Secondary temperature control system, dialysis system and temperature control method of CRRT equipment

Abstract

The present invention discloses a secondary temperature control system for CRRT equipment, including a primary temperature control unit and a secondary temperature control unit; the primary temperature control unit includes a primary container, a primary temperature control actuator and a primary flow pump, the primary container is used to accommodate a liquid bag, the primary temperature control actuator is used to adjust the temperature of the liquid in the liquid bag, and the liquid temperature is within a set preheating temperature range; the primary flow pump is used to pump the preheated liquid into the secondary temperature control unit according to a set flow rate; the secondary temperature control unit includes a secondary container, a secondary temperature control actuator and a secondary flow pump, the secondary container is used to accommodate a liquid bag, the secondary temperature control actuator is used to adjust the temperature of the liquid in the secondary container, and the liquid temperature is within a set target temperature range; the secondary flow pump is used to pump the temperature-controlled liquid out of the secondary container according to a set flow rate. The present invention also discloses a secondary temperature control method for a dialysis system and a CRRT equipment, which uses a secondary temperature control system to accurately control the liquid temperature.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically a two-stage temperature control system, dialysis system, and temperature control method for CRRT equipment. Background Technology

[0002] Continuous blood purification (CRRT) equipment is used for blood purification treatment of critically ill patients, with treatment times generally exceeding 8 hours and sometimes lasting for several days. The treatment process consumes a large amount of dialysate / replacement fluid. Studies have shown that patients are prone to hypothermia during treatment due to heat loss, leading to dysregulation of body temperature, which is extremely detrimental to stabilizing the patient's condition and can even result in serious consequences. Therefore, it is essential to warm the chilled or room-temperature dialysate / replacement fluid to near the patient's body temperature. Depending on the patient's condition, the target heating temperature for the treatment fluid is generally 33–39°C. The target heating temperature for the treatment fluid is set and adjusted according to the treatment prescription.

[0003] Currently, there are two main schemes for CRRT equipment's dialysate / replacement fluid. The first scheme involves the liquid in the initial liquid packaging bag (dialysis fluid / replacement fluid bag) flowing into a heated fluid bag. A container with an openable door holds the fluid bag, and heating plates on both sides heat the bag. The inside of the fluid bag has an S-shaped fluid path. The heating plates directly heat the dialysate in the bag from 5-31℃ to 37℃-38℃ (human body temperature). Temperature sensors detect the temperature of the heating plates and the temperature at the outlet of the heated fluid bag, controlling the heating plate power based on the detected temperatures. The second scheme involves the liquid in the initial liquid packaging bag (dialysis fluid / replacement fluid bag) flowing into a fluid bladder. The fluid bladder is placed inside a semi-enclosed container. Heating wires on the inner wall of the semi-enclosed container heat the fluid bladder. A metal component contacts the outer wall of the fluid bladder to indirectly measure the temperature of the liquid inside.

[0004] Therefore, it can be seen that in the two existing main schemes, there is only one heat source providing heating and feedback control for the liquid bag / liquid bladder, and both belong to single-point heating control loops, such as... Figure 6 As shown, the liquid is heated from an initial temperature to a target temperature within a single heat source. Existing single-point heating control loops have the following shortcomings:

[0005] (1) When the liquid temperature is low, the heating plate will use high power to heat it. However, in the existing solution, the liquid temperature is measured by the sensor contacting the outer surface of the liquid bag, that is, the liquid temperature is measured indirectly through the liquid bag. There will be a long temperature lag time, which will cause the liquid to overheat easily, that is, the liquid temperature after heating exceeds the target temperature.

[0006] (2) When the liquid flow rate is large, due to the limited volume of the heating container, the fresh, low-temperature liquid does not receive sufficient heat exchange, resulting in a low outlet temperature. Experimental tests showed that when the target temperature was set at 37℃, the actual heating temperature of the two CRRT models currently used in clinical practice was only 33-34℃ (room temperature 27℃). The current equipment solutions cannot solve the problems of excessively low and overheating within the nominal flow rate range of the equipment.

[0007] like Figure 7 As shown, an experimental test was conducted on the temperature loss of a commercially available model at different flow rates. At a room temperature of 16℃, the temperature of the liquid in the liquid bag was close to 16℃. The liquid pump flow rate was set to 3ml / min and 5ml / min, and the corresponding liquid temperature at the heating plate temperature was measured. The measurement results show that increasing the flow rate leads to a decrease in the actual liquid temperature at the same heating plate temperature; and the maximum flow rate of the liquid pump can be set to 100ml / min, with higher flow rates easily leading to a greater deviation in the actual liquid temperature. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a two-stage temperature control system, a dialysis system and a temperature control method for a CRRT device, which can accurately control the liquid temperature by adopting a two-stage temperature control system.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] This invention first proposes a two-stage temperature control system for CRRT equipment, comprising a primary temperature control unit and a secondary temperature control unit;

[0011] The primary temperature control unit includes a primary container, a primary temperature control actuator, and a primary flow pump. The primary container is used to hold or place a liquid bag, and the primary temperature control actuator is used to regulate the liquid temperature T1 inside the liquid bag and keep the liquid temperature T1 within the set preheating target temperature zone [T]. 11 ,T 12 Within this range, the primary temperature control unit has a preheating temperature range [T]. 1a ,T 1b ], The primary flow pump is used to pump the preheated liquid into the secondary temperature control unit at a set flow rate.

[0012] The secondary temperature control unit includes a secondary container, a secondary temperature control actuator, and a secondary flow pump. The secondary container is used to hold a liquid bladder, which is used to collect the pumped liquid. The secondary temperature control actuator is used to regulate the liquid temperature T2 inside the liquid bladder and keep the liquid temperature T2 within the set target supply temperature range [T]. 21 ,T 22Within this range, the secondary temperature control unit has a target temperature range [T]. 2a ,T 2b ], The secondary flow pump is used to pump the temperature-adjusted liquid out of the liquid bladder at a set flow rate.

[0013] The maximum temperature value of the preheating temperature range is within the target temperature range, and the minimum temperature value of the target temperature range is within the preheating temperature range; or, the maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range; the secondary temperature control unit is used to heat the liquid and keep the liquid temperature within the target temperature range; or,

[0014] The minimum temperature value of the preheating temperature range is located within the target temperature range, and the maximum temperature value of the target temperature range is located within the preheating temperature range; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range; the secondary temperature control unit is used to cool the liquid and keep the liquid temperature within the target temperature range.

[0015] Furthermore, the maximum temperature value of the preheating temperature range is located within the target temperature range, and the minimum temperature value of the target temperature range is located within the preheating temperature range; or, the minimum temperature value of the preheating temperature range is located within the target temperature range, and the maximum temperature value of the target temperature range is located within the preheating temperature range.

[0016] The absolute value of the difference between the minimum temperature value of the target temperature range and the minimum temperature value of the preheating temperature is 2-3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum temperature value of the preheating temperature is 2-3℃.

[0017] Furthermore, the maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range, and the absolute value of the difference between the maximum temperature value of the preheating temperature range and the minimum temperature value of the target temperature is less than 3°C; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range, and the absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature is less than 3°C.

[0018] Furthermore, the primary temperature control unit also includes a first temperature sensor disposed at the outlet of the primary container or liquid bag and a second temperature sensor disposed on the primary temperature control actuator; the first temperature sensor is used to measure the liquid temperature inside the liquid bag, and the second temperature sensor is used to measure the temperature of the primary temperature control actuator.

[0019] Furthermore, the primary temperature control unit also includes a primary temperature control unit. This primary temperature control unit receives temperature data measured by the first and second temperature sensors and controls the output power of the primary temperature control actuator. The principle is as follows:

[0020]

[0021] Where: U1(t) is the output power of the first-stage temperature control actuator; kp1 is the first proportional coefficient; T I T is the first integral time constant; D Let be the first differential time constant; t be time; err1(t) be the PID feedback regulation deviation of the first-stage temperature control unit, and:

[0022] err1(t)=r1(t)―y1(t)

[0023] Where: r1(t) is the liquid temperature in the liquid bag measured by the first temperature sensor; y1(t) is the temperature of the first-stage temperature control actuator measured by the second temperature sensor.

[0024] Furthermore, the secondary temperature control unit also includes a third temperature sensor disposed at the liquid outlet of the liquid bladder and a fourth temperature sensor disposed on the secondary temperature control actuator; the third temperature sensor is used to measure the liquid temperature inside the liquid bladder, and the fourth temperature sensor is used to measure the temperature of the secondary temperature control actuator.

[0025] Furthermore, the secondary temperature control unit also includes a secondary temperature control unit. This control unit receives temperature data measured by the third and fourth temperature sensors and controls the output power of the secondary temperature control actuator. The principle is as follows:

[0026]

[0027] Where: U2(t) is the output power of the secondary temperature control actuator; kp2 is the second proportional coefficient; T′ I T′ is the second integral time constant; D Let be the second derivative time constant; t be time; err2(t) be the PID feedback adjustment deviation of the secondary temperature control unit, and:

[0028] err2(t)=r2(t)―y2(t)

[0029] Where: r2(t) is the liquid temperature inside the liquid bladder measured by the third temperature sensor; y2(t) is the temperature of the secondary temperature control actuator measured by the fourth temperature sensor.

[0030] Furthermore, the secondary temperature control unit also includes a secondary temperature control unit. The secondary temperature control unit receives the temperature data measured by the third temperature sensor, and sets and maintains the heating temperature of the secondary temperature control actuator according to the set target temperature and flow rate of the liquid supplied from the secondary temperature control unit to the downstream end, until the set target temperature and / or flow rate of the liquid supply changes. Then, the secondary temperature control unit resets the heating temperature of the secondary temperature control actuator and maintains it stable.

