Safety protection diaphragm for valve failure early warning

Abstract

The invention belongs to the technical field of nuclear power, and particularly relates to a safety protection diaphragm used for valve failure early warning, the safety protection diaphragm used for valve failure early warning comprises a supporting diaphragm and a protection diaphragm overlapped with the supporting diaphragm, an electrode layer is arranged in the protection diaphragm, the protection diaphragm is externally connected with monitoring equipment, and the electrode layer is arranged in the protection diaphragm. And monitoring the change of the resistance value of the electrode layer through monitoring equipment and judging whether the diaphragm is invalid or not. According to the safety protection diaphragm, the supporting diaphragm and the protection diaphragm are stacked together, the supporting diaphragm bears main air pressure loads during normal work, after the supporting diaphragm loses efficacy, the protection diaphragm is subjected to the air pressure effect, whether the diaphragm loses efficacy or not is judged by monitoring the change of the resistance value of the electrode layer through monitoring equipment, and the safety protection diaphragm is obtained. Therefore, a worker is reminded to replace the diaphragm in time, time is won for the worker to make an emergency in advance, adverse effects caused by valve faults are reduced, and time and energy of valve maintenance are saved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power, and in particular relates to a safety protection diaphragm for valve failure early warning. Background Art

[0002] The diaphragms of the regulating valves currently used in nuclear power plants frequently malfunction. Once the diaphragm ruptures and causes gas leakage, the valve actuator will fail. Since the regulating valves currently used do not have the ability to predict diaphragm failure, there is no way to give on-site personnel enough time to carry out emergency response, which will lead to untimely response by on-site personnel, resulting in shutdown or reactor shutdown accidents, and may even cause nuclear leakage. Summary of the invention

[0003] The main purpose of the present invention is to propose a safety protection diaphragm for valve failure warning. The safety protection diaphragm of the present invention overlaps a supporting diaphragm and a protective diaphragm. During normal operation, the supporting diaphragm bears the main air pressure load, and the protective diaphragm moves with the supporting diaphragm and does not bear the air pressure load at this time. When the supporting diaphragm fails, the protective diaphragm is affected by the air pressure. The resistance value change of the electrode layer is monitored by the monitoring equipment to determine whether the diaphragm has failed, and the staff is reminded to replace the diaphragm in time, which buys time for the staff to prepare for emergencies in advance, reduces the adverse effects caused by valve failures, and saves time and energy for valve maintenance.

[0004] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0005] The present invention provides a safety protection diaphragm for valve failure warning, the safety protection diaphragm includes a supporting diaphragm and a protective diaphragm overlapped with the supporting diaphragm, an electrode layer is arranged inside the protective diaphragm, and the protective diaphragm is externally connected to a monitoring device to monitor the resistance value change of the electrode layer through the monitoring device and determine whether the diaphragm has failed.

[0006] In some embodiments of the present invention, the stiffness of the supporting membrane is greater than the stiffness of the protective membrane.

[0007] In some embodiments of the present invention, the protective diaphragm includes a diaphragm body and a support layer disposed inside the diaphragm body, the support layer and the electrode layer are stacked with intervals along the thickness direction of the diaphragm body, and the electrode layer is externally connected to a monitoring device.

[0008] In some embodiments of the present invention, the stiffness of the electrode layer is less than the stiffness of the support layer.

[0009] In some embodiments of the present invention, the electrode layer is formed by weaving conductive yarn and non-conductive yarn, and the conductive yarn is used to connect electrode leads to external monitoring equipment; and / or, the supporting layer is formed by weaving non-conductive yarn.

[0010] In some embodiments of the present invention, the conductive yarn comprises silver-plated nylon conductive yarn; and / or, the non-conductive yarn comprises polyester yarn.

[0011] In some embodiments of the present invention, the diaphragm body includes a first diaphragm body layer, a second diaphragm body layer and a third diaphragm body layer stacked in sequence along its thickness direction, the electrode layer is located between the first diaphragm body layer and the second diaphragm body layer, and the support layer is located between the second diaphragm body layer and the third diaphragm body layer.

[0012] In some embodiments of the present invention, the material of the supporting membrane includes rubber.

[0013] In some embodiments of the present invention, the material of the diaphragm body includes rubber.

[0014] In some embodiments of the present invention, the monitoring device includes a resistance sensor connected to the electrode layer.

