Pressure exchanger
By introducing a piston braking system and a pressure relief device into the pressure exchanger, the problem of piston wear and energy loss caused by impacting the valve plate under high pressure is solved, achieving pressure exchange with low wear and high energy efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DANFOSS AS
- Filing Date
- 2022-04-19
- Publication Date
- 2026-05-19
AI Technical Summary
Existing pressure exchangers are prone to wear due to impacts on the valve plate during piston movement, and have low energy efficiency, especially with significant energy loss when operating under high pressure conditions.
The system employs a piston braking system and a pressure relief device, including a thrust washer, a tapered section, and a pressure relief channel. This reduces wear between the piston and cylinder through buffering and lubrication, and releases excess pressure under high pressure to prevent piston damage.
It effectively reduces wear on the piston and cylinder, improves energy efficiency, reduces maintenance requirements, and prevents damage caused by high-pressure peaks.
Smart Images
Figure CN115704406B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a pressure exchanger having a valve system comprising a cylinder, two valve plates and two port plates, wherein the cylinder comprises at least one cylinder that accommodates a piston. Background Technology
[0002] The cylinder is arranged along the longitudinal direction of the cylinder barrel, thereby achieving fluid connection between the two longitudinal surfaces of the cylinder barrel. A valve plate is arranged on the first side of each surface of the cylinder barrel, while a port plate is arranged on the second side of each valve plate. The cylinder barrel rotates relative to the port plates.
[0003] One port plate is a first port plate, and the other port plate is a second port plate. Each of the first and second port plates includes two openings. Pressure is applied to the first opening of the first port plate, causing a piston in at least one cylinder to move from a first end position near the first port plate to a second end position near the second port plate. Therefore, fluid in the cylinder is forced out through the first opening of the second port plate.
[0004] The cylinder rotates, causing it to interact with the second opening of the first port plate and the second opening of the second port plate. Because the second opening of the second port plate applies fluid pressure to the cylinder, the piston is pushed from the second end position to the first end position, thereby forcing the fluid in the cylinder through the second opening of the first port plate.
[0005] The cylinder rotates further until it interacts with the first opening of the first port plate and the first opening of the second port plate. The process then restarts.
[0006] Depending on the cylinder pressure ratio and rotational speed, the piston may strike the valve plate each time it moves from one end position to another, leading to wear and downtime due to maintenance. Furthermore, the sudden stop of the piston results in energy loss, as its kinetic energy should be used to move the fluid, leading to low energy efficiency. Summary of the Invention
[0007] The problem to be solved by the present invention is to provide a pressure exchanger with low wear and high energy efficiency.
[0008] This problem is solved by the features of the pressure exchanger according to the present invention.
[0009] The pressure exchanger includes a piston braking system, and the piston includes a pressure relief device. The piston braking system allows the piston speed at one of its end positions to be reduced to prevent it from exceeding speed limits and potentially impacting the valve plate, causing damage. However, this can lead to an increase in cylinder pressure (even pressure spikes), which could damage the piston or cylinder. To compensate for pressure spikes, the piston is equipped with a pressure relief device. This device allows for the reduction of overpressure, thereby preventing damage to the pressure exchanger.
[0010] The primary task of a pressure exchanger is to exchange pressure between two fluids, one with a high pressure level and the other with a low pressure level, wherein the fluids may be different from each other. The pressure exchanger transfers pressure energy from the high-pressure fluid to the low-pressure fluid. Pressure exchangers are used, for example, in processes operating at elevated pressure levels and with a high-pressure waste flow, such that the high pressure level of the waste flow is transferred to the input flow for the elevated pressure level. Such pressure exchangers are used, for example, in reverse osmosis systems, where the pressure exchanger can be placed at a connection point away from the output side of the reverse osmosis membrane, where the pressure level is relatively high, allowing some of that pressure to be used in the input flow to the reverse osmosis membrane.
[0011] Alternatively, a pump or motor can be used for pressure exchangers.
[0012] Pistons are made of lightweight materials such as plastic. Lightweight materials allow for a gentler impact at the end, thus reducing wear.
[0013] In one embodiment, the piston is arranged to float within the cylinder. The floating piston allows for a predetermined fluid connection between each side of the cylinder, which is separated by the piston. Furthermore, the floating arrangement allows for piston lubrication, resulting in lower wear on both the piston and the cylinder, thus enabling low-maintenance operation.
