要在Angular 7中解决“Angular Auth拦截器无法刷新令牌”的问题，您可以尝试以下解决方法：

1. 在Auth拦截器中使用RxJS的retryWhen操作符来重新发送请求并刷新令牌。

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent, HttpResponse, HttpErrorResponse } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError, mergeMap, retryWhen, delay, take } from 'rxjs/operators';
import { AuthService } from './auth.service';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

  constructor(private authService: AuthService) { }

  intercept(request: HttpRequest, next: HttpHandler): Observable> {
    return next.handle(request).pipe(
      retryWhen((errors: Observable) => {
        return errors.pipe(
          mergeMap((error: HttpErrorResponse, count: number) => {
            if (count < 3 && error.status === 401) {
              // Refresh token and retry request
              return this.authService.refreshToken().pipe(
                delay(1000), // Delay between retries
                catchError((error: any) => {
                  this.authService.logout(); // Logout user if refresh token fails
                  return throwError(error);
                })
              );
            } else {
              return throwError(error);
            }
          }),
          take(3) // Retry max 3 times
        );
      }),
      catchError((error: HttpErrorResponse) => {
        // Handle other HTTP errors here
        return throwError(error);
      })
    );
  }
}

2. 在AuthService中实现refreshToken方法，并在其中发送刷新令牌的请求。

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable()
export class AuthService {

  constructor(private http: HttpClient) { }

  refreshToken(): Observable {
    const refreshToken = localStorage.getItem('refreshToken');

    // Send request to refresh token endpoint
    return this.http.post('http://example.com/refresh-token', { refreshToken }).pipe(
      tap((response: any) => {
        // Update access token and refresh token in local storage
        localStorage.setItem('accessToken', response.accessToken);
        localStorage.setItem('refreshToken', response.refreshToken);
      })
    );
  }

  logout() {
    // Clear access token and refresh token from local storage
    localStorage.removeItem('accessToken');
    localStorage.removeItem('refreshToken');
  }
}

请注意，上述代码仅作为示例，您可能需要根据自己的项目需求进行适当的修改和调整。

希望这可以帮助到您！