[0015] In some embodiments of the present invention, the monitoring device includes an air pressure sensor for monitoring changes in the air pressure value of the safety protection diaphragm and determining whether the diaphragm has failed.

[0016] Compared with the prior art, the present invention achieves the following technical effects:

[0017] The safety protection diaphragm in the present invention overlaps the supporting diaphragm and the protective diaphragm together. During normal operation, the supporting diaphragm bears the main air pressure load, and the protective diaphragm moves with the supporting diaphragm and does not bear the air pressure load at this time. When the supporting diaphragm fails, the protective diaphragm is affected by the air pressure. The resistance value change of the electrode layer is monitored by the monitoring equipment to determine whether the diaphragm has failed, and the staff is reminded to replace the diaphragm in time, which buys time for the staff to prepare for emergencies in advance, reduces the adverse effects caused by valve failures, and saves time and energy for valve maintenance.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0020] Figure 1 A schematic cross-sectional view of a safety protection diaphragm for valve failure warning according to some embodiments of the present invention;

[0021] Figure 2 Schematic cross-sectional view of a protective film according to some embodiments of the present invention.

[0022] Reference numerals

[0023] 100, protective diaphragm; 200, supporting diaphragm;

[0024] 110, diaphragm body; 120, support layer; 130, electrode layer;

[0025] 1100, a first diaphragm body layer; 1200, a second diaphragm body layer; 1300, a third diaphragm body layer. DETAILED DESCRIPTION

[0026] The exemplary embodiments of the present invention will be described in more detail below with reference to specific embodiments. It should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0028] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0029] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0031] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0032] In the description of the embodiments of the present invention, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention.

[0033] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0034] In nuclear power plant equipment, valves are only accessories, but their role cannot be ignored, because valves play an extremely important role in the normal, safe and reliable operation of nuclear power plants. Due to the large amount and wide range of valves used in nuclear power plant equipment, it can be said that almost every system in a nuclear power plant cannot do without valves. For example, a pressurized water reactor nuclear power plant with two million-kilowatt units requires about 30,000 valves. Although the investment in valves accounts for about 2% of the total investment in nuclear power plants, the annual maintenance cost of valves in nuclear power plants accounts for more than half of the total maintenance cost.

[0035] As one of the many valves, the regulating valve is mainly used to ensure the automation of nuclear power plants. It requires a large amount of adjustment. Its main function is to maintain some conventional regulated parameters such as flow, pressure, temperature, water level, etc. with a certain accuracy. The diaphragm and the valve core are connected by a mechanical structure. One side of the diaphragm is the outlet pressure, and the other side is the reference pressure. When the two are equal, the diaphragm does not move; when the two are unbalanced, the diaphragm drives the valve core to move, and the valve core changes the opening at the valve core after movement, so that the two forces are balanced.

[0036] During the large amount of reciprocating motion of the valve core, the diaphragm will experience fatigue fracture failure in the local stress concentration area. Once the diaphragm fails, the regulating valve will soon stop working properly, causing the entire link to be paralyzed, which causes great trouble to the repair personnel. It is urgent to obtain a solution for the safety diaphragm to realize the prediction of the working state of the valve.

[0037] The present invention designs the regulating valve diaphragm with the highest probability of failure, so that the regulating valve can predict the failure of the working diaphragm in advance, and through the setting of the electrode layer in the protective diaphragm, the resistance value change of the electrode layer is monitored in real time by using monitoring equipment, and a signal or early warning is sent to the on-site staff. At the same time, the protective diaphragm can continue to provide the valve with air pressure opening and closing functions for a certain period of time, so that the valve can work normally, and maintenance personnel can have enough time to inquire about the valve position, stop the operation of the entire power supply system in advance, and quickly replace the diaphragm, thereby avoiding the sudden burst of the supporting diaphragm and causing a major accident in the nuclear power supply system.

[0038] The present invention provides a safety protection diaphragm for valve failure warning, such as Figure 1 As shown, the safety protection film includes a supporting film 200 and a protective film 100 overlapped with the supporting film 200. The protective film 100 and the supporting film 200 can be connected together by bonding or sewing. An electrode layer 130 is arranged inside the protective film 100. The protective film 100 is externally connected to a monitoring device to monitor the resistance value change of the electrode layer 130 through the monitoring device and determine whether the film has failed.

