and then the animal 100 is analyzed and diagnosed based on the acoustic signal.

[0040] In addition, the transparent cover plate 21 is laid on the top surface of the ultrasonic transducer 1 to seal the top of the through hole 11, the outer edge of the elastic membrane 22 is connected to the bottom surface of the ultrasonic transducer 1 through the connector 23 to seal the bottom of the through hole 11, and a coupling agent cavity 24 is formed between the transparent cover plate 21, the elastic membrane 22 and the ultrasonic transducer 1, and the coupling agent cavity 24 is filled with a coupling agent. Then, on the basis of the coupling agent cavity 24 being filled with a coupling agent, by applying ultrasonic gel on the head of the animal 100, and making the head of the animal 100 fit the elastic membrane 22 (see Figure 3 ), thereby not only enhancing ultrasound transmission but also preventing the animal 100 from being immersed in the coupling agent through the elastic membrane 22.

[0041] Furthermore, the inlet of the first stop valve 31 and the outlet of the second stop valve 32 are both connected to the coupling agent chamber 24, the outlet of the first stop valve 31 is connected to the inlet of the first hydraulic pump 33, and the inlet of the second stop valve 32 is connected to the inlet of the second hydraulic pump 34. Therefore, when the first stop valve 31 and the second stop valve 32 are opened and the second hydraulic pump 34 is started, the coupling agent can be injected into the coupling agent chamber 24 through the second hydraulic pump 34, thereby achieving the injection of the coupling agent (see Figure 4 ), and during the coupling agent injection process, the gas in the coupling agent chamber 24 can be discharged through the first stop valve 31 and the first hydraulic pump 33 in turn to avoid air interference with ultrasonic transmission. After the coupling agent is injected, the second stop valve 32 and the second hydraulic pump 34 are closed, the first stop valve 31 is kept open, and the first hydraulic pump 33 is started. After a certain amount of coupling agent is pumped out, a negative pressure is formed in the coupling agent chamber 24, and under the action of atmospheric pressure, the elastic membrane 22 is stretched inward and automatically becomes concave (see Figure 5 ), most of the stress of the coupling agent can be dispersed to the elastic membrane 22 (the stress on the head of the animal 100 is greatly reduced), thereby reducing the stress of the coupling agent on the head of the animal 100, and the head of the animal 100 can be easily placed in the ultrasound array ring 12.

[0042] That is to say, when performing ultrasonic imaging on the head of the animal 100, the device provided by the present invention can not only enhance ultrasound transmission and prevent the animal 100 from being immersed in the coupling agent, but also reduce the stress of the coupling agent on the elastic membrane 22, thereby reducing the stress of the coupling agent on the head of the animal 100.

[0043] It should be noted that in other embodiments of the present disclosure, the first hydraulic pump 33 and the second hydraulic pump 34 may be integrated together to form a bidirectional pump, through which not only the coupling agent can be injected but also the coupling agent can be pumped out.

[0044] It should be noted that, in this embodiment, the depression depth of the elastic membrane 22 can be appropriately adjusted by controlling the volume of the coupling agent in the coupling agent cavity 24 according to the size of the animal 100 or the different positions of the head of the animal 100 (see Figure 6 ) to better achieve the fit between the head of the animal 100 and the elastic membrane 22.

[0045] Exemplarily, the transparent cover plate 21 may be a glass plate to ensure that the pulsed light 200 can be smoothly transmitted into the head of the animal 100 .

[0046] Figure 7 is a schematic diagram of the structure of a connecting member provided in this embodiment, such as Figure 7As shown, the connecting member 23 includes a first clamping ring 231 and a second clamping ring 232. The first clamping ring 231 is located on the bottom end surface of the ultrasonic transducer 1, and the first clamping ring 231 is coaxially arranged with the through hole 11. The second clamping ring 232 and the first clamping ring 231 are clamped together, and the outer edge of the elastic membrane 22 is clamped between the first clamping ring 231 and the second clamping ring 232.

[0047] In the above embodiment, the elastic membrane 22 can be stably clamped by the clamping of the first clamping ring 231 and the second clamping ring 232, thereby increasing the fixing strength of the elastic membrane 22 and facilitating pressure bearing.

[0048] Figure 8 is a schematic diagram of the structure of another connecting member provided in this embodiment, such as Figure 8 As shown, the connecting member 23 is a fixing ring 233 , which is located on the bottom end surface of the ultrasonic transducer 1 , and the fixing ring 233 is coaxially arranged with the through hole 11 , and the outer edge of the elastic membrane 22 is adhered to the fixing ring 233 .