[0014] In one embodiment, the piston braking system includes at least one thrust pad forming a chamber between the cylinder and the valve plate. Preferably, the thrust pad is fixed in the valve plate, and a hydraulic flexible seal is provided to seal the thrust pad and the cylinder within the cylinder. Each of at least one cylinder is provided with a thrust pad. This allows for gentle impacts to the piston, while the chamber provides lubrication for the piston.
[0015] The thrust washer can be formed from, for example, super duplex steel. Furthermore, the thrust washer can be coated, for example, with a wear-resistant material that interacts well with the piston material, such as DLC, PEE, etc. Alternatively, the material of the thrust washer can be adjusted to the piston material or other materials, such that the interaction between the piston and the thrust washer results in low wear, thereby achieving low-maintenance operation.
[0016] In one embodiment, the thrust washer protrudes radially inward relative to the inner surface of the cylinder. Therefore, the piston can be slowed down by striking the thrust washer on the side facing the direction of movement. This allows the piston to stop at a predetermined position.
[0017] In one embodiment, the piston includes at least one tapered portion. The tapered portion is disposed at one end of the piston along the direction of movement. The tapered portion interacts with a thrust washer and a formed chamber, thereby forming a fluid pad within the chamber. This fluid pad is pressurized when the piston reaches its end position, thereby decelerating the piston. Furthermore, the tapered portion forces fluid around the piston, thus creating good lubrication between the piston and the cylinder. Additionally, the tapered portion allows for easy assembly of the pistons into the cylinder because they are self-centering.
[0018] In one embodiment, at the end position of the piston within the cylinder, the chamber is at least partially sealed by a tapered section. Preferably, the thrust washer and valve plate are press-fitted for sealing, and the thrust washer and cylinder are sealed with an O-ring. Therefore, fluid in the chamber can only escape through the gap formed between the thrust washer, cylinder, and piston. Deceleration is determined based on the increase in pressure within the chamber. This achieves effective piston stopping.
[0019] In one embodiment, the central portion of the piston is formed as a cylinder with two sides facing the longitudinal direction of the cylinder, wherein the pressure relief device includes at least a temporary fluid connection between the two sides of the piston. This arrangement allows overpressure on one side of the piston to be released to the other side. As a result, peak pressure decreases rapidly without damaging any components of the pressure exchanger.
[0020] In one embodiment, the pressure relief device includes at least one cavity disposed inside the piston, wherein the cavity is fluidly connected to both sides of the piston. The cavity itself acts as a buffer, trapping fluid from the overpressure side and thereby reducing the mixing of fluids from both sides of the piston.
[0021] When the pressure exchanger is not in operation with the piston, the two fluids are in physical contact, causing them to mix. Due to the piston's pressure relief system, the mixing of the fluids is less, thus improving the efficiency of the pressure exchanger.
[0022] In one embodiment, at least one cavity is filled with a sponge-like material. The cavity containing the sponge-like material also serves as a buffer. The sponge-like material describes any material capable of absorbing fluids, preferably a porous material such as ceramic. Fluid exchange is minimal because the sponge-like material absorbs the liquid slowly.
[0023] In one embodiment, the pressure relief device includes at least one pressure relief channel. At least one pressure relief channel is a simple and cost-effective measure to release overpressure from the high-pressure side of the piston to the low-pressure side.
[0024] In one embodiment, the pressure relief device includes at least one valve. This valve may be, for example, an overpressure valve, wherein the set pressure can be selected based on the pressure ratio and other characteristics of the pressure exchanger.
[0025] In one embodiment, the pressure relief device includes at least one pressure relief channel, at least one valve, at least one cavity, and at least one cavity filled with a sponge-like material, or a combination thereof. This allows for precise adjustment of the pressure relief device, resulting in minimal pressure loss.
[0026] In one embodiment, the tapered portion is an annular protrusion projecting from the center of the piston. This allows for adjustment of the piston's internal design. The dimensions of the pressure relief passages, valves, and / or cavities can be adjusted without altering the piston's external dimensions. Therefore, the piston can be easily adapted to any desired configuration.
[0027] In addition, the annular protrusion reduces weight and improves the efficiency of the pressure exchanger. Attached Figure Description
[0028] The invention will now be described in more detail with reference to the accompanying drawings, in which:
[0029] Figure 1 The internal components of the pressure exchanger are shown;
[0030] Figure 2 A first embodiment of the piston is shown;
[0031] Figure 3 A second embodiment of the piston is shown;
[0032] Figure 4 A third embodiment of the piston is shown;
[0033] Figure 5 A fourth embodiment of the piston is shown;
[0034] Figure 6 A piston braking system is shown in which the piston is positioned near its end.