[0039] In the embodiment of the present invention, the protective diaphragm 100 and the supporting diaphragm 200 are used in combination. The supporting diaphragm 200 can be understood as a basic diaphragm. During normal operation, the supporting diaphragm 200 bears the main air pressure load, and the protective diaphragm 100 moves with the supporting diaphragm 200, and does not bear the air pressure load at this time. When the supporting diaphragm 200 fails, the protective diaphragm 100 is subjected to the air pressure, and the entire diaphragm expands, causing the internal strain to increase. Since the protective diaphragm 100 is connected to an external monitoring device, the resistance value change of the electrode layer 130 is monitored by the monitoring device to determine whether the diaphragm has failed. For example, when the protective diaphragm 100 is subjected to the air pressure, the entire diaphragm expands, causing the internal strain to increase, and the electrode layer 130 will break or rupture. At this time, the staff will receive a signal indicating that the supporting diaphragm 200 has failed and the diaphragm needs to be replaced, which realizes the valve's predicted diaphragm failure function. At the same time, the protective diaphragm 100 itself has the ability to continue to provide the valve with the opening and closing function for a certain period of time, providing the staff with sufficient maintenance and replacement time.

[0040] In the embodiment of the present invention, the rigidity of the supporting diaphragm 200 is greater than that of the protective diaphragm 100. Thus, the supporting diaphragm 200 with large rigidity bears the main air pressure load during normal operation, and the protective diaphragm 100 with small rigidity moves with the supporting diaphragm 200 and does not bear the air pressure load at this time. When the supporting diaphragm 200 fails, the protective diaphragm 100 with small rigidity is affected by the air pressure, and the entire diaphragm expands, increasing the internal strain.

[0041] In some embodiments of the present invention, the material of the supporting membrane 200 may be but is not limited to rubber, for example, it may be a rubber membrane in the prior art.

[0042] like Figure 2 As shown, the protective diaphragm 100 includes a diaphragm body 110 and a support layer 120 and an electrode layer 130 arranged inside the diaphragm body 110. The support layer 120 and the electrode layer 130 are stacked at intervals along the thickness direction of the diaphragm body 110. It can be understood that the support layer 120 and the electrode layer 130 are independently arranged inside the diaphragm body 110, and the two are stacked along the thickness direction of the diaphragm body 110 with a certain distance between them. As two functional layer structures inside the diaphragm body 110, the electrode layer 130 is used for external monitoring equipment to monitor the resistance value change of the electrode layer 130 through the monitoring equipment and determine whether the diaphragm has failed.

[0043] In an embodiment of the present invention, the support layer 120 disposed inside the diaphragm body 110 can play a supporting role when the protective diaphragm 100 works normally, and the electrode layer 130 disposed inside the diaphragm body 110 and cooperating with the support layer 120 can play a supporting role and continue to work when the support layer 120 is broken, and the electrode layer 130 is connected to a monitoring device, and the resistance value change of the electrode layer 130 is monitored by the monitoring device. When the electrode layer 130 is broken, its resistance value will change, and a signal will be sent to the system, indicating that the protective diaphragm 100 needs to be replaced in time, so that the staff can monitor the working status of the protective diaphragm 100 in real time and determine whether it has failed, so as to quickly locate and query the corresponding valve.

[0044] In some implementations, the time point at which the protective film 100 needs to be replaced can be determined by presetting the change in resistance value according to actual application requirements, so as to better reserve replacement time for the staff and make emergency preparations.

[0045] In the embodiment of the present invention, the stiffness of the electrode layer 130 is less than the stiffness of the support layer 120. Therefore, by arranging the support layer 120 and the electrode layer 130 with different stiffness inside the diaphragm body 110, the support layer 120 with large stiffness mainly plays a bearing function and is used to play a supporting role, while the electrode layer 130 with small stiffness is used to bear the deformation function after the functional layer fails, and can also play a supporting role when the support layer 120 is broken, and the electrode layer 130 with small stiffness is connected to the monitoring device to monitor the change of its resistance value through the monitoring device, so that the rupture of the electrode layer 130 can be discovered in time. For example, when the monitoring device detects that the resistance value of the electrode layer 130 changes, it indicates that the diaphragm as a whole has issued a failure alarm before it cannot work normally, indicating that the safety protection diaphragm needs to be replaced, and at the same time, it also buys time for the staff to prepare for emergencies in advance, reduces the adverse effects caused by valve failure, and saves time and energy for valve maintenance.

