1. A continuous production method of a water-soluble polymer,
comprising:
circulating a circulation liquid containing a monomer having a polymerizable unsaturated bond through a reaction apparatus having a tank and a circulation line comprising a piping circulating outside the tank, and thereby producing a water-soluble polymer continuously; and
discharging part of the circulation liquid from a discharge line, wherein the circulation line is provided with a cooling device at least at one position; wherein a circulation ratio being calculated by dividing an amount of liquid returning to the tank by an amount of liquid discharged from the discharge line to the outside of the production apparatus is 3 or more and wherein a retention time of the circulation liquid in the tank and the circulation line (=a total amount of a reaction liquid an amount of the reaction liquid discharged per unit time) is 240 minutes or less, and wherein in the reaction apparatus, the tank, the cooling device, and the raw material supply port are disposed in this order in the flow passage direction of the circulation liquid, and the discharge line is positioned between the tank and the cooling device or the tank, the raw material supply port and the cooling device are disposed in this order in the flow passage direction of the circulation liquid, and the discharge line is positioned between the tank and the raw material supply port.
2. The continuous production method of the water-soluble polymer according to claim 1,
wherein a monomer conversion efficiency at an inlet of the tank is 90% or more.
3. The continuous production method of the water-soluble polymer according to claim 1,
wherein the retention time of the circulation liquid in the tank and the circulation line is 120 minutes or less and a difference in temperature between an inlet of the circulation line and an outlet of the circulation line is within 25\xb0 C.
4. The continuous production method of the water-soluble polymer according to claim 1,
wherein the discharge line is positioned between the tank and the raw material supply port in a flow passage direction of the circulation liquid.
5. The continuous production method of the water-soluble polymer according to claim 1,
wherein a monomer concentration at an outlet of the tank is 0.3 molkg or less.
6. The continuous production method of the water-soluble polymer according to claim 1,
wherein a metal simple substance containing a metal with a plurality of oxidation numbers as a constitutional component, a salt thereof andor a complex thereof areis added from at least one position of the circulation line.
7. The continuous production method of the water-soluble polymer according to claim 1,
wherein an oxidizing agent is added between the discharge line and a next step.
8. The continuous production method of the water-soluble polymer according to claim 1,
wherein a raw material comprises an unsaturated carboxylic acid monomer.
9. The continuous production method of the water-soluble polymer according to claim 2,
wherein the retention time of the circulation liquid in the tank and the circulation line is 120 minutes or less and a difference in temperature between an inlet of the circulation line and an outlet of the circulation line is within 25\xb0 C.
10. The continuous production method of the water-soluble polymer according to claim 5,
wherein the retention time of the circulation liquid in the tank and the circulation line is 120 minutes or less and a difference in temperature between an inlet of the circulation line and an outlet of the circulation line is within 25\xb0 C.
11. The continuous production method of the water-soluble polymer according to claim 1, wherein the cooling device satisfies a relationship between a volume of the circulation liquid V m3 and a heat transmission area of the cooling device S m2 of SV\u22675.
12. The continuous production method of the water-soluble polymer according to claim 1, wherein the discharge line is provided with the cooling device at least at one position.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A hitch angle warning system, comprising:
a hitch angle sensor sensing a current hitch angle between a vehicle and a trailer; and
a controller determining a future position of the trailer at a set time based on the current hitch angle and a speed of the vehicle and generating a warning signal when the future position exceeds a hitch angle threshold.
2. The hitch angle warning system of claim 1, further comprising:
a display for showing a visible warning when the warning signal is generated.
3. The hitch angle warning system of claim 1, further comprising:
a speaker for generating an audible warning when the warning signal is generated.
4. The hitch angle warning system of claim 1, wherein the future position is determined based on the speed of the vehicle.
5. The hitch angle warning system of claim 1, wherein the future position is determined based on the speed and a steering angle of the vehicle.
6. The hitch angle warning system of claim 1, wherein the future position is determined based on a length of the trailer, such that shorter length trailers will cause the warning signal to be generated before longer length trailers.
7. The hitch angle warning system of claim 1, wherein the future position includes a future hitch angle corresponding with a longitudinal centerline of the trailer in the future position.
8. The hitch angle warning system of claim 1, wherein the controller determines a maximum hitch angle controllable by the vehicle based on a length of the trailer, and wherein the hitch angle threshold is equal to the maximum hitch angle.
9. The hitch angle warning system of claim 1, wherein the controller generates a steering command for the vehicle to guide the trailer on a desired curvature based on a kinematic relationship between the vehicle and the trailer, wherein the desired curvature is defined with a steering input device.
10. A hitch angle warning system, comprising:
a hitch angle sensor sensing a hitch angle between a vehicle and a trailer; and
a controller estimating an amount of time for the hitch angle to reach a threshold angle based on a rate of change of the hitch angle and generating a warning signal when the amount of time is less than a threshold time.
11. The hitch angle warning system of claim 10, wherein the rate of change of the hitch angle is determined based on repetitively sensing the hitch angle over time.
12. The hitch angle warning system of claim 10, wherein the threshold time is configured to be greater than a response time of a driver of the vehicle.
13. The hitch angle warning system of claim 10, wherein the warning signal is deactivated when the amount of time is greater than a second time that is greater than the threshold time.
14. The hitch angle warning system of claim 10, further comprising:
a display for showing a visible warning when the warning signal is generated.
15. The hitch angle warning system of claim 10, further comprising:
a speaker for generating an audible warning when the warning signal is generated.
16. The hitch angle warning system of claim 10, wherein the amount of time for the hitch angle to reach the threshold angle is determined based on at least one of a speed of the vehicle, a steering angle of the vehicle, and a length of the trailer.
17. The hitch angle warning system of claim 10, wherein the controller determines a maximum hitch angle controllable by the vehicle based on a length of the trailer, and wherein the threshold angle is substantially equal to the maximum hitch angle.
18. A method for providing a hitch angle warning, comprising:
reversing a vehicle with a trailer attached;
sensing a hitch angle between the vehicle and the trailer;
determining an amount of time for the hitch angle to reach a threshold angle; and
generating a warning signal when the amount of time is less than a threshold time.
19. The method of claim 18, wherein the amount of time for the hitch angle to reach the threshold angle is determined based on a rate of change of the hitch angle.
20. The method of claim 19, further comprising:
determining a maximum hitch angle controllable by the vehicle based on a length of the trailer, and wherein the threshold angle is substantially equal to the maximum hitch angle.