std::default_random_engine generates the same values even with changing seed?

I'm trying to implement a class that will serve as sort of a wrapper for so I can use its objects and functions in (I think) a more intuitive way elsewhere in my code.

In my header I have something like this:

class RandomDevice{
private:
    unsigned long rand_seed;
    default_random_engine engine;
public:
    RandomDevice(unsigned long n);
    int randInt(int min, int max);};

And then in the .cpp file implements those two functions (constructor and randInt) like so:

RandomDevice::RandomDevice(unsigned long n){
    rand_seed = n;
    default_random_engine engine;
    engine.seed(n);
}

int RandomDevice::randInt(int min, int max){
    uniform_int_distribution<int> distribution(min, max);
    return distribution(engine);
}

Finally, in my main.cpp I test these functions like this:

int main(){
    unsigned long seed = 1;
    RandomDevice my_rand(seed);

    cout << "random integer: " << my_rand.randInt(0, 10) << endl;
}

The problem is, no matter what I set the seed to in main.cpp, I always get the same values for my random numbers (not just randInt, I have other distributions as well). I've also tried setting seed to time(NULL) but the same problem occurs.

I'm really scratching my head at this one. Thanks!