[0046] In an embodiment of the present invention, the electrode layer 130 is formed by weaving conductive yarn and non-conductive yarn so that the conductive yarn can be stretched simultaneously with the non-conductive yarn. The conductive yarn is used to connect the electrode leads to the external monitoring device.

[0047] In some embodiments of the present invention, the electrode layer 130 is an integrated fabric formed by interweaving conductive yarns and non-conductive yarns, wherein parameters such as fabric area and thickness can be independently designed according to actual applications, without specific limitations, so long as the resistance value change of the electrode layer can be sensitively monitored.

[0048] In an embodiment of the present invention, the support layer 120 is formed by weaving non-conductive yarns.

[0049] In some embodiments of the present invention, the support layer 120 is an integrated fabric formed by interweaving non-conductive yarns and non-conductive yarns. The fabric area and thickness and other parameters can be independently designed according to the actual application, without specific limitation, so as to play an effective supporting role when the protective film is working normally.

[0050] In the embodiment of the present invention, the conductive yarn may be, but is not limited to, silver-plated nylon conductive yarn. For example, the conductive yarn may be made of a conductive material such as a metal material, a carbon material, a conductive polymer, and a conductive oxide. In some embodiments, yarns made of conductive materials such as silver-plated, copper-plated, aluminum-plated, nickel-plated, and copper-nickel-plated are used.

[0051] In the embodiment of the present invention, the non-conductive yarn may be, but is not limited to, polyester yarn. For example, the non-conductive yarn may be a fiber material such as polyethylene, polypropylene, polyimide, polyacrylonitrile, polytetrafluoroethylene, polyamide, and polyester fiber.

[0052] In the embodiment of the present invention, two electrode leads respectively connected to the electrode layer 130 and the monitoring device are provided on the diaphragm body 110, thereby realizing the connection between the electrode layer 130 and the monitoring device and monitoring the resistance value change of the electrode layer 130 in real time.

[0053] Exemplarily, two terminals are provided at the upper edge of the diaphragm body 110, which serve as two electrodes of the electrode layer 130. After the conductive yarns are woven, the two electrodes are used to connect all the conductive yarns. The resistance between the two electrodes is monitored by a monitoring device, and the damage of the diaphragm is transmitted to the staff according to the resistance of the electrode layer 130. For example, when the conductive yarn breaks in the electrode layer 130, the resistance between the two electrodes will change. After the monitoring device detects the change, it transmits the signal to the staff system.

[0054] like Figure 1 As shown, the diaphragm body 110 includes a first diaphragm body layer 1100, a second diaphragm body layer 1200 and a third diaphragm body layer 1300 stacked in sequence along its thickness direction, the electrode layer 130 is located between the first diaphragm body layer 1100 and the second diaphragm body layer 1200, and the support layer 120 is located between the second diaphragm body layer 1200 and the third diaphragm body layer 1300.

[0055] In an embodiment of the present invention, the diaphragm body 110 can adopt a stacked structure, such as using a first diaphragm body layer 1100, a second diaphragm body layer 1200 and a third diaphragm body layer 1300 to be stacked layer by layer in sequence along the thickness direction, and the electrode layer 130 is placed between the first diaphragm body layer 1100 and the second diaphragm body layer 1200, and the support layer 120 is placed between the second diaphragm body layer 1200 and the third diaphragm body layer 1300, and finally pressed to form the overall structure of the protective diaphragm 100.

[0056] In the embodiment of the present invention, the material of the diaphragm body 100 may be but is not limited to rubber. For example, the material of the first diaphragm body layer 1100, the second diaphragm body layer 1200 and the third diaphragm body layer 1300 are all rubber.

[0057] In an embodiment of the present invention, the monitoring device includes a resistance sensor, which is connected to the electrode layer 130 and is used to monitor the change in the resistance value of the electrode layer 130. Since the allowable strain of the conductive yarn or conductive wire is small, when the electrode layer 130 with low stiffness plays a supporting role, it is affected by the air pressure, and the strain of the entire diaphragm will increase, which causes the conductive yarn to break. When the conductive yarn breaks in the electrode layer 130, the resistance value monitored by the resistance sensor changes, and the change is sent to the staff through a signal, thereby indicating that the support layer 120 with high stiffness has failed and the entire diaphragm needs to be replaced, thereby realizing the valve's function of predicting diaphragm failure.