[0031] The present invention also proposes a dialysis system, including a dialyzer, wherein the dialyzer is provided with a blood inlet, a blood outlet, a dialysate inlet, and a waste liquid outlet, wherein the blood inlet is connected to an arterial line, the blood outlet is connected to a venous line, the dialysate inlet is connected to a dialysate supply system, and / or, the arterial line and / or the venous line are provided with a replacement fluid inlet, the replacement fluid inlet is connected to a replacement fluid supply system, the dialysate supply system is provided with a dialysate temperature control system, and / or the replacement fluid supply system is provided with a replacement fluid temperature control system, wherein both the dialysate temperature control system and the replacement fluid temperature control system adopt the two-stage temperature control system of the CRRT equipment as described in any of the above claims.

[0032] This invention also proposes a two-stage temperature control method for CRRT equipment, wherein the equipment sets the target temperature zone [T] for the liquid supply according to the user-defined target temperature. 21 ,T 22 ] and the preheating target temperature zone [T 11 ,T 12 The temperature adjustment process includes the following steps:

[0033] Step S1: Place the liquid bag into the primary container;

[0034] Step S2: The primary temperature control unit detects the liquid temperature inside the liquid bag and makes a judgment based on the equipment's operating status: If the equipment's temperature control system is in the liquid supply preparation state, or if the equipment's temperature control system is in the liquid supply state but the liquid temperature inside the liquid bag exceeds the preheating safety temperature, then adjust the liquid bag temperature to the preheating target temperature zone [T]. 11 ,T 12 If the equipment temperature control system is in liquid supply mode and the liquid temperature in the liquid bag is within the preheating safe temperature limit, then proceed to step S3, and simultaneously adjust the liquid bag temperature to the preheating target temperature zone [T]. 11 ,T 12 ];

[0035] Step S3: Pump the liquid in the liquid bag into the liquid bladder in the secondary container at the set flow rate;

[0036] Step S4: The secondary temperature control unit detects the liquid temperature inside the liquid bladder and makes a judgment based on the equipment's operating status: If the equipment's temperature control system is in liquid supply preparation mode, or if the temperature control system is in liquid supply mode but the liquid temperature inside the liquid bladder exceeds the safe liquid supply temperature limit, then the liquid temperature inside the liquid bladder is adjusted to the target liquid supply temperature range [T]. 21 ,T 22 If the equipment temperature control system is in liquid supply mode and the liquid temperature in the liquid bladder is within the safe liquid supply temperature limit, then proceed to step S5, and simultaneously adjust the liquid temperature in the liquid bladder to the target liquid supply temperature range [T]. 21 ,T 22 ];

[0037] Step S5: Pump the liquid out of the liquid bladder according to the set flow rate.

[0038] Furthermore, adjust the temperature of the liquid bag to the preheating target temperature zone [T]. 11 ,T 12 The process is carried out according to steps S21 to S24:

[0039] Step S21: Use the first-stage temperature control actuator to adjust the temperature of the liquid in the liquid bag. After setting the unit time interval, execute step S22.

[0040] Step S22: Determine whether the liquid temperature T1 inside the liquid bag is within the set preheating target temperature range [T 11 ,T 12 If yes, proceed to step S24; otherwise, if the liquid temperature T1 in the liquid bag is less than the minimum temperature value T of the preheating target temperature zone... 11 Execute step S21; if the liquid temperature T1 in the liquid bag is greater than the maximum temperature value T of the preheating target temperature zone. 12 Proceed to step S23;

[0041] Step S23: Turn off the first-stage temperature control actuator, set the unit time interval, and then execute step S22;

[0042] Step S24: Determine whether the temperature difference between the primary temperature control actuator and the liquid temperature in the liquid bag is within the steady-state temperature error range: if yes, it indicates that the primary temperature control unit has reached a steady state, and proceed to step S2; if no, proceed to step S21.

[0043] Furthermore, adjust the temperature of the liquid inside the bladder to the target temperature range for liquid supply [T]. 21 ,T 22 The process is carried out according to steps S42 to S44:

[0044] Step S41: Determine whether the liquid temperature inside the liquid bladder is within the set target temperature range for liquid supply [T] 21 ,T 22If yes, proceed to step S44; otherwise, if the liquid temperature T2 inside the liquid bladder is less than the minimum temperature value T of the target temperature zone for liquid supply... 21 Furthermore, the secondary temperature control actuator is a heating device, or the liquid temperature T2 in the liquid bladder is greater than the maximum temperature value T of the target temperature zone for the liquid supply. 22 Furthermore, the secondary temperature control actuator is a cooling device, executing step S42; if the liquid temperature in the liquid bladder is greater than the maximum temperature value T of the target temperature zone for liquid supply. 22 Furthermore, the secondary temperature control actuator is a heating device, or the liquid temperature inside the liquid bladder is less than the minimum temperature value T of the target temperature zone for the liquid supply. 21 Furthermore, the secondary temperature control actuator is a cooling device, and performs step S43;

[0045] Step S42: Use the secondary temperature control actuator to adjust the temperature of the liquid in the liquid bladder. After setting the unit time interval, execute step S41.

[0046] Step S43: Turn off the secondary temperature control actuator, set the unit time interval, and then execute step S41;

[0047] Step S44: Determine whether the temperature difference between the secondary temperature control actuator and the liquid temperature in the liquid bladder is within the steady-state temperature error range: if yes, it indicates that the secondary temperature control unit has reached a steady state, and step S4 is executed; if no, step S41 is executed.

[0048] Furthermore, the maximum temperature value of the preheating temperature range is located within the target temperature range, and the minimum temperature value of the target temperature range is located within the preheating temperature range; or, the minimum temperature value of the preheating temperature range is located within the target temperature range, and the maximum temperature value of the target temperature range is located within the preheating temperature range.

[0049] The secondary temperature control unit is used to heat or cool the liquid and keep the liquid temperature within the target temperature range.

[0050] Furthermore, the absolute value of the difference between the minimum temperature value of the target temperature range and the minimum temperature value of the preheating temperature is 2-3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum temperature value of the preheating temperature is 2-3℃.

[0051] Furthermore, the maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range.

[0052] The secondary temperature control unit is used to heat or cool the liquid and keep the liquid temperature within the target temperature range.

[0053] Furthermore, the maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range, and the absolute value of the difference between the maximum temperature value of the preheating temperature range and the minimum temperature value of the target temperature is 2-3℃; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range, and the absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature is 2-3℃.

[0054] Furthermore, when the primary temperature control unit reaches a steady state, the temperature difference between the primary temperature control actuator and the liquid temperature inside the liquid bag is 3-4℃; when the secondary temperature control unit reaches a steady state, the temperature difference between the secondary temperature control actuator and the liquid temperature inside the liquid bladder is 3-4℃. Further, the primary temperature control unit also includes a first temperature sensor disposed at the outlet of the primary container or liquid bag and a second temperature sensor disposed on the primary temperature control actuator; the first temperature sensor is used to measure the liquid temperature inside the liquid bag, and the second temperature sensor is used to measure the temperature of the primary temperature control actuator.

[0055] Furthermore, the primary temperature control unit also includes a primary temperature control unit. This primary temperature control unit receives temperature data measured by the first and second temperature sensors and controls the output power of the primary temperature control actuator. The principle is as follows:

[0056]

[0057] Where: U1(t) is the output power of the first-stage temperature control actuator; kp1 is the first proportional coefficient; T I T is the first integral time constant; D Let be the first differential time constant; t be time; err1(t) be the PID feedback regulation deviation of the first-stage temperature control unit, and:

[0058] err1(t)=r1(t)―y1(t)

[0059] Where: r1(t) is the liquid temperature in the liquid bag measured by the first temperature sensor; y1(t) is the temperature of the first-stage temperature control actuator measured by the second temperature sensor.

[0060] Furthermore, the secondary temperature control unit also includes a third temperature sensor disposed at the liquid outlet of the liquid bladder and a fourth temperature sensor disposed on the secondary temperature control actuator; the third temperature sensor is used to measure the liquid temperature inside the liquid bladder, and the fourth temperature sensor is used to measure the temperature of the secondary temperature control actuator.

[0061] Furthermore, the secondary temperature control unit also includes a secondary temperature control unit. This control unit receives temperature data measured by the third and fourth temperature sensors and controls the output power of the secondary temperature control actuator. The principle is as follows:

[0062]

[0063] Where: U2(t) is the output power of the secondary temperature control actuator; kp2 is the second proportional coefficient; T′ I The second integral time constant; T′ D Let be the second derivative time constant; t be time; err2(t) be the PID feedback adjustment deviation of the secondary temperature control unit, and:

[0064] err2(t)=r2(t)―y2(t)

[0065] Where: r2(t) is the liquid temperature inside the liquid bladder measured by the third temperature sensor; y2(t) is the temperature of the secondary temperature control actuator measured by the fourth temperature sensor.

[0066] This invention also proposes a two-stage temperature control method for CRRT equipment, wherein the equipment sets the target temperature zone [T] for the liquid supply according to the user-defined target temperature. 21 ,T 22 ] and preheating target temperature zone [T 11 ,T 12 ]; wherein, the maximum temperature value T of the preheating target temperature zone 12 Less than or equal to the maximum value T of the set target temperature zone for liquid supply 22 ;

[0067] The temperature adjustment process includes the following steps:

[0068] Step S1: Place the liquid bag into the primary container;

[0069] Step S2: The primary temperature control unit detects the liquid temperature T1 in the liquid bag and makes a judgment based on the equipment's operating status: If the equipment's temperature control system is in the liquid supply preparation state, or the temperature control system is in the liquid supply state but the liquid temperature in the liquid bag exceeds the preheating safety temperature limit, then temperature control is performed according to steps S21 to S24; if the equipment's temperature control system is in the liquid supply state and the liquid temperature T1 in the liquid bag is within the preheating safety temperature limit, then step S3 is performed, and the temperature of the remaining liquid in the liquid bag is adjusted according to steps S21 to S24.

[0070] Step S21: Use the first-stage temperature control actuator to adjust the temperature of the liquid in the liquid bag. After setting the unit time interval, execute step S22.