[0035] Figure 7 A piston braking system is shown in which the piston is in the end position. Detailed Implementation
[0036] Figure 1 The image depicts a cylinder 1, a valve plate 2, a first port plate 3, and a second port plate 4. The valve plate 2 is sandwiched between the cylinder 1 and either the first port plate 3 or the second port plate 4. The cylinder 1 and the valve plate 2 are arranged to rotate relative to the first port plate 3 and the second port plate 4.
[0037] The first port plate 3 includes a first opening 5 and a second opening 6. The second port plate 4 also includes a first opening and a second opening, neither of which is shown.
[0038] The cylinder 1 includes a plurality of cylinders 7, each cylinder 7 housing a movable and floating piston 8. The piston 8 includes a first side facing the first port plate 3 and a second side facing the second port plate 4. The piston 8 can move from a first end position near the first port plate 3 to a second end position near the second port plate 4 according to the pressure difference between the first opening 5 of the first port plate 3 and the first opening of the second port plate 4.
[0039] As cylinder 1 rotates, starting from the first end position of piston 8, a first pressurized fluid is applied to the first side of piston 8 through the first opening 5 of the first port plate 3, causing piston 8 to move to the second end position. As a result, a second fluid on the second side of piston 8 in cylinder 7 is transferred through the first opening of the second port plate 4.
[0040] When piston 8 reaches the second end position, cylinder 7 interacts with the second opening 6 of first port plate 3 and the second opening of second port plate 4. Second fluid is transferred into cylinder 7 to interact with the second side of piston 8, moving piston 8 from the second end position to the first end position, so that the first fluid in cylinder 7 is transferred through the second opening 6 of first port plate 3.
[0041] This allows pressure to be transferred from the first fluid to the second fluid.
[0042] If the piston 8 stops rapidly or suddenly, and the pressure peak is too high or not released within a predetermined time period, the applied pressure may deform or damage the piston 8. To avoid damage to the piston 8, the piston 8 includes a pressure relief device that allows the peak pressure or overpressure to be reduced from the first side of the piston 8 to the second side of the piston 8 or vice versa.
[0043] exist Figures 2 to 5 The image depicts a piston 8 including a pressure relief device. The pressure relief device allows at least temporary fluid communication between the two sides of the piston 8. Overpressure can be discharged from the high-pressure side of the piston 8 to the low-pressure side.
[0044] exist Figure 2 In the piston 8, multiple pressure relief channels 9 are included, which allow fluid communication between the two sides of the piston 8. The pressure relief channels 9 can be designed according to the pressure ratio between the two sides of the piston 8, the viscosity of the first fluid and the second fluid, the maximum peak pressure of the pressure exchanger, and / or other characteristics. For example, the number of pressure relief channels 9, their diameter, and / or length can be adjusted.
[0045] Figure 3 A piston 8 with a valve 10 is depicted, which allows temporary fluid connection between the two sides of the piston. The valve 10 may be, for example, an overpressure valve. Once a predetermined set value is exceeded, the valve 10 opens, thereby preventing damage to the piston 8.
[0046] Figure 4 A piston 8 is depicted having a cavity 11 and a fluid communication portion 12 on each side of the piston 8, the fluid communication portion 12 allowing fluid communication between the cavity 11 and fluid on either side of the piston 8. The cavity 11 essentially acts as a buffer, allowing a first fluid and a second fluid to mix. Due to its buffering effect, only a small amount of the mixture of the first and second fluids is carried into the fluid outside the piston 8.
[0047] exist Figure 5 In the cylinder 7, the cavity 11 is filled with a sponge-like material 13 that allows fluid communication with either side of the piston 8 via the fluid communication section 12. The sponge-like material slows down the mixing between the two fluids, resulting in lower fluid mixing in the cylinder 7. The sponge-like material 13 may be composed of a porous material (e.g., ceramic).
[0048] Figure 6 and Figure 7 A pressure exchanger with a piston braking system and a pressure relief device is shown. A piston 8 is housed in a cylinder 7 having multiple pressure relief channels 9 forming the pressure relief device. Additionally, tapered portions 14 are arranged on both sides of the piston 8. The tapered portions 14 protrude annularly from the central portion 15 of the piston 8 in the longitudinal direction.