[0058] In the embodiment of the present invention, in addition to predicting and judging whether the safety protection diaphragm has failed by the change in the resistance value of the electrode layer 130 as mentioned above, it is also possible to predict and judge whether the safety protection diaphragm has failed by precisely monitoring the air pressure.

[0059] In some embodiments of the present invention, the monitoring device includes an air pressure sensor, which is used to monitor the change of the air pressure value of the safety protection diaphragm and determine whether the diaphragm fails.

[0060] For example, since the stiffness of the supporting diaphragm 200 and the protective diaphragm 100 is different, the large deformation of the protective diaphragm 100 with small stiffness can be relied on to cause a significant increase in gas flow to predict whether the diaphragm has failed, rather than being limited to relying entirely on the resistance sensor for judgment. That is, the supporting diaphragm 200 has large stiffness, and the gas flow required for each cycle of valve opening and closing is small. After the supporting diaphragm 200 fails, the protective diaphragm 100 comes into play, the diaphragm deforms more, produces a greater expansion, and the gas flow will also fluctuate greatly. This fluctuation in gas flow transmits a signal to the staff through the air pressure sensor to achieve a pre-alarm.

[0061] For example, in some practical applications, considering the limitations of various application factors, the electrode layer with conductive yarn may not be used in the protective diaphragm 100 with low rigidity, and the large deformation of the protective diaphragm 100 with low rigidity causes fluctuations in air pressure to predict whether the diaphragm has failed. That is, the supporting diaphragm 200 has high rigidity, and the gas flow rate required for each cycle of valve opening and closing is small. After the supporting diaphragm 200 fails, the protective diaphragm 100 comes into play, the diaphragm deforms more, produces greater expansion, and the gas flow rate will also fluctuate greatly. This fluctuation in gas flow rate transmits a signal to the staff through the air pressure sensor to achieve a pre-alarm.

[0062] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A safety protection diaphragm for valve failure warning, characterized in that: The safety protection film comprises a supporting film and a protection film overlapped with the supporting film. An electrode layer is arranged inside the protective diaphragm, and a monitoring device is externally connected to the protective diaphragm to monitor the change of the resistance value of the electrode layer through the monitoring device and determine whether the diaphragm fails.

2. The safety protection diaphragm for valve failure warning according to claim 1, characterized in that: The rigidity of the supporting membrane is greater than the rigidity of the protecting membrane.

3. The safety protection diaphragm for valve failure warning according to claim 1 or 2, characterized in that: The protective diaphragm comprises a diaphragm body and a support layer arranged inside the diaphragm body. The support layer and the electrode layer are stacked and arranged with intervals along the thickness direction of the diaphragm body. The electrode layer is externally connected to a monitoring device.

4. The safety protection diaphragm for valve failure warning according to claim 3, characterized in that: The stiffness of the electrode layer is smaller than the stiffness of the support layer.

5. The safety protection diaphragm for valve failure warning according to claim 1, characterized in that: The electrode layer is formed by weaving conductive yarn and non-conductive yarn, and the conductive yarn is used to connect electrode leads to external monitoring equipment; and / or, The support layer is formed by weaving non-conductive yarn.

6. The safety protection diaphragm for valve failure warning according to claim 5, characterized in that: The conductive yarn comprises silver-plated nylon conductive yarn; and / or, The non-conductive yarn includes polyester yarn.

7. The safety protection diaphragm for valve failure warning according to claim 3, characterized in that: The diaphragm body includes a first diaphragm body layer, a second diaphragm body layer and a third diaphragm body layer which are stacked in sequence along the thickness direction thereof. The electrode layer is located between the first diaphragm body layer and the second diaphragm body layer, and the support layer is located between the second diaphragm body layer and the third diaphragm body layer.

8. The safety protection diaphragm for valve failure warning according to claim 1, characterized in that: The material of the supporting diaphragm includes rubber; Preferably, the material of the diaphragm body includes rubber.

9. The safety protection diaphragm for valve failure early warning according to claim 1, characterized in that: The monitoring device includes a resistance sensor connected to the electrode layer.

10. The safety protection diaphragm for valve failure warning according to claim 1, characterized in that: The monitoring device includes an air pressure sensor for monitoring the change of the air pressure value of the safety protection diaphragm and determining whether the diaphragm fails.

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