[0049] In the above embodiment, by adhering the elastic membrane 22 and the fixing ring 233 together, the installation efficiency of the elastic membrane 22 can be improved.

[0050] Exemplarily, the material of the fixing ring 233 is at least one of polyurethane, silicone and rubber.

[0051] In the above embodiment, polyurethane, silicone or rubber are all membrane-affinity materials, and the fixing ring 233 is polyurethane, silicone or rubber, which can enable the elastic membrane 22 to be firmly adhered.

[0052] See again Figure 1 The coupling agent control assembly 3 further includes a box 35 for storing the coupling agent, and the first hydraulic pump 33 and the second hydraulic pump 34 are both connected to the box 35 .

[0053] In the above embodiment, the box 35 is convenient for recovering the coupling agent, so that the coupling agent can be recycled.

[0054] In this embodiment, the coupling agent control assembly 3 further includes a first conduit 36 ​​, which is inserted into the transparent cover plate 21 , a first end of the first conduit 36 ​​is connected to the coupling agent chamber 24 , and a second end of the first conduit 36 ​​is connected to the inlet of the first stop valve 31 .

[0055] In the above embodiment, the first conduit 36 ​​serves to connect the coupling agent chamber 24 and the first stop valve 31 to facilitate the circulation of the coupling agent.

[0056] Similarly, the coupling agent control assembly 3 also includes a second conduit 37 , which is inserted into the connector 23 , a first end of the second conduit 37 is connected to the coupling agent chamber 24 , and a second end of the second conduit 37 is connected to the outlet of the second stop valve 32 .

[0057] In the above embodiment, the second conduit 37 serves to connect the coupling agent chamber 24 and the second stop valve 32, and also facilitates the circulation of the coupling agent.

[0058] Exemplarily, the coupling agent in the coupling agent cavity 24 may be water or ultrasound gel.

[0059] See again Figure 3 The device also includes a support member 4, which is arranged opposite to the ultrasonic transducer 1 and is located at the lower part of the ultrasonic transducer 1 to support the animal 100.

[0060] In the above embodiment, the support member 4 plays a role in stably supporting the animal 100 , thereby preventing the animal 100 from moving during photoacoustic imaging.

[0061] Optionally, the support member 4 includes a support rod 41 and a base 42 , the support rod 41 is coaxially arranged with the through hole 11 , and the bottom end of the support rod 41 is inserted into the base 42 .

[0062] In the above embodiment, the base 42 supports the support rod 41 , so that the support rod 41 is not easy to move or tilt, and the support rod 41 supports the animal 100 .

[0063] Exemplarily, the support rod 41 includes a first shaft rod 411 and a second shaft rod 412, the first shaft rod 411 and the second shaft rod 412 are coaxially arranged, and the diameter of the first shaft rod 411 is larger than the diameter of the second shaft rod 412, and the bottom end of the first shaft rod 411 is inserted into the base 42, and the top end of the first shaft rod 411 is mounted on the bottom end of the second shaft rod 412, thereby increasing the support area on the base 42.

[0064] In this embodiment, the support member 4 further includes a support plate 43 , which is located on the top of the support rod 41 , and a plate surface of the support plate 43 facing the through hole 11 is a curved surface that matches the animal 100 .

[0065] In the above embodiment, the surface of the support plate 43 is adapted to the animal 100 , which can not only increase the support area, but also increase the comfort of the animal 100 and avoid the death of the animal 100 .

[0066] Exemplarily, the support plate 43 may also have a heating function, which can make the temperature of the support plate 43 consistent with the body temperature of the animal 100 , which is helpful for maintaining the body temperature of the animal 100 .

[0067] The present invention provides a device for photoacoustic imaging of an animal head having the following advantages:

[0068] (1) Avoid immersing the animal's head in water, which may cause suffocation and death.

[0069] (2) It can relieve the pressure on the animal's head and improve its survival rate.

[0070] (3) A support plate 43 capable of being heated is provided to maintain the body temperature of the animal 100.

[0071] (4) The transparent cover plate 21 does not block the excitation light, and the through hole 11 does not block the acoustic signal, which facilitates the collection of photoacoustic signals.

[0072] (5) By controlling the volume of the coupling agent in the coupling agent cavity 24, the depression depth of the elastic membrane 22 can be controlled, so that different parts of the head of the animal 100 can be located on the ultrasound array imaging plane.