[0049] Regarding the piston braking system, a thrust pad 16 is disposed between the cylinder 1 and each valve plate 2. The thrust pad 16 protrudes radially inward relative to the inner surface of the cylinder 7. Thus, once the piston 8 approaches either end position, the tapered portion 14 of the piston 8 interacts with the thrust pad 16. A chamber 17 is formed between the inner surface of the cylinder 7, the thrust pad 16, and the tapered portion 14. Fluid supplied in the chamber 17 can overflow through the gaps between the thrust pad 16, the piston 8, the cylinder 1, and / or the valve plate 2.
[0050] The deceleration is determined by the increase in pressure within chamber 17. As piston 8 approaches its end position, the volume of chamber 17 decreases, and so does the clearance. Therefore, fluid in chamber 17 needs to overflow through the narrowing clearance 18, which requires increased pressure. This allows for a gradual cessation of piston 8 movement. The pressure increase can be adjusted to suit the demand by regulating the angle, length, and / or diameter of the tapered portion 14.
[0051] Alternatively, for piston 8, which includes pressure relief channel 9, Figure 7 The pressure relief device described herein may include Figures 3 to 5 At least one of the embodiments.
[0052] Another alternative is: a pressure relief device is Figures 2 to 5 The combination of embodiments depicted herein.
[0053] The combination of the piston braking system and the pressure relief device allows for a gentle stop of piston 8 while releasing overpressure. Therefore, the load on piston 8, cylinder 1, and valve plate 2 is reduced, resulting in less wear and thus better maintainability and efficiency.
[0054] List of reference numerals
[0055] 1. Cylinder
[0056] 2 Valve Plate
[0057] 3 First Port Board
[0058] 4 Second Port Board
[0059] 5. First opening of the first port board
[0060] 6. Second opening of the first port board
[0061] 7 cylinders
[0062] 8 pistons
[0063] 9. Pressure relief channel
[0064] 10 valves
[0065] 11. Cavity
[0066] 12. Fluid communication section
[0067] 13. Sponge-like materials
[0068] 14. Conical section
[0069] 15. Central Section
[0070] 16 Thrust Pads
[0071] 17 chambers.
Claims
1. A pressure exchanger having a valve system, said valve system comprising a cylinder (1), two valve plates (2) and two port plates (3, 4), wherein, The cylinder (1) includes at least one cylinder (7) that houses the piston (8). The pressure exchanger is characterized by comprising a piston (8) braking system, and the piston (8) comprising a pressure relief device. The piston (8) includes two opposite sides facing the cylinder (7) in the longitudinal direction, namely the first side and the second side. The pressure relief device is configured to allow the reduction of peak pressure or overpressure from the first side of the piston (8) to the second side of the piston (8) or vice versa.
2. The pressure exchanger according to claim 1, characterized in that, The piston (8) is arranged to float in the cylinder (7).
3. The pressure exchanger according to claim 1 or 2, characterized in that, The piston (8) braking system includes at least one thrust pad (16) that forms a chamber (17) between the cylinder (1) and the valve plate (2).
4. The pressure exchanger according to claim 3, characterized in that, The thrust pad (16) protrudes radially inward relative to the inner surface of the cylinder (7).
5. The pressure exchanger according to claim 3, characterized in that, The piston (8) includes at least one tapered portion (14).
6. The pressure exchanger according to claim 5, characterized in that, At the end position of the piston (8) within the cylinder (7), the chamber (17) is at least partially closed by the conical portion (14).
7. The pressure exchanger according to claim 1 or 2, characterized in that, The pressure relief device includes at least a temporary fluid connection between the two sides of the piston (8).
8. The pressure exchanger according to claim 1 or 2, characterized in that, The pressure relief device includes at least one cavity (11) arranged inside the piston (8), wherein the cavity (11) is fluidly connected to both sides of the piston (8).
9. The pressure exchanger according to claim 1 or 2, characterized in that, The pressure relief device includes at least one cavity (11) filled with a sponge-like material (13), wherein the cavity (11) is fluidly connected to both sides of the piston (8).
10. The pressure exchanger according to claim 1 or 2, characterized in that, The pressure relief device includes at least one pressure relief channel.
11. The pressure exchanger according to claim 1 or 2, characterized in that, The pressure relief device includes at least one valve (10).
12. The pressure exchanger according to claim 1 or 2, characterized in that, The pressure relief device includes: at least one pressure relief channel, at least one valve, at least one cavity, and at least one cavity filled with a sponge-like material, or a combination thereof.
13. The pressure exchanger according to claim 5, characterized in that, The at least one tapered portion (14) is an annular protrusion that protrudes from the center portion of the piston (8).