Postgres copy from CSV: how to format range variables?

Consider a Postgres table containing a range variable:

CREATE TABLE my_table (t_range tsrange, field1 text);

If I want to manually insert a row via psql, I can run:

INSERT INTO my_table (t_range, field1) VALUES ('[2014-06-02 07:00:00,infinity)'::tsrange, 'sometext');

Instead of inserting rows manually, I want to perform a bulk insert from a CSV file. I created a CSV file called my.csv using a similar format (using pipe as the delimiter to avoid having to escape the comma in the tsrange variable, and removing the explicit quote characters) with some content:

t_range|field1
'[2014-06-02 07:00:00,infinity)'::tsrange|'sometext1'
'[2014-06-02 07:00:00,infinity)'::tsrange|'sometext2'

Then from psql I ran

copy my_table FROM 'my.csv' DELIMITER '|' QUOTE '''' CSV HEADER;

but this failed with the error

ERROR:  malformed range literal: "[2014-06-02 07:00:00,infinity)::tsrange"
DETAIL:  Junk after right parenthesis or bracket.
CONTEXT:  COPY my_table, line 2, column t_range: "[2014-06-02 07:00:00,infinity)::tsrange"

How should I format a CSV file with range variables for use with copy?