[0073] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for photoacoustic imaging of an animal's head, characterized in that: The device comprises an ultrasonic transducer (1), a coupling agent component (2) and a coupling agent control component (3); The ultrasonic transducer (1) has a through hole (11) in the middle, and an ultrasonic array ring (12) is provided on the inner peripheral wall of the through hole (11); The coupling agent assembly (2) comprises a transparent cover plate (21), an elastic membrane (22) and a connecting piece (23); the transparent cover plate (21) is laid on the top end surface of the ultrasonic transducer (1) to seal the top of the through hole (11); the outer edge of the elastic membrane (22) and the bottom end surface of the ultrasonic transducer (1) are connected together through the connecting piece (23) to seal the bottom of the through hole (11); a coupling agent cavity (24) is formed between the transparent cover plate (21), the elastic membrane (22) and the ultrasonic transducer (1); and the coupling agent cavity (24) is filled with a coupling agent; The coupling agent control assembly (3) comprises a first stop valve (31), a second stop valve (32), a first hydraulic pump (33) and a second hydraulic pump (34); the inlet of the first stop valve (31) and the outlet of the second stop valve (32) are both in communication with the coupling agent chamber (24); the outlet of the first stop valve (31) is in communication with the inlet of the first hydraulic pump (33); and the inlet of the second stop valve (32) is in communication with the inlet of the second hydraulic pump (34); The device further comprises a pulse light (200), wherein the pulse light (200) is located above the transparent cover plate (21) and irradiates towards the through hole (11).

2. The device for photoacoustic imaging of an animal head according to claim 1, characterized in that: The connecting member (23) comprises a first clamping ring (231) and a second clamping ring (232), wherein the first clamping ring (231) is located on the bottom end surface of the ultrasonic transducer (1), and the first clamping ring (231) is coaxially arranged with the through hole (11), the second clamping ring (232) and the first clamping ring (231) are clamped together, and the outer edge of the elastic membrane (22) is clamped between the first clamping ring (231) and the second clamping ring (232).

3. The device for photoacoustic imaging of an animal head according to claim 1, characterized in that: The connecting member (23) is a fixing ring (233), the fixing ring (233) is located on the bottom end surface of the ultrasonic transducer (1), the fixing ring (233) is coaxially arranged with the through hole (11), and the outer edge of the elastic membrane (22) is adhered to the fixing ring (233).

4. The device for photoacoustic imaging of an animal head according to claim 3, characterized in that: The material of the fixing ring (233) is at least one of polyurethane, silicone and rubber.

5. The device for photoacoustic imaging of an animal head according to claim 1, characterized in that: The coupling agent control assembly (3) further comprises a box (35) for storing coupling agent, and the first hydraulic pump (33) and the second hydraulic pump (34) are both in communication with the box (35).

6. The device for photoacoustic imaging of an animal head according to claim 1, characterized in that: The device further comprises a support member (4), wherein the support member (4) is arranged opposite to the ultrasonic transducer (1), and the support member (4) is located below the ultrasonic transducer (1) to support the animal (100).

7. The device for photoacoustic imaging of an animal head according to claim 6, characterized in that: The support member (4) comprises a support rod (41) and a base (42); the support rod (41) is coaxially arranged with the through hole (11); and the bottom end of the support rod (41) is inserted into the base (42).

8. The device for photoacoustic imaging of an animal head according to claim 7, characterized in that: The support member (4) further comprises a support plate (43), wherein the support plate (43) is located at the top of the support rod (41), and the plate surface of the support plate (43) facing the through hole (11) is a curved surface adapted to the animal (100).

9. A device for photoacoustic imaging of an animal head according to any one of claims 1 to 8, characterized in that: The coupling agent control assembly (3) further comprises a first conduit (36), wherein the first conduit (36) is inserted into the transparent cover plate (21), a first end of the first conduit (36) is communicated with the coupling agent chamber (24), and a second end of the first conduit (36) is communicated with an inlet of the first stop valve (31).

10. A device for photoacoustic imaging of an animal head according to any one of claims 1 to 8, characterized in that: The coupling agent control assembly (3) further comprises a second conduit (37), wherein the second conduit (37) is inserted into the connecting piece (23), a first end of the second conduit (37) is communicated with the coupling agent chamber (24), and a second end of the second conduit (37) is communicated with an outlet of the second stop valve (32).

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