[0071] Step S22: Determine whether the liquid temperature T1 inside the liquid bag is within the set preheating target temperature range [T 11 ,T 12 If yes, proceed to step S24; otherwise, if the liquid temperature T1 in the liquid bag is less than the minimum temperature value T of the preheating target temperature zone... 11 Execute step S21; if the liquid temperature T1 in the liquid bag is greater than the maximum temperature value T of the preheating target temperature zone. 12 Proceed to step S23;

[0072] Step S23: Turn off the first-stage temperature control actuator, set the unit time interval, and then execute step S22;

[0073] Step S24: Determine whether the difference between the temperature of the first-stage temperature control actuator and the liquid temperature T1 in the liquid bag is within the steady-state temperature error range: if yes, it indicates that the first-stage temperature control unit has reached a steady state, and proceed to step S3; if no, proceed to step S21.

[0074] Step S3: Pump the liquid in the liquid bag into the liquid bladder in the secondary container at the set flow rate;

[0075] Step S4: The secondary temperature control actuator of the secondary temperature control unit maintains the liquid bladder at the set heating temperature, and at the same time, judges the working status of the equipment: if the equipment temperature control system is in the liquid supply preparation state, then perform temperature detection and adjustment according to steps S41 to S42; if the equipment temperature control system is in the liquid supply state, then proceed to step S5, and perform temperature detection and adjustment according to steps S41 to S42.

[0076] Step S41: The secondary temperature control unit detects the liquid temperature T2 at the outlet of the liquid bladder and makes a judgment based on the pump flow rate: If the liquid temperature T2 at the outlet of the liquid bladder is not within the target temperature range for liquid supply [T 21 ,T 22 If the pump flow rate increases or decreases within the specified range, then step S42 is executed; if the liquid temperature value T2 at the liquid bladder outlet is within the target temperature zone for liquid supply, or the heating temperature set by the secondary temperature control actuator has reached the allowable limit, then the currently set heating temperature of the secondary temperature control actuator remains unchanged.

[0077] Step S42: Reset the heating temperature of the secondary temperature control actuator. After setting the unit time interval, execute step S41.

[0078] Step S5: Pump the liquid out of the liquid bladder according to the set flow rate.

[0079] Furthermore, for each set target liquid supply temperature, the heating temperature of the secondary temperature control actuator is allowed to be adjusted within a range of 2°C.

[0080] The beneficial effects of this invention are as follows:

[0081] The CRRT equipment two-stage temperature control system of the present invention comprises a primary temperature control unit and a secondary temperature control unit. A large-capacity liquid bag is placed in the primary container, and the primary temperature control actuator regulates the temperature of the liquid in the bag, bringing the primary temperature control unit to a steady state and maintaining the liquid temperature in the bag within a preheating temperature range close to the target temperature range. Then, the liquid in the bag is pumped into a liquid bladder at a set flow rate by a primary flow pump, and the secondary temperature control actuator regulates the temperature of the liquid in the bladder, keeping it within the target temperature range. Because the temperature of the liquid pumped into the secondary temperature control unit is already close to or within the target temperature range, the secondary temperature control unit can quickly reach a steady state at different flow rates, effectively preventing overheating and precisely controlling the temperature of the liquid pumped from the bladder. Attached Figure Description

[0082] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0083] Figure 1 This is a schematic diagram of the secondary temperature control system for CRRT equipment.

[0084] Figure 2 This is a schematic diagram of PID feedback control.

[0085] Figure 3 This is a schematic diagram of a dialysis system.

[0086] Figure 4 A flowchart of the first implementation of a two-stage temperature control method for CRRT equipment;

[0087] Figure 5 A flowchart illustrating a second implementation of a two-stage temperature control method for CRRT equipment;

[0088] Figure 6 The schematic diagram is of an existing single-point heating control loop;

[0089] Figure 7 This is a graph showing the relationship between the fluid flow rate and fluid temperature of a certain model of CRRT equipment used in clinical practice.

[0090] Explanation of reference numerals in the attached figures:

[0091] 10-First-stage temperature control unit; 11-First-stage container; 12-First-stage temperature control actuator; 13-First-stage flow pump; 14-First temperature sensor; 15-Second temperature sensor; 16-First-stage temperature control unit; 17-Liquid bag;

[0092] 20 - Secondary temperature control unit; 21 - Secondary container; 22 - Secondary temperature control actuator; 23 - Secondary flow pump; 24 - Third temperature sensor; 25 - Fourth temperature sensor; 26 - Secondary temperature control unit; 27 - Liquid bladder;

[0093] 30-Dialyzer; 31-Dialysis fluid supply system; 32-Replacement fluid supply system; 33-Arterial tubing; 34-Blood pump; 35-Waste fluid pump; 36-Waste fluid bag; 37-Intravenous tubing. Detailed Implementation

[0094] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0095] I. Secondary Temperature Control System for CRRT Equipment

[0096] During clinical CRRT treatment, healthcare professionals set the target temperature for the liquid heating system according to the treatment prescription. The permissible range for the target temperature is determined by the equipment manufacturer during the equipment design phase based on clinical needs and implemented through appropriate hardware and software.

[0097] like Figure 1 As shown, the CRRT equipment two-stage temperature control system of this embodiment includes a primary temperature control unit 10 and a secondary temperature control unit 20. The primary temperature control unit has a preheating temperature range [T]. 1a ,T 1b The secondary temperature control unit has a target temperature range [T]. 2a ,T 2b These are parameters determined by the device's hardware and software, reflecting the device's performance attributes. Among them, the target temperature range [T]... 2a ,T 2b The heating system operates normally within a user-defined target liquid supply temperature range, while the preheating temperature range [T] is... 1a ,T 1b [ ] is the allowable preheating temperature range for the liquid by the primary temperature control unit.

[0098] The target liquid supply temperature zone is a range of allowable deviations that can be manually set by the user or automatically generated by the equipment based on the user-set target liquid supply temperature. It serves as the temperature control reference for the secondary temperature control unit 20. Based on the set target liquid supply temperature, the user manually sets or the equipment automatically sets the preheating temperature value. At the same time, the equipment automatically generates a preheating temperature zone with a certain deviation from the set preheating temperature value, which serves as the temperature control reference for the primary temperature control unit 10.

[0099] As a safety control parameter, the supply fluid safe temperature limit refers to the temperature range that will not cause harm to the downstream fluid circuit or the patient. This temperature range includes the target temperature range. The supply fluid safe temperature limit is a safety temperature limit that needs absolute control and can therefore be reasonably set by the equipment manufacturer. When the fluid temperature exceeds the supply fluid safe temperature, the fluid supply system will not supply fluid to the downstream circuit, and the equipment can issue a prompt or alarm. The equipment preheating safe temperature limit is automatically generated by the equipment based on the set target temperature. It represents the safe temperature of the fluid after primary temperature adjustment and is the basis for downstream temperature control. This prevents excessively high or low temperatures from being unable to be quickly corrected within the secondary temperature adjustment unit 20, potentially causing harm to the patient or the downstream fluid circuit. It is easy to understand that the preheating safe temperature limit includes the preheating temperature range.

[0100] In this embodiment, the primary temperature control unit 10 includes a primary container 11, a primary temperature control actuator 12, and a primary flow pump 13. The primary container 11 is used to contain or place the liquid bag 17. The primary temperature control actuator 12 is used to regulate the liquid temperature inside the liquid bag 17 and keep the liquid temperature within a set preheating temperature range. The primary flow pump 13 is used to pump the preheated liquid into the liquid bladder 27 of the secondary temperature control unit 20 at a set flow rate. In this embodiment, the primary container 11 is a tray used to place the liquid bag 17. Of course, in other embodiments, the primary container 11 can also be a box or other structure used to store the liquid bag 17, which will not be described in detail here. The primary temperature control actuator 12 can be a common electric heating plate.

[0101] In this embodiment, the primary temperature control unit 10 further includes a first temperature sensor 14 disposed at the outlet of the primary container 11 or liquid bag 17 and a second temperature sensor 15 disposed on the primary temperature control actuator 12. Specifically, the first temperature sensor 14 is used to measure the liquid temperature inside the liquid bag 17, and the second temperature sensor 15 is used to measure the temperature of the primary temperature control actuator 12. The primary temperature control unit in this embodiment also includes a primary temperature control unit 16. The primary temperature control unit 16 receives the temperature data measured by the first temperature sensor 14 and the second temperature sensor 15, and controls the output power of the primary temperature control actuator 12. The control method of the primary temperature control unit 16 adopts PID feedback control, the principle of which is as follows:

[0102]

[0103] Where: U1(t) is the output power of the first-stage temperature control actuator 12; kp1 is the first proportional coefficient; T I T is the first integral time constant; D Let be the first differential time constant; t be time; err1(t) be the PID feedback adjustment deviation of the first-stage temperature control unit 10, and:

[0104] err1(t)=r1(t)―y1(t)

[0105] Where: r1(t) is the liquid temperature in the liquid bag 17 measured by the first temperature sensor 14; y1(t) is the temperature of the first-stage temperature control actuator 12 measured by the second temperature sensor 15.

[0106] In this embodiment, the secondary temperature control unit 20 includes a secondary container 21, a secondary temperature control actuator 22, and a secondary flow pump 23. The secondary container 21 is used to contain a liquid bladder 27, which is used to hold the pumped liquid. The secondary temperature control actuator 22 is used to regulate the temperature of the liquid inside the liquid bladder 27 and keep the liquid temperature within a set target temperature range. The secondary flow pump 23 is used to pump the temperature-controlled liquid out of the liquid bladder 27 at a set flow rate. In this embodiment, the secondary container 21 can be a box-shaped, sleeve-shaped, or other semi-open temperature control device for containing the liquid bladder 27, and the volume of the liquid bladder 27 is smaller than the liquid bag 17 used in the primary temperature control unit 10. The liquid bladder 27 can also be a heated liquid bag with a smaller volume than the liquid bag 17. If the secondary temperature control unit 20 is used for secondary heating, the secondary temperature control actuator 22 can be a common electric heating plate; if the secondary temperature control unit 20 is used for cooling, the secondary temperature control actuator 22 can be a cooling device such as a semiconductor cooler.

[0107] Specifically, the secondary temperature control unit 20 also includes a third temperature sensor 24 disposed at the liquid outlet of the liquid bladder 27 and a fourth temperature sensor 25 disposed on the secondary temperature control actuator 22; the third temperature sensor 24 is used to measure the liquid temperature inside the liquid bladder 27, and the fourth temperature sensor 25 is used to measure the temperature of the secondary temperature control actuator 22. In this embodiment, the secondary temperature control unit 20 also includes a secondary temperature control unit 26, which receives the temperature data measured by the third temperature sensor 24 and the fourth temperature sensor 25, and controls the output power of the secondary temperature control actuator 22. Specifically, the control method of the secondary temperature control unit 26 adopts PID feedback control, the principle of which is as follows:

[0108]

[0109] Where: Y2(t) is the output power of the secondary temperature control actuator 22; kp2 is the second proportional coefficient; T′ I The second integral time constant; T′ D Let be the second differential time constant; t be time; err2(t) be the PID feedback adjustment deviation of the secondary temperature control unit 20, and:

[0110] err2(t)=r2(t)―y2(t)

[0111] Where: r2(t) is the liquid temperature inside the liquid bladder 27 measured by the third temperature sensor 24; y2(t) is the temperature of the secondary temperature control actuator 22 measured by the fourth temperature sensor 24.

[0112] Specifically, the principle of PID feedback control is as follows: Figure 2 As shown, PID feedback control controls the temperature control actuators (first-stage temperature control actuator 12 and second-stage temperature control actuator 22) through the error signal. The control model of PID feedback control includes the sum of the proportional, integral, and derivative components. The continuous state formula of PID feedback control is:

[0113]

[0114] Where: U(t) is the output power of the temperature control actuator; kp is the first proportional coefficient; T I T is the first integral time constant; D Let be the first differential time constant; t be time; err(t) be the PID feedback control deviation, and:

[0115] err(t) = r(t) - y(t)

[0116] Where r(t) is the liquid temperature; y(t) is the temperature of the temperature control actuator.

[0117] Based on the continuous state formula of PID feedback control, it can be directly concluded that PID feedback control is essentially a process of controlling the deviation. In this embodiment, the PID control quantity is the actual power of the temperature control actuator, but the actual power of the temperature control actuator includes other influencing factors, such as the power dissipation P of the air. loss The heating yield η belongs to the proportional control part of the PID controller. The change in temperature difference and the residual heat of the temperature regulating actuator jointly affect the integral and derivative control parts of the PID controller, which in turn affect trend judgment and overshoot control. For example, a decrease in temperature difference and an increase in the residual heat of the temperature regulating actuator tend to result in overheating. In order to avoid overshoot, the output power needs to be reduced in advance.

[0118] Temperature control is limited by the following factors: air power dissipation P loss The heating yield η is the sum of the efficiency of the temperature control actuator and the thermal conductivity. It represents the power P required to heat m masses of liquid from an initial temperature T1 to T2 within a unit time t seconds. w For: P w =mC P (T2―T1), where: C P Let P be the specific heat capacity of the liquid. Therefore, the required output power is: P n =P w +P lossThe actual power of the temperature control actuator is The actual power P of the temperature control actuator decreases as the difference between the actual liquid temperature and the target temperature narrows.

[0119] At high flow rates, the liquid flows rapidly within the pipe, and the heat from the heating wire must pass through three layers of barriers: insulating silicone, the temperature-regulating actuator (metal plate), and the wall material of the liquid path, before it can be transferred to the liquid. At this point, the integral and derivative controls have reached their extreme values, the entire system reaches a steady state, and a steady-state error exists. Experimental measurements show that under conditions of a blood flow rate of 500 mL / min and a liquid pump flow rate of 50 mL / min, the liquid temperature is only 34℃ (room temperature 27℃), with a steady-state error of 3-4℃. Therefore, in this embodiment, a primary temperature control unit 10 is used to control the liquid temperature within a preheating temperature range close to the target temperature range. The temperature difference between the target temperature and the preheating temperature is compensated by a secondary temperature control unit 20, thus mitigating the significant error between the actual and theoretical liquid temperatures caused by poor thermal conductivity.

[0120] Specifically, the preheating temperature range and target temperature range can be designed in different ways depending on the equipment's temperature control strategy.

[0121] The first method: The maximum temperature value of the preheating temperature range falls within the target temperature range, and the minimum temperature value of the target temperature range falls within the preheating temperature range. For example, if the preheating temperature range is 30-36℃ and the target temperature range is 33-39℃, the maximum preheating temperature value of 36℃ falls within the target temperature range of 33-39℃, and the minimum target temperature value of 33℃ falls within the preheating temperature range of 30-36℃. The absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 2-3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 2-3℃. In this embodiment, the absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 3℃. At this point, the primary temperature control unit 10 controls the liquid temperature in the liquid bag 17 within the range of 30-36℃, and then the secondary temperature control unit 20 controls the temperature of the liquid pumped into the liquid bladder 27 within the range of 33-39℃. That is, the secondary temperature control unit 20 is used to heat the liquid and keep the liquid temperature within the target temperature range.

[0122] The second method involves preheating the temperature range so that the maximum temperature is less than the minimum temperature of the target temperature range. For example, if the preheating temperature range is 32-35℃ and the target temperature range is 36-39℃, the maximum preheating temperature (35℃) is less than the minimum target temperature (36℃). The absolute value of the difference between the maximum preheating temperature and the minimum target temperature is less than 3℃; in this embodiment, the absolute value of the difference is 1℃. In this case, the primary temperature control unit 10 controls the liquid temperature in the liquid bag 17 within the range of 32-35℃, and then the secondary temperature control unit 20 controls the temperature of the liquid pumped into the liquid bladder 27 within the range of 36-39℃. That is, the secondary temperature control unit 20 is used to heat the liquid and keep its temperature within the target temperature range.

[0123] The third method: The minimum temperature value of the preheating temperature range falls within the target temperature range, and the maximum temperature value of the target temperature range falls within the preheating temperature range. For example, the preheating temperature range is 36-42℃, and the target temperature range is 33-39℃. The minimum preheating temperature value of 36℃ falls within the target temperature range of 33-39℃, while the maximum target temperature value of 39℃ falls within the preheating temperature range of 36-42℃. The absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 2-3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 2-3℃. In this embodiment, the absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 3℃. At this point, the primary temperature control unit 10 controls the liquid temperature in the liquid bag 17 within the range of 36-42℃, and then the secondary temperature control unit 20 controls the temperature of the liquid pumped into the liquid bladder 27 within the range of 33-39℃. That is, the secondary temperature control unit 20 is used to cool the liquid and keep the liquid temperature within the target temperature range.

[0124] The fourth method: The minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range. For example, the preheating temperature range is 39-41℃, and the target temperature range is 36-38℃. The minimum temperature value of the preheating temperature range, 39℃, is greater than the maximum temperature value of the target temperature range, 38℃. The absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature range is less than 3℃; in this embodiment, the absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature range is 1℃. At this time, the primary temperature control unit 10 is used to control the liquid temperature in the liquid bag 17 within the range of 39-41℃, and then the secondary temperature control unit 20 is used to control the temperature of the liquid pumped into the liquid bladder 27 within the range of 36-38℃. That is, the secondary temperature control unit 20 is used to cool the liquid and keep the liquid temperature within the target temperature range.

[0125] In another embodiment, unlike the aforementioned two-stage PID feedback temperature control, the primary temperature control unit 10 still uses PID feedback control, but the secondary temperature control unit 20 does not use PID control. Instead, it uses constant-temperature heating and adjusts the heating temperature by small increments. The secondary temperature control unit 26 receives the temperature data measured by the third temperature sensor 24 and sets the heating temperature of the secondary temperature control actuator 22 according to the set target temperature and flow rate of the liquid supplied from the secondary temperature control unit 20 to the downstream end, and maintains it stable until the set target temperature and / or flow rate of the liquid supply changes. Then, the secondary temperature control unit 26 resets the heating temperature of the secondary temperature control actuator 22 and maintains it stable. This temperature control method is simpler and can avoid overshoot that may be caused by PID control. This two-stage temperature control system requires that the maximum allowable preheating temperature range of the primary temperature control unit 10 is less than the maximum value of the set target temperature range, i.e., overheating should not occur. Thus, the secondary temperature control actuator 22 uses a heating device for secondary heating. For the set target liquid supply temperature, the adjustable temperature range of the secondary temperature control actuator 22 is also relatively small, avoiding overheating issues that occur in existing liquid heating devices. This is easily achieved because existing heating jackets or hot plate devices transfer heat from the heating wires to the liquid inside the bladder through multiple layers of media, thus limiting their heating capacity and creating an inherent upper limit to the heating temperature. The actual heating temperature is tested based on the measured heating effect of the system to obtain the correspondence between the heating temperature of the secondary temperature control actuator 22 and the liquid temperature, which is stored in the device and recalled during device operation.

[0126] II. Dialysis System

[0127] like Figure 3 As shown, this embodiment also proposes a dialysis system, including a dialyzer 30. The dialyzer 30 is internally divided into a blood chamber and a dialysate chamber by a hollow fiber dialysis membrane. The blood chamber of the dialyzer 30 is provided with a blood inlet and a blood outlet, and the dialysate chamber is provided with a dialysate inlet and a waste liquid outlet. The blood inlet is connected to an arterial line 34, and the blood outlet is connected to a venous line 37, thereby forming an extracorporeal blood circuit. A blood pump 34 is provided on the arterial line 34. A dialysate supply system 31 is connected to the dialysate inlet of the dialyzer 30, and / or a replacement fluid inlet is provided on the arterial line 34 and / or the venous line 37. The replacement fluid inlet is connected to a replacement fluid supply system 32, which is a replacement fluid supply structure for pre-dilution, post-dilution, or mixed dilution treatment modes in clinical practice. Specifically, the dialysate supply system 31 in this embodiment is equipped with a dialysate temperature control system, and the replacement fluid supply system 32 is equipped with a replacement fluid temperature control system. Both the dialysate temperature control system and the replacement fluid temperature control system adopt the two-stage temperature control system of the CRRT equipment described above in this embodiment.

[0128] Specifically, both the dialysate supply system 31 and the replacement fluid supply system 32 include a supply tubing assembly. The supply tubing assembly and the fluid bag 17 are disposable consumables, working in conjunction with the liquid temperature control system of the CRRT equipment to form either the dialysate supply system or the replacement fluid supply system. The primary flow pump, secondary flow pump, and neutralization flow pump can all be peristaltic pumps. The supply tubing assembly includes an inlet, a fluid bladder 27, and pump tubing, connected by pipelines. The inlet of the supply tubing assembly is connected to the fluid bag 17 located within the primary container. The fluid bladder 27 is located within the secondary container 21. Each pump tubing corresponds to a peristaltic pump; the rotor rollers of the peristaltic pumps squeeze and release the pump tubing to drive the fluid flow. In this embodiment, a waste fluid pump 35 and a waste fluid bag 36 are connected to the dialysate outlet of the dialyzer 30.

[0129] Specifically, the primary temperature control units 10 of the dialysate temperature control system and the replacement fluid temperature control system can be integrated or separate. When the primary temperature control units 10 of the dialysate temperature control system and the replacement fluid temperature control system are integrated, the fluid bags of the dialysate supply system 31 and the replacement fluid supply system 32 are both placed in the same primary container and preheated simultaneously to the same preheating temperature range. Then, they are pumped into their respective independent secondary temperature control units 20 to be adjusted to the target temperature range. In this embodiment, the primary temperature control units 10 of the dialysate temperature control system and the replacement fluid temperature control system are separate. In this way, the two primary temperature control units 10 can be used to preheat and adjust the fluid bags of the dialysate supply system 31 and the replacement fluid supply system 32 to the set preheating temperature range, respectively.

[0130] III. Two-stage temperature control method for CRRT equipment

[0131] 3.1 First Implementation Method

[0132] like Figure 4 As shown in this embodiment, a two-stage temperature control method for a CRRT device first sets the target temperature zone [T] of the liquid supply according to the user-defined target liquid supply temperature. 21 ,T 22 ] and preheating target temperature zone [T 11 ,T 12 Then, adjust the temperature. The temperature adjustment process includes the following steps:

[0133] Step S1: Place the liquid bag 17 into the primary container 11.

[0134] Step S2: The primary temperature control unit 10 detects the liquid temperature inside the liquid bag 17 and makes a judgment based on the equipment's operating status: If the equipment's temperature control system is in the liquid supply preparation state, or if the equipment's temperature control system is in the liquid supply state but the liquid temperature inside the liquid bag 17 exceeds the preheating safety temperature limit, then temperature control is performed according to steps S21 to S24 to adjust the liquid bag temperature to the preheating target temperature zone [T]. 11 ,T12 If the equipment temperature control system is in liquid supply mode and the liquid temperature in the liquid bag 17 is within the preheating safe temperature limit, then proceed to step S3, and simultaneously adjust the temperature of the liquid remaining in the liquid bag 17 according to steps S21 to S24, adjusting the liquid bag temperature to the preheating target temperature zone [T]. 11 ,T 12 ].

[0135] Step S21: Use the first-level temperature control actuator 12 to adjust the temperature of the liquid in the liquid bag 17. After setting the unit time interval, execute step S22.

[0136] Step S22: Determine whether the liquid temperature T1 inside the liquid bag 17 is within the set preheating target temperature zone: If yes, proceed to step S24; if no, then: if the liquid temperature T1 inside the liquid bag 17 is less than the minimum temperature value T of the preheating target temperature zone... 11 Execute step S21; if the liquid temperature T1 in the liquid bag 17 is greater than the maximum temperature value T of the preheating target temperature zone. 12 Proceed to step S23.

[0137] Step S23: Turn off the first-stage temperature control actuator 12, set the unit time interval, and then execute step S22.

[0138] Step S24: Determine whether the temperature difference between the primary temperature control actuator 12 and the liquid temperature in the liquid bag 17 is within the steady-state temperature error range: if yes, it indicates that the primary temperature control unit 10 has reached a steady state, and step S2 is executed; if no, step S21 is executed.

[0139] Step S3: Use the primary flow pump 13 to pump the liquid in the liquid bag 17 into the liquid bladder 21 at the set flow rate.

[0140] Step S4: The secondary temperature control unit 20 detects the liquid temperature inside the liquid bladder 27 and makes a judgment based on the equipment's operating status: If the equipment's temperature control system is in the liquid supply preparation state, or the temperature control system is in the liquid supply state but the liquid temperature inside the liquid bladder 27 exceeds the preheating safety temperature limit, then temperature control is performed according to steps S41 to S44 to adjust the liquid temperature inside the liquid bladder to the target liquid supply temperature zone [T]. 21 ,T 22 If the equipment temperature control system is in liquid supply mode and the liquid temperature in the liquid bladder 27 is within the safe liquid supply temperature limit, then proceed to step S5, and simultaneously adjust the temperature of the liquid remaining in the liquid bladder 27 according to steps S41 to S44, adjusting the liquid temperature in the liquid bladder to the target liquid supply temperature range [T]. 21 ,T 22 This ensures that the temperature of the liquid flowing out of the liquid sac 27 is as close as possible to the target temperature.

[0141] Step S41: Determine whether the liquid temperature T2 inside the liquid bladder 21 is within the set target temperature range for liquid supply: If yes, proceed to step S44; if no, then: if the liquid temperature inside the liquid bladder 27 is less than the minimum temperature value T of the target temperature range for liquid supply. 21 Furthermore, the secondary temperature control actuator is a heating device, or the liquid temperature T2 in the liquid bladder 27 is greater than the maximum temperature value T of the target temperature zone for liquid supply. 22 Furthermore, the secondary temperature control actuator is a cooling device, executing step S42; if the liquid temperature in the liquid bladder 21 is greater than the maximum temperature value T of the target temperature zone for liquid supply. 22 Furthermore, the secondary temperature control actuator is a heating device, or the liquid temperature inside the liquid bladder 27 is less than the minimum temperature value T of the target temperature zone for liquid supply. 21 Furthermore, the secondary temperature control actuator is a cooling device, and it executes step S43.

[0142] Step S42: Use the secondary temperature control actuator 22 to adjust the temperature of the liquid in the liquid bladder 27. After setting the unit time interval, execute step S41.

[0143] Step S43: Turn off the secondary temperature control actuator 22, set the unit time interval, and then execute step S41.

[0144] Step S44: Determine whether the temperature difference between the secondary temperature control actuator 22 and the liquid temperature in the liquid bladder 21 is within the steady-state temperature error range: if yes, it indicates that the secondary temperature control unit 20 has reached a steady state, and step S4 is executed; if no, step S41 is executed.

[0145] Step S5: Pump the liquid out of the liquid bladder 27 using the secondary flow pump 23 according to the set flow rate.

[0146] The two-stage temperature control method for CRRT equipment in this embodiment is controlled in conjunction with the equipment status. Before dialysis treatment, the machine is in the treatment preparation stage (such as self-test or liquid heating) and treatment has not yet started. At this time, the equipment does not issue an instruction to the temperature control system to supply liquid to the downstream flow path, so the liquid in the fluid bag can be slowly heated to the preheating temperature. When the equipment's fluid supply system is in the downstream fluid supply state, such as during the pre-filling and venting stage of the extracorporeal blood circuit, dialysate circuit, and dialyzer, or after treatment is stopped and the fluid bag is replaced before continuing treatment, the equipment issues an instruction to supply liquid to the downstream flow path. At this time, supplying liquid to the downstream has higher priority. As long as the liquid is within the preheating safe temperature limit, liquid is supplied to the downstream, but at the same time, the temperature of the liquid in the fluid bag and fluid sac is adjusted so that the liquid temperature gradually reaches the set target temperature.

[0147] Specifically, the primary temperature control unit 10 includes a primary container 11, a primary temperature control actuator 12, a primary flow pump 13, a first temperature sensor 14, a second temperature sensor 15, and a primary temperature control unit 16. The primary container 11 is used to contain or place a liquid bag 17; the primary temperature control actuator 12 is used to regulate the liquid temperature inside the liquid bag 17 and keep the liquid temperature within a set preheating temperature range; the primary flow pump 13 is used to pump the preheated liquid into the secondary temperature control unit 20 at a set flow rate; the first temperature sensor 14 is located at the outlet of the primary container 11 or the liquid bag 17 and is used to measure the liquid temperature inside the liquid bag 17; the second temperature sensor 15 is located on the primary temperature control actuator 12 and is used to measure the temperature of the primary temperature control actuator 12; the primary temperature control unit 16 receives the temperature data measured by the first temperature sensor 14 and the second temperature sensor 15 and controls the output power of the primary temperature control actuator 12. Specifically, the control method of the primary temperature control unit 16 adopts PID feedback control, the principle of which is:

[0148]

[0149] Where: U1(t) is the output power of the first-stage temperature control actuator 12; kp1 is the first proportional coefficient; T I T is the first integral time constant; D Let be the first differential time constant; t be time; err1(t) be the PID feedback adjustment deviation of the first-stage temperature control unit 10, and:

[0150] err1(t)=r1(t)―y1(t)

[0151] Where: r1(t) is the liquid temperature in the liquid bag 17 measured by the first temperature sensor 14; y1(t) is the temperature of the first-stage temperature control actuator 12 measured by the second temperature sensor 15.

[0152] In this embodiment, the secondary temperature control unit 20 includes a secondary container 21, a secondary temperature control actuator 22, and a secondary flow pump 23. The secondary container 21 is used to contain a liquid bladder 27, which is used to hold the pumped liquid. The secondary temperature control actuator 22 is used to regulate the temperature of the liquid inside the liquid bladder 27 and keep the liquid temperature within a set target temperature range. The secondary flow pump 23 is used to pump the temperature-controlled liquid out of the liquid bladder 27 at a set flow rate. In this embodiment, the secondary container 21 can be a box-shaped, sleeve-shaped, or other semi-open temperature control device for containing the liquid bladder 27, and the volume of the liquid bladder 27 is smaller than the liquid bag 17 used in the primary temperature control unit 10. The liquid bladder 27 can also be a heated liquid bag with a smaller volume than the liquid bag 17. If the secondary temperature control unit 20 is used for secondary heating, the secondary temperature control actuator 22 can be a common electric heating plate; if the secondary temperature control unit 20 is used for cooling, the secondary temperature control actuator 22 can be a cooling device such as a semiconductor cooler.

[0153] Specifically, the secondary temperature control unit 20 also includes a third temperature sensor 24 disposed at the liquid outlet of the liquid bladder 27 and a fourth temperature sensor 25 disposed on the secondary temperature control actuator 22; the third temperature sensor 24 is used to measure the liquid temperature inside the liquid bladder 27, and the fourth temperature sensor 25 is used to measure the temperature of the secondary temperature control actuator 22. In this embodiment, the secondary temperature control unit 20 also includes a secondary temperature control unit 26, which receives the temperature data measured by the third temperature sensor 24 and the fourth temperature sensor 25, and controls the output power of the secondary temperature control actuator 22. Specifically, the control method of the secondary temperature control unit 26 adopts PID feedback control, the principle of which is as follows:

[0154]

[0155] Where: U2(t) is the output power of the secondary temperature control actuator 22; kp2 is the second proportional coefficient; T′ I The second integral time constant; T′ D Let be the second differential time constant; t be time; err2(t) be the PID feedback adjustment deviation of the secondary temperature control unit 20, and:

[0156] err2(t)=r2(t)―y2(t)

[0157] Where: r2(t) is the liquid temperature inside the liquid bladder 27 measured by the third temperature sensor 24; y2(t) is the temperature of the secondary temperature control actuator 22 measured by the fourth temperature sensor 24.

[0158] Specifically, the principle of PID feedback control is as follows: Figure 2As shown, PID feedback control controls the temperature control actuators (first-stage temperature control actuator 12 and second-stage temperature control actuator 22) through the error signal. The control model of PID feedback control includes the sum of the proportional, integral, and derivative components. The continuous state formula of PID feedback control is:

[0159]

[0160] Where: U(t) is the output power of the temperature control actuator; kp is the first proportional coefficient; T I T is the first integral time constant; D Let be the first differential time constant; t be time; err(t) be the PID feedback control deviation, and:

[0161] err(t) = r(t) - y(t)

[0162] Where r(t) is the liquid temperature; y(t) is the temperature of the temperature control actuator.

[0163] Based on the continuous state formula of PID feedback control, it can be directly concluded that PID feedback control is essentially a process of controlling the deviation. In this embodiment, the PID control quantity is the actual power of the temperature control actuator, but the actual power of the temperature control actuator includes other influencing factors, such as the power dissipation P of the air. loss The heating yield η belongs to the proportional control part of the PID controller. The change in temperature difference and the residual heat of the temperature regulating actuator jointly affect the integral and derivative control parts of the PID controller, which in turn affect trend judgment and overshoot control. For example, a decrease in temperature difference and an increase in the residual heat of the temperature regulating actuator tend to result in overheating. In order to avoid overshoot, the output power needs to be reduced in advance.

[0164] Temperature control is limited by the following factors: air power dissipation P loss The heating yield η is the sum of the efficiency of the temperature control actuator and the thermal conductivity. It represents the power P required to heat m masses of liquid from an initial temperature T1 to T2 within a unit time t seconds. w For: P w =mC P (T2―T1), where: C P Let P be the specific heat capacity of the liquid. Therefore, the required output power is: P n =P w +P loss The actual power of the temperature control actuator is The actual power P of the temperature control actuator decreases as the difference between the actual liquid temperature and the target temperature narrows.

[0165] At high flow rates, the liquid flows rapidly within the pipe, and the heat from the heating wire must pass through three layers of barriers: insulating silicone, the temperature-regulating actuator (metal plate), and the wall material of the liquid path, before it can be transferred to the liquid. At this point, the integral and derivative control have reached their extreme values, the entire system reaches a steady state, and a steady-state error exists. Experimental measurements show that under conditions of a blood flow rate of 500 mL / min and a liquid pump flow rate of 50 mL / min, the liquid temperature is only 34℃ (room temperature 27℃), with a steady-state error of 3-4℃. Therefore, in this embodiment, a primary temperature-regulating unit 10 is used to control the liquid temperature within a preheating temperature range close to the target temperature range. The temperature difference between the target temperature and the preheating temperature is compensated by a secondary temperature-regulating unit 20, thus mitigating the significant error between the actual and theoretical liquid temperatures caused by thermal conductivity efficiency. Specifically, in this embodiment, when the primary temperature-regulating unit 10 reaches a steady state, the temperature difference between the primary temperature-regulating actuator 12 and the liquid temperature inside the liquid bag 17 is 3-4℃. When the secondary temperature control unit 20 reaches a steady state, the temperature difference between the secondary temperature control actuator 22 and the liquid temperature in the liquid bladder 27 is 3-4℃.

[0166] Specifically, the preheating temperature range and target temperature range can be determined based on the liquid heating control strategy defined by the product design and functional requirements of the CRRT equipment, and implemented through product manufacturing.

[0167] The first method: The maximum temperature value of the preheating temperature range falls within the target temperature range, and the minimum temperature value of the target temperature range falls within the preheating temperature range. For example, if the preheating temperature range is 30-36℃ and the target temperature range is 33-39℃, the maximum preheating temperature value of 36℃ falls within the target temperature range of 33-39℃, and the minimum target temperature value of 33℃ falls within the preheating temperature range of 30-36℃. The absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 2-3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 2-3℃. In this embodiment, the absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 3℃. For example, when the user sets the target liquid supply temperature to 37°C, the equipment uses the primary temperature control unit 10 to control the liquid temperature in the liquid bag 17 within the range of 34-35°C, and then uses the secondary temperature control unit 20 to control the temperature of the liquid pumped into the secondary container 21 within the range of 36-38°C. That is, the secondary temperature control unit 20 is used to heat the liquid and keep the liquid temperature within the target liquid supply temperature range.

[0168] The second method involves setting the maximum preheating temperature range to be less than the minimum target temperature range. For example, if the preheating temperature range is 32-35℃ and the target temperature range is 36-39℃, the maximum preheating temperature range (35℃) is less than the minimum target temperature range (36℃). The absolute value of the difference between the maximum preheating temperature range and the minimum target temperature range is less than 3℃; in this embodiment, the absolute value of the difference is 1℃. For instance, when the user sets the target liquid supply temperature to 36℃, the primary temperature control unit 10 controls the liquid temperature in the liquid bag 17 to be within the range of 33-35℃, and then the secondary temperature control unit 20 controls the temperature of the liquid pumped into the secondary container 21 to be within the range of 35.5-36.5℃. In other words, the secondary temperature control unit 20 is used to heat the liquid and keep its temperature within the target liquid supply temperature range.

[0169] The third method: The minimum temperature value of the preheating temperature range falls within the target temperature range, and the maximum temperature value of the target temperature range falls within the preheating temperature range. For example, the preheating temperature range is 36-42℃, and the target temperature range is 33-39℃. The minimum preheating temperature value of 36℃ falls within the target temperature range of 33-39℃, while the maximum target temperature value of 39℃ falls within the preheating temperature range of 36-42℃. The absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 2-3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 2-3℃. In this embodiment, the absolute value of the difference between the minimum temperature value of the target temperature range and the minimum preheating temperature value is 3℃, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum preheating temperature value is also 3℃. For example, when the user sets the target liquid supply temperature to 39°C, the primary temperature control unit 10 controls the liquid temperature in the liquid bag 17 to be within the range of 40-41°C, and then the secondary temperature control unit 20 controls the temperature of the liquid pumped into the secondary container 21 to be within the range of 38.5-39.5°C. That is, the secondary temperature control unit 20 is used to cool the liquid and keep the liquid temperature within the target liquid supply temperature range.

[0170] The fourth method: The minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range. For example, the preheating temperature range is 39-41℃, and the target temperature range is 36-38℃. The minimum temperature value of the preheating temperature range, 39℃, is greater than the maximum temperature value of the target temperature range, 38℃. The absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature is less than 3℃; in this embodiment, the absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature is 1℃. For example, when the user sets the target liquid supply temperature to 37℃, the first-level temperature control unit 10 controls the liquid temperature in the liquid bag 17 within the range of 39-40℃, and then the second-level temperature control unit 20 controls the temperature of the liquid pumped into the liquid bladder 27 within the range of 36.5-37.5℃. That is, the second-level temperature control unit 20 is used to cool the liquid and keep the liquid temperature within the target liquid supply temperature range.

[0171] 3.2 Second Implementation Method

[0172] like Figure 5 As shown, in the two-stage temperature control method of the CRRT equipment in this embodiment, the primary temperature control unit 10 adopts the PID feedback regulation as described above, and the secondary temperature control unit 20 adopts constant temperature heating. After the user sets the target temperature for the liquid supply, the equipment automatically sets the target temperature zone for the liquid supply based on the liquid supply flow rate [T]. 21 ,T 22 ] and preheating target temperature zone [T 11 ,T 12 Then, adjust the temperature. The temperature adjustment process includes the following steps:

[0173] Step S1: Place the liquid bag 17 into the primary container 11.

[0174] Step S2: The primary temperature control unit 10 detects the liquid temperature T1 inside the liquid bag 17 and makes a judgment based on the equipment's operating status: If the equipment's temperature control system is in the liquid supply preparation state, or the temperature control system is in the liquid supply state but the liquid temperature inside the liquid bag 17 exceeds the preheating safe temperature limit, then temperature control is performed according to steps S21 to S24 to adjust the liquid bag temperature to the preheating target temperature zone [T]. 11 ,T 12 If the equipment temperature control system is in liquid supply mode and the liquid temperature in the liquid bag 17 is within the preheating safe temperature limit, then proceed to step S3, and simultaneously adjust the temperature of the liquid remaining in the liquid bag 17 according to steps S21 to S24, adjusting the liquid bag temperature to the preheating target temperature zone [T]. 11 ,T 12 ];

[0175] Step S21: Use the first-level temperature control actuator 12 to adjust the temperature of the liquid in the liquid bag 17. After setting the unit time interval, execute step S22.

[0176] Step S22: Determine whether the liquid temperature T1 inside the liquid bag 17 is within the set preheating target temperature zone [T 11 ,T 12 If yes, proceed to step S24; otherwise, if the liquid temperature T1 inside the liquid bag 17 is less than the minimum temperature value T of the preheating target temperature zone... 11 Execute step S21; if the liquid temperature T1 in the liquid bag 17 is greater than the maximum temperature value T of the preheating target temperature zone. 12 Proceed to step S23.

[0177] Step S23: Turn off the first-stage temperature control actuator 12, set the unit time interval, and then execute step S22.

[0178] Step S24: Determine whether the difference between the temperature of the primary temperature control actuator 12 and the liquid temperature T1 in the liquid bag 17 is within the steady-state temperature error range: if yes, it indicates that the primary temperature control unit 10 has reached a steady state, and step S2 is executed; if no, step S21 is executed.

[0179] Step S3: Use the primary flow pump 13 to pump the liquid in the liquid bag 17 into the liquid bladder 21 at the set flow rate.

[0180] Step S4: The secondary temperature control actuator of the secondary temperature control unit maintains the liquid bladder at the set heating temperature, while simultaneously determining the equipment's operating status: If the equipment's temperature control system is in the liquid supply preparation state, then follow steps S41-S42 to detect and adjust the temperature, adjusting the liquid temperature inside the bladder to the target liquid supply temperature zone [T]. 21 ,T 22 However, step S5 is not performed; if the equipment temperature control system is in liquid supply mode, then step S5 is performed, and temperature detection and adjustment are performed according to steps S41 to S42 to adjust the liquid temperature in the liquid bladder to the target liquid supply temperature zone [T]. 21 ,T 22 ];

[0181] Step S41: The secondary temperature control unit detects the liquid temperature T2 at the outlet of the liquid bladder and makes a judgment based on the pump flow rate: If the liquid temperature T2 at the outlet of the liquid bladder is lower than the minimum value T of the target temperature zone for liquid supply... 21 If the pump flow rate increases or decreases, then step S42 is executed; if the liquid temperature value T2 at the liquid bladder outlet is within the target temperature zone for liquid supply, or the heating temperature set by the secondary temperature control actuator has reached the allowable limit, then the currently set heating temperature of the secondary temperature control actuator remains unchanged.

[0182] Step S42: Reset the heating temperature of the secondary temperature control actuator. After setting the unit time interval, execute step S41.

[0183] Step S5: Pump the liquid out of the liquid bladder according to the set flow rate.

[0184] In this heating method, the secondary temperature control unit 26 sets and maintains the heating temperature of the secondary temperature control actuator 22 based on the set target liquid supply temperature and flow rate. This remains stable until the set target liquid supply temperature and / or flow rate changes. At this point, the secondary temperature control unit 26 resets and maintains the heating temperature of the secondary temperature control actuator 22, but the temperature adjustment range of the secondary temperature control actuator 22 does not exceed 2°C. For example, if the user sets the target liquid supply temperature to 37°C, the system automatically sets the heating temperature adjustment range of the secondary temperature control actuator 22 to 39-40°C. When the flow rate is low, heating is done at 39°C; when the flow rate increases, heating can be set to 40°C.

[0185] Other specific implementations of the two-stage temperature control method for CRRT equipment in this embodiment are the same as those in the first embodiment, and will not be described again.

[0186] Note: In this article, "and / or" refers to two logical relationships: "and" and "or". For example, "A and / or B" can mean "A or B" or "A and B".

[0187] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A two-stage temperature control system for CRRT equipment, characterized in that: It includes a primary temperature control unit and a secondary temperature control unit; The primary temperature control unit includes a primary container, a primary temperature control actuator and a primary flow pump. The primary container is used to contain or place the liquid bag. The primary temperature control actuator is used to control the liquid temperature T1 in the liquid bag and make the liquid temperature T1 within the set preheating target temperature zone [T 11 ,T 12 ], the primary temperature control unit has a preheating temperature range [T 1a ,T 1b ], The primary flow pump is used to pump the preheated liquid into the secondary temperature control unit according to a set flow rate; The secondary temperature control unit includes a secondary container, a secondary temperature control actuator and a secondary flow pump. The secondary container is used to contain a liquid capsule, which is used to contain the pumped liquid. The secondary temperature control actuator is used to control the liquid temperature T2 in the liquid capsule and make the liquid temperature T2 within the set liquid supply target temperature zone [T 21 ,T 22 ], the secondary temperature control unit has a target temperature range [T 2a ,T 2b ], The secondary flow pump is used to pump the temperature-adjusted liquid out of the liquid capsule at a set flow rate; The maximum temperature value of the preheating temperature range is within the target temperature range, and the minimum temperature value of the target temperature range is within the preheating temperature range; or, the maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range; The secondary temperature regulating unit is used to heat the liquid and make the liquid temperature fall within the target temperature range; or, The minimum temperature value of the preheating temperature range is within the target temperature range, and the maximum temperature value of the target temperature range is within the preheating temperature range; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range; The secondary temperature regulating unit is used to cool the liquid and make the temperature of the liquid fall within a target temperature range.

2. The two-stage temperature control system for CRRT equipment according to claim 1, characterized in that: The maximum temperature value of the preheating temperature range is within the target temperature range, and the minimum temperature value of the target temperature range is within the preheating temperature range; or, the minimum temperature value of the preheating temperature range is within the target temperature range, and the maximum temperature value of the target temperature range is within the preheating temperature range; The absolute value of the difference between the minimum temperature value of the target temperature range and the minimum temperature value of the preheating temperature is 2-3°C, and the absolute value of the difference between the maximum temperature value of the target temperature range and the maximum temperature value of the preheating temperature is 2-3°C.

3. The two-stage temperature control system for CRRT equipment according to claim 1, characterized in that: The maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range, and the absolute value of the difference between the maximum temperature value of the preheating temperature range and the minimum temperature value of the target temperature is 2-3°C; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range; The absolute value of the difference between the minimum temperature value of the preheating temperature range and the maximum temperature value of the target temperature is 2-3°C.

4. The two-stage temperature control system for CRRT equipment according to claim 1, characterized in that: The first-level temperature control unit also includes a first temperature sensor arranged at the liquid outlet of the first-level container or liquid bag and a second temperature sensor arranged on the first-level temperature control actuator; the first temperature sensor is used to measure the liquid temperature in the liquid bag, and the second temperature sensor is used to measure the temperature of the first-level temperature control actuator.

5. The two-stage temperature control system for CRRT equipment according to claim 4, characterized in that: The primary temperature control unit further includes a primary temperature control unit, which receives the temperature data measured by the first temperature sensor and the second temperature sensor and controls the output power of the primary temperature control actuator. The principle is: Where: U1(t) is the output power of the first-stage temperature control actuator; kp1 is the first proportional coefficient; T I is the first integral time constant; T D is the first differential time constant; t is time; err1(t) is the PID feedback adjustment deviation of the primary temperature control unit, and: err1(t)=r1(t)―y1(t) Wherein: r1(t) is the temperature of the liquid in the liquid bag measured by the first temperature sensor; y1(t) is the temperature of the primary temperature control actuator measured by the second temperature sensor.

6. The two-stage temperature control system for CRRT equipment according to claim 1, characterized in that: The secondary temperature control unit also includes a third temperature sensor arranged at the liquid outlet of the liquid sac and a fourth temperature sensor arranged on the secondary temperature control actuator; the third temperature sensor is used to measure the temperature of the liquid in the liquid sac, and the fourth temperature sensor is used to measure the temperature of the secondary temperature control actuator.

7. The two-stage temperature control system for CRRT equipment according to claim 6, characterized in that: The secondary temperature control unit further includes a secondary temperature control unit, which receives the temperature data measured by the third temperature sensor and the fourth temperature sensor and controls the output power of the secondary temperature control actuator. The principle is: Where: U2(t) is the output power of the secondary temperature control actuator; kp2 is the second proportional coefficient; T′ I is the second integral time constant; T′ D is the second differential time constant; t is time; err2(t) is the PID feedback adjustment deviation of the secondary temperature control unit, and: err2(t)=r2(t)―y2(t) Wherein: r2(t) is the temperature of the liquid in the liquid capsule measured by the third temperature sensor; y2(t) is the temperature of the secondary temperature control actuator measured by the fourth temperature sensor.

8. The two-stage temperature control system for CRRT equipment according to claim 6, characterized in that: The secondary temperature control unit also includes a secondary temperature control control unit, which receives the temperature data measured by the third temperature sensor, and sets the heating temperature of the secondary temperature control actuator and keeps it stable according to the set target temperature and flow rate of liquid supply from the secondary temperature control unit to the rear end until the set target temperature and / or flow rate of liquid supply changes, and the secondary temperature control unit resets the heating temperature of the secondary temperature control actuator and keeps it stable.

9. A dialysis system, comprising a dialyzer, wherein the dialyzer is provided with a blood inlet, a blood outlet, a dialysate inlet and a waste liquid outlet, wherein the blood inlet is connected to an arterial line, the blood outlet is connected to a venous line, the dialysate inlet is connected to a dialysate supply system, and / or the arterial line and / or the venous line is provided with a replacement fluid inlet, and the replacement fluid inlet is connected to the replacement fluid supply system, characterized in that: The dialysate supply system is provided with a dialysate temperature control system, and / or the replacement fluid supply system is provided with a replacement fluid temperature control system, and both the dialysate temperature control system and the replacement fluid temperature control system adopt the secondary temperature control system of the CRRT equipment as described in any one of claims 1-8.

10. A two-stage temperature control method for CRRT equipment, characterized in that: The device sets the target temperature zone [T 21 ,T 22 ] and the preheating target temperature zone [T 11 ,T 12 ]; The temperature adjustment process includes the following steps: Step S1: placing the liquid bag in a primary container; Step S2: The primary temperature control unit detects the temperature of the liquid in the liquid bag and makes a judgment based on the working status of the equipment: if the temperature control system of the equipment is in the liquid supply preparation state, or the temperature control system of the equipment is in the liquid supply state but the temperature of the liquid in the liquid bag exceeds the preheating safety temperature, the temperature of the liquid bag is adjusted to the preheating target temperature zone [T 11 ,T 12 ]; If the temperature control system of the equipment is in the liquid supply state and the liquid temperature in the liquid bag is within the preheating safety temperature limit, step S3 is performed to adjust the temperature of the liquid bag to the preheating target temperature zone [T 11 ,T 12 ]; Step S3: pumping the liquid in the fluid bag into the liquid bag in the secondary container according to the set flow rate; Step S4: The secondary temperature control unit detects the temperature of the liquid in the liquid capsule and makes a judgment based on the working status of the device: if the temperature control system of the device is in the liquid supply preparation state, or the temperature control system is in the liquid supply state but the temperature of the liquid in the liquid capsule exceeds the liquid supply safety temperature limit, then the temperature of the liquid in the liquid capsule is adjusted to the liquid supply target temperature zone [T 21 ,T 22 ]; If the temperature control system of the equipment is in the liquid supply state, and the temperature of the liquid in the liquid capsule is within the liquid supply safety temperature limit, then step S5 is performed to adjust the temperature of the liquid in the liquid capsule to the target temperature zone of the liquid supply [T 21 ,T 22 ]; Step S5: Pumping the liquid out of the liquid bag according to the set flow rate.

11. The two-stage temperature control method for CRRT equipment according to claim 10, characterized in that: Adjust the temperature of the liquid bag to the preheating target temperature range [T 11 ,T 12 The process of ] is carried out according to steps S21 to S24: Step S21: Use the primary temperature control actuator to control the temperature of the liquid in the liquid bag, and after setting the unit time interval, execute step S22; Step S22: Determine whether the temperature T1 of the liquid in the fluid bag is within the set preheating target temperature range [T 11 ,T 12 ]: If yes, execute step S24; if no, then: if the liquid temperature T1 in the liquid bag is less than the minimum temperature value T of the preheating target temperature zone 11 , execute step S21; if the liquid temperature T1 in the liquid bag is greater than the maximum temperature value T of the preheating target temperature zone 12 , execute step S23; Step S23: turn off the first-level temperature control actuator, set the unit time interval, and then execute step S22; Step S24: Determine whether the difference between the temperature of the primary temperature control actuator and the temperature of the liquid in the liquid bag is within the steady-state temperature error range: if so, it indicates that the primary temperature control unit has reached a steady state, and execute step S2; if not, execute step S21.

12. The two-stage temperature control method for CRRT equipment according to claim 10, characterized in that: Adjust the liquid temperature in the sac to the target temperature zone [T 21 ,T 22 The process of ] is performed according to steps S42 to S44: Step S41: Determine whether the temperature of the liquid in the liquid capsule is within the set liquid supply target temperature range [T 21 ,T 22 ]: If yes, then execute step S44; if no, then: if the liquid temperature T2 in the liquid capsule is less than the minimum temperature value T of the target temperature zone of the liquid supply 21 The secondary temperature control actuator is a heating device, or the liquid temperature T2 in the liquid capsule is greater than the maximum temperature value T of the target temperature zone of the liquid supply. 22 If the secondary temperature control actuator is a cooling device, execute step S42; if the liquid temperature in the liquid capsule is greater than the maximum temperature value T of the target temperature zone of the liquid supply 22 , and the secondary temperature control actuator is a heating device, or the liquid temperature in the liquid capsule is lower than the minimum temperature value T of the target temperature zone of the liquid supply 21 If the secondary temperature control actuator is a cooling device, execute step S43; Step S42: Use the secondary temperature control actuator to control the temperature of the liquid in the liquid capsule, and after setting the unit time interval, execute step S41; Step S43: turn off the secondary temperature control actuator, set the unit time interval, and then execute step S41; Step S44: Determine whether the difference between the temperature of the secondary temperature control actuator and the temperature of the liquid in the liquid capsule is within the steady-state temperature error range: if so, it indicates that the secondary temperature control unit has reached a steady state, and execute step S4; if not, execute step S41.

13. The two-stage temperature control method for CRRT equipment according to claim 10, characterized in that: The maximum temperature value of the preheating temperature range is within the target temperature range, and the minimum temperature value of the target temperature range is within the preheating temperature range; or, the minimum temperature value of the preheating temperature range is within the target temperature range, and the maximum temperature value of the target temperature range is within the preheating temperature range; The secondary temperature regulating unit is used for heating the liquid or cooling the liquid and making the temperature of the liquid fall within a target temperature range.

14. The two-stage temperature control method for CRRT equipment according to claim 10, characterized in that: The maximum temperature value of the preheating temperature range is less than the minimum temperature value of the target temperature range; or, the minimum temperature value of the preheating temperature range is greater than the maximum temperature value of the target temperature range; The secondary temperature regulating unit is used for heating the liquid or cooling the liquid and making the temperature of the liquid fall within a target temperature range.

15. The two-stage temperature control method for CRRT equipment according to claim 10, characterized in that: The primary temperature control unit further comprises a first temperature sensor disposed at the liquid outlet of the primary container or the liquid bag and a second temperature sensor disposed on the primary temperature control actuator; the first temperature sensor is used to measure the temperature of the liquid in the liquid bag, and the second temperature sensor is used to measure the temperature of the primary temperature control actuator; The secondary temperature control unit also includes a third temperature sensor arranged at the liquid outlet of the liquid sac and a fourth temperature sensor arranged on the secondary temperature control actuator; the third temperature sensor is used to measure the temperature of the liquid in the liquid sac, and the fourth temperature sensor is used to measure the temperature of the secondary temperature control actuator.

16. A two-stage temperature control method for CRRT equipment, characterized in that: The device sets the target temperature zone [T 21 ,T 22 ] and preheating target temperature zone [T 11 ,T 12 ]; wherein the maximum temperature value T of the preheating target temperature zone 12 Less than or equal to the maximum value T of the set liquid supply target temperature zone 22 ; The temperature adjustment process includes the following steps: Step S1: placing the liquid bag in a primary container; Step S2: The primary temperature control unit detects the temperature T1 of the liquid in the liquid bag, and makes a judgment in combination with the working state of the equipment: if the temperature control system of the equipment is in the liquid supply preparation state, or the temperature control system is in the liquid supply state but the temperature of the liquid in the liquid bag exceeds the preheating safety temperature limit, then the temperature is adjusted according to steps S21 to S24; if the temperature control system of the equipment is in the liquid supply state, and the temperature T1 of the liquid in the liquid bag is within the preheating safety temperature limit, then step S3 is performed, and the temperature of the liquid retained in the liquid bag is adjusted according to steps S21 to S24 at the same time; Step S21: Use the primary temperature control actuator to control the temperature of the liquid in the liquid bag, and after setting the unit time interval, execute step S22; Step S22: Determine whether the temperature T1 of the liquid in the fluid bag is within the set preheating target temperature range [T 11 ,T 12 ]: If yes, execute step S24; if no, then: if the liquid temperature T1 in the liquid bag is less than the minimum temperature value T of the preheating target temperature zone 11 , execute step S21; if the liquid temperature T1 in the liquid bag is greater than the maximum temperature value T of the preheating target temperature zone 12 , execute step S23; Step S23: turn off the first-level temperature control actuator, set the unit time interval, and then execute step S22; Step S24: determine whether the difference between the temperature of the primary temperature control actuator and the temperature T1 of the liquid in the liquid bag is within the steady-state temperature error range: if so, it indicates that the primary temperature control unit has reached a steady state, and step S2 is executed; if not, step S21 is executed; Step S3: pumping the liquid in the fluid bag into the liquid bag in the secondary container according to the set flow rate; Step S4: The secondary temperature control actuator of the secondary temperature control unit keeps the liquid capsule warm at the set heating temperature, and makes a judgment in combination with the working state of the device: if the temperature control system of the device is in the liquid supply preparation state, the temperature is detected and adjusted according to steps S41-S42; if the temperature control system of the device is in the liquid supply state, step S5 is performed, and the temperature is detected and adjusted according to steps S41-S42; Step S41: The secondary temperature control unit detects the liquid temperature T2 at the outlet of the liquid capsule, and makes a judgment in combination with the pump flow rate: if the liquid temperature value T2 at the outlet of the liquid capsule is not within the target temperature range of the liquid supply, and / or the pump flow rate is increased or the pump flow rate is decreased, then step S42 is executed; if the liquid temperature value T2 at the outlet of the liquid capsule is within the target temperature range of the liquid supply, or the heating temperature set by the secondary temperature control actuator has reached the limit value allowed to be set, then the currently set heating temperature of the secondary temperature control actuator is kept unchanged; Step S42: resetting the heating temperature of the secondary temperature control actuator, and after setting the unit time interval, executing step S41; Step S5: Pumping the liquid out of the liquid bag according to the set flow